WorldWideScience

Sample records for soot temperature measurements

  1. Optical measurements of soot and temperature profiles in premixed propane-oxygen flames

    Science.gov (United States)

    Lyons, V. J.; Pagni, P. J.

    1988-01-01

    Two laser diagnostic techniques were used to measure soot volume fractions, number densities and soot particle radii in premixed propane/oxygen flat flames. The two techniques used were two wavelength extinction, using 514.5 nm to 632.8 nm and 457.9 nm to 632.8 nm wavelength combinations, and extinction/scattering using 514.5 nm light. The flames were fuel-rich (equivalence ratios from 2.1 to 2.8) and had cold gas velocities varying from 3.4 to 5.5 cm/s. Measurements were made at various heights above the sintered-bronze, water-cooled flat flame burner with the equivalence ratio and cold gas velocity fixed. Also, measurements were made at a fixed height above the burner and fixed cold gas velocity while varying the equivalence ratio. Both laser techniques are based on the same underlying assumptions of particle size distribution and soot optical properties. Full Mie theory was used to determine the extinction coefficients K sub ext, and the scattering efficiencies, Q sub vv. Temperature measurements in the flames were made using infrared radiometry. Good agreement between the two techniques in terms of soot particle radii, number density and volume fraction was found for intensity ratios (I/I sub o) between 0.1 and 0.8. For intensity ratios higher or lower than this range, the differences in extinction coefficients at the wavelengths chosen for the two-wavelength method are too small to give accurate results for comparing particle radii and number densities. However, when comparing only soot volume fractions, the agreement between the two techniques continued to be good for intensity ratios up to 0.95.

  2. Soot measurements for diesel and biodiesel spray combustion under high temperature highly diluted ambient conditions

    KAUST Repository

    Zhang, Ji

    2014-11-01

    This paper presents the soot temperature and KL factor for biodiesel, namely fatty acid methyl ester (FAME) and diesel fuel combustion in a constant volume chamber using a two-color technique. The KL factor is a parameter for soot concentration, where K is an absorption coefficient and proportional to the number density of soot particles, L is the geometric thickness of the flame along the optical detection axis, and KL factor is proportional to soot volume fraction. The main objective is to explore a combustion regime called high-temperature and highly-diluted combustion (HTHDC) and compare it with the conventional and low-temperature combustion (LTC) modes. The three different combustion regimes are implemented under different ambient temperatures (800 K, 1000 K, and 1400 K) and ambient oxygen concentrations (10%, 15%, and 21%). Results are presented in terms of soot temperature and KL factor images, time-resolved pixel-averaged soot temperature, KL factor, and spatially integrated KL factor over the soot area. The time-averaged results for these three regimes are compared for both diesel and biodiesel fuels. Results show complex combined effects of the ambient temperature and oxygen concentration, and that two-color temperature for the HTHDC mode at the 10% oxygen level can actually be lower than the conventional mode. Increasing ambient oxygen and temperature increases soot temperature. Diesel fuel results in higher soot temperature than biodiesel for all three regimes. Results also show that diesel and biodiesel fuels have very different burning and sooting behavior under the three different combustion regimes. For diesel fuel, the HTHDC regime offers better results in terms of lower soot than the conventional and LTC regimes, and the 10% O2, 1400 K ambient condition shows the lowest soot concentration while maintaining a moderate two-color temperature. For biodiesel, the 15% O2, 800 K ambient condition shows some advantages in terms of reducing soot

  3. Wall temperature measurements at elevated pressures and high temperatures in sooting flames in a gas turbine model combustor

    Science.gov (United States)

    Nau, Patrick; Yin, Zhiyao; Geigle, Klaus Peter; Meier, Wolfgang

    2017-12-01

    Wall temperatures were measured with thermographic phosphors on the quartz walls of a model combustor in ethylene/air swirl flames at 3 bar. Three operating conditions were investigated with different stoichiometries and with or without additional injection of oxidation air downstream of the primary combustion zone. YAG:Eu and YAG:Dy were used to cover a total temperature range of 1000-1800 K. Measurements were challenging due to the high thermal background from soot and window degradation at high temperatures. The heat flux through the windows was estimated from the temperature gradient between the in- and outside of the windows. Differences in temperature and heat flux density profiles for the investigated cases can be explained very well with the previously measured differences in flame temperatures and flame shapes. The heat loss relative to thermal load is quite similar for all investigated flames (15-16%). The results complement previous measurements in these flames to investigate soot formation and oxidation. It is expected, that the data set is a valuable input for numerical simulations of these flames.

  4. Measurement of Soot Volume Fraction and Temperature for Oxygen-Enriched Ethylene Combustion Based on Flame Image Processing

    Directory of Open Access Journals (Sweden)

    Weijie Yan

    2017-05-01

    Full Text Available A method for simultaneously visualizing the two-dimensional distributions of temperature and soot volume fraction in an ethylene flame was presented. A single-color charge-coupled device (CCD camera was used to capture the flame image in the visible spectrum considering the broad-response spectrum of the R and G bands of the camera. The directional emissive power of the R and G bands were calibrated and used for measurement. Slightly increased temperatures and reduced soot concentration were predicted in the central flame without self-absorption effects considered, an iterative algorithm was used for eliminating the effect of self-absorption. Nine different cases were presented in the experiment to demonstrate the effects of fuel mass flow rate and oxygen concentration on temperature and soot concentration in three different atmospheres. For ethylene combustion in pure-air atmosphere, as the fuel mass flow rate increased, the maximum temperature slightly decreased, and the maximum soot volume fraction slightly increased. For oxygen fractions of 30%, 40%, and 50% combustion in O2/N2 oxygen-enhanced atmospheres, the maximum flame temperatures were 2276, 2451, and 2678 K, whereas combustion in O2/CO2 atmospheres were 1916, 2322, and 2535 K. The maximum soot volume fractions were 4.5, 7.0, and 9.5 ppm in oxygen-enriched O2/N2 atmosphere and 13.6, 15.3, and 14.8 ppm in oxygen-enriched O2/CO2 atmosphere. Compared with the O2/CO2 atmosphere, combustion in the oxygen-enriched O2/N2 atmosphere produced higher flame temperature and larger soot volume fraction. Preliminary results indicated that this technique is reliable and can be used for combustion diagnosis.

  5. Temperature, Oxygen, and Soot-Volume-Fraction Measurements in a Turbulent C2H4-Fueled Jet Flame

    Energy Technology Data Exchange (ETDEWEB)

    Kearney, Sean P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Guildenbecher, Daniel Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Winters, Caroline [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Farias, Paul Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grasser, Thomas W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hewson, John C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    We present a detailed set of measurements from a piloted, sooting, turbulent C 2 H 4 - fueled diffusion flame. Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (CARS) is used to monitor temperature and oxygen, while laser-induced incandescence (LII) is applied for imaging of the soot volume fraction in the challenging jet-flame environment at Reynolds number, Re = 20,000. Single-laser shot results are used to map the mean and rms statistics, as well as probability densities. LII data from the soot-growth region of the flame are used to benchmark the soot source term for one-dimensional turbulence (ODT) modeling of this turbulent flame. The ODT code is then used to predict temperature and oxygen fluctuations higher in the soot oxidation region higher in the flame.

  6. Effect of strain rate on sooting limits in counterflow diffusion flames of gaseous hydrocarbon fuels: Sooting temperature index and sooting sensitivity index

    KAUST Repository

    Wang, Yu

    2014-05-01

    The effect of the strain rate on the sooting limits in counterflow diffusion flames was investigated in various gaseous hydrocarbon fuels by varying the nitrogen dilution in the fuel and oxidizer streams. The sooting limit was defined as the critical fuel and oxygen mole fraction at which soot started to appear in the elastic light scattering signal. The sooting region for normal alkane fuels at a specified strain rate, in terms of the fuel and oxygen mole fraction, expanded as the number of carbon atoms increased. The alkene fuels (ethylene, propene) tested had a higher propensity for sooting as compared with alkane fuels with the same carbon numbers (ethane, propane). Branched iso-butane had a higher propensity for sooting than did n-butane. An increase in the strain rate reduced the tendency for sooting in all the fuels tested. The sensitivity of the sooting limit to the strain rate was more pronounced for less sooting fuels. When plotted in terms of calculated flame temperature, the critical oxygen mole fraction exhibited an Arrhenius form under sooting limit conditions, which can be utilized to significantly reduce the effort required to determine sooting limits at different strain rates. We found that the limiting temperatures of soot formation flames are viable sooting metrics for quantitatively rating the sooting tendency of various fuels, based on comparisons with threshold soot index and normalized smoke point data. We also introduce a sooting temperature index and a sooting sensitivity index, two quantitative measures to describe sooting propensity and its dependence on strain rate. © 2013 The Combustion Institute.

  7. Soot precursor measurements in benzene and hexane diffusion flames

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Furuhata, T.; Amagai, K.; Arai, M. [Department of Mechanical System Engineering, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515 (Japan)

    2008-08-15

    To clarify the mechanism of soot formation in diffusion flames of liquid fuels, measurements of soot and its precursors were carried out. Sooting diffusion flames formed by a small pool combustion equipment system were used for this purpose. Benzene and hexane were used as typical aromatic and paraffin fuels. A laser-induced fluorescence (LIF) method was used to obtain spatial distributions of polycyclic aromatic hydrocarbons (PAHs), which are considered as soot particles. Spatial distributions of soot in test flames were measured by a laser-induced incandescence (LII) method. Soot diameter was estimated from the temporal change of LII intensity. A region of transition from PAHs to soot was defined from the results of LIF and LII. Flame temperatures, PAH species, and soot diameters in this transition region were investigated for both benzene and hexane flames. The results show that though the flame structures of benzene and hexane were different, the temperature in the PAHs-soot transition region of the benzene flame was similar to that of the hexane flame. Furthermore, the relationship between the PAH concentrations measured by gas chromatography in both flames and the PAH distributions obtained from LIF are discussed. It was found that PAHs with smaller molecular mass, such as benzene and toluene, remained in both the PAHs-soot transition and sooting regions, and it is thought that molecules heavier than pyrene are the leading candidates for soot precursor formation. (author)

  8. Atmospheric soot aerosol measurements in Moscow

    Energy Technology Data Exchange (ETDEWEB)

    Kopeikin, V.M.; Pekour, M.S. [Institute of Atmospheric Physics, Moscow (Russian Federation)

    1996-12-31

    The results of regular soot concentration measurement in Moscow`s air for the period February 1989 - December 1995 are presented. The data obtained show that the level of soot contamination increased with the rate of approximately 0.42 mkg/m{sup 3} per year. 24-hour measurements of soot concentration and atmospheric boundary layer (ABL) parameters were carried out during 3 campaigns: May-June 1990, February 1991 and October-November 1993. Direct comparisons of local soot concentration with ABL characteristics reveals certain relationships, but also shows that local contamination strongly depends on many other parameters, such as source productivity, chemical reactions, air mass pre-history and so on.

  9. Temperature and velocity profiles in sooting free boundary layer flames

    Science.gov (United States)

    Ang, J. A.; Pagni, P. J.; Mataga, T. G.; Margle, J. M.; Lyons, V. J.

    1986-01-01

    Temperature and velocity profiles are presented for cyclohexane, n-heptane, and iso-octane free, laminar, boundary layer, sooting, diffusion flames. Temperatures are measured with 3 mil Pt/Pt-13 percent Rh thermocouples. Corrected gas temperatures are derived by performing an energy balance of convection to and radiation from the thermocouple bead incorporating the variation of air conductivity and platinum emissivity with temperature. Velocities are measured using laser doppler velocimetry techniques. Profiles are compared with previously reported analytic temperature and velocity fields. Comparison of theoretical and experimental temperature profiles suggests improvement in the analytical treatment is needed, which accounts more accurately for the local soot radiation. The velocity profiles are in good agreement, with the departure of the theory from observation partially due to the small fluctuations inherent in these free flows.

  10. Effects of ambient oxygen concentration on soot temperature and concentration for biodiesel and diesel spray combustion

    KAUST Repository

    Zhang, Ji

    2015-06-01

    Ambient oxygen concentration, a key variable directly related to exhaust gas recirculation (EGR) levels in diesel engines, plays a significant role in particulate matter (PM) and nitrogen oxides (NOx) emissions. The utilization of biodiesel in diesel engines has been investigated over the last decades for its renewable characteristics and lower emissions compared to diesel. In an earlier work, we demonstrated that the soot temperature and concentration of biodiesel were lower than diesel under regular diesel engine conditions without EGR. Soot concentration was quantified by a parameter called KL factor. As a continuous effort, this paper presents an experimental investigation of the ambient oxygen concentration on soot temperature and KL factor during biodiesel and diesel spray combustion. The experiment was implemented in a constant volume chamber system, where the ambient oxygen concentration varied from 21 to 10% and the ambient temperature was kept to 1,000 K. A high speed two-color pyrometry technique was used to measure transient soot temperature and the KL factor of the spray flame. The soot temperature of biodiesel is found to be lower than that of diesel under the same conditions, which follows the same trend from our previous results found when the ambient temperature changes to 21% oxygen conditions. A reduction in ambient oxygen concentration generally reduces the soot temperature for both fuels. However, this is a complicated effect on soot processes as the change of oxygen concentration greatly affects the balance between soot formation and oxidation. The KL factor is observed to be the highest at 12% O2 for diesel and 18% O2 for biodiesel, respectively. On the other hand, the 10% O2 condition shows the lowest KL factor for both fuels. These results can provide quantitative experimental evidences to optimize the ambient oxygen concentration for diesel engines using different fuels for better emissions characteristics. © 2014 American Society of

  11. Measurements of soot formation and hydroxyl concentration in near critical equivalence ratio premixed ethylene flame

    Science.gov (United States)

    Inbody, Michael Andrew

    1993-01-01

    The testing and development of existing global and detailed chemical kinetic models for soot formation requires measurements of soot and radical concentrations in flames. A clearer understanding of soot particle inception relies upon the evaluation and refinement of these models in comparison with such measurements. We present measurements of soot formation and hydroxyl (OH) concentration in sequences of flat premixed atmospheric-pressure C2H4/O2/N2 flames and 80-torr C2H4/O2 flames for a unique range of equivalence ratios bracketting the critical equivalence ratio (phi(sub c)) and extending to more heavily sooting conditions. Soot volume fraction and number density profiles are measured using a laser scattering-extinction apparatus capable of resolving a 0.1 percent absorption. Hydroxyl number density profiles are measured using laser-induced fluorescence (LIF) with broadband detection. Temperature profiles are obtained from Rayleigh scattering measurements. The relative volume fraction and number density profiles of the richer sooting flames exhibit the expected trends in soot formation. In near-phi(sub c) visibility sooting flames, particle scattering and extinction are not detected, but an LIF signal due to polycyclic aromatic hydrocarbons (PAH's) can be detected upon excitation with an argon-ion laser. A linear correlation between the argon-ion LIF and the soot volume fraction implies a common mechanistic source for the growth of PAH's and soot particles. The peak OH number density in both the atmospheric and 80-torr flames declines with increasing equivalence ratio, but the profile shape remains unchanged in the transition to sooting, implying that the primary reaction pathways for OH remain unchanged over this transition. Chemical kinetic modeling is demonstrated by comparing predictions using two current reaction mechanisms with the atmospheric flame data. The measured and predicted OH number density profiles show good agreement. The predicted benzene

  12. Effects of diluents on soot surface temperature and volume fraction in diluted ethylene diffusion flames at pressure

    KAUST Repository

    Kailasanathan, Ranjith Kumar Abhinavam

    2014-05-20

    Soot surface temperature and volume fraction are measured in ethylene/air coflowing laminar diffusion flames at high pressures, diluted with one of four diluents (argon, helium, nitrogen, and carbon dioxide) using a two-color technique. Both temperature and soot measurements presented are line-of-sight averages. The results aid in understanding the kinetic and thermodynamic behavior of the soot formation and oxidation chemistry with changes in diluents, ultimately leading to possible methods of reducing soot emission from practical combustion hardware. The diluted fuel and coflow exit velocities (top-hat profiles) were matched at all pressures to minimize shear effects. In addition to the velocity-matched flow rates, the mass fluxes were held constant for all pressures. Addition of a diluent has a pronounced effect on both the soot surface temperature and volume fraction, with the helium diluted flame yielding the maximum and carbon dioxide diluted flame yielding minimum soot surface temperature and volume fraction. At low pressures, peak soot volume fraction exists at the tip of the flame, and with an increase in pressure, the location shifts lower to the wings of the flame. Due to the very high diffusivity of helium, significantly higher temperature and volume fraction are measured and explained. Carbon dioxide has the most dramatic soot suppression effect. By comparing the soot yield with previously measured soot precursor concentrations in the same flame, it is clear that the lower soot yield is a result of enhanced oxidation rates rather than a reduction in precursor formation. Copyright © 2014 Taylor & Francis Group, LLC.

  13. In-situ measurements of the mixing state and optical properties of soot with implications for radiative forcing estimates.

    Science.gov (United States)

    Moffet, Ryan C; Prather, Kimberly A

    2009-07-21

    Our ability to predict how global temperatures will change in the future is currently limited by the large uncertainties associated with aerosols. Soot aerosols represent a major research focus as they influence climate by absorbing incoming solar radiation resulting in a highly uncertain warming effect. The uncertainty stems from the fact that the actual amount soot warms our atmosphere strongly depends on the manner and degree in which it is mixed with other species, a property referred to as mixing state. In global models and inferences from atmospheric heating measurements, soot radiative forcing estimates currently differ by a factor of 6, ranging between 0.2-1.2 W/m(2), making soot second only to CO(2) in terms of global warming potential. This article reports coupled in situ measurements of the size-resolved mixing state, optical properties, and aging timescales for soot particles. Fresh fractal soot particles dominate the measured absorption during peak traffic periods (6-9 AM local time). Immediately after sunrise, soot particles begin to age by developing a coating of secondary species including sulfate, ammonium, organics, nitrate, and water. Based on these direct measurements, the core-shell arrangement results in a maximum absorption enhancement of 1.6x over fresh soot. These atmospheric observations help explain the larger values for soot forcing measured by others and will be used to obtain closure in optical property measurements to reduce one of the largest remaining uncertainties in climate change.

  14. Measurement of Soot Deposition in Automotive Components Using Neutron Radiography

    International Nuclear Information System (INIS)

    Zekveld, David; Liu, Liaohui; Harrison, Andrew; Gill, Spencer; Harvel, Glenn; Chang, Jen-Shih

    2008-01-01

    About 40% of air pollution is generated by vehicles and transportation. The particulate matter (PM) emission significantly impacts human health. Fine particles below 2.5 μm (PM2.5) can enter the lungs and lead to respiratory problems. These particles not only influence human health, but also reduce the capability of many automobile exhaust heat exchanging devices. Neutron radiography is a non-destructive method of analyzing carbonaceous PM. While neutron radiography has been demonstrated for soot measurement in the past, the application has not considered the presence of unburned hydrocarbons, significant amounts of moisture nor examined complex geometrical configurations. The purpose of this work is to study a reliable non-destructive testing methodology using neutron radiography for measurement of soot distribution in automotive components. A soot standard (aluminium target) was designed and manufactured as a calibration tool. The standard is radiographed and used to measure the differences between various soot thickness and compositions. The radiograph images are analyzed to determine a calibration curve based upon the composition of the materials which can then be used for analysis of the automotive components. Experiments are performed using a diesel engine to produce soot deposits on exhaust piping. Soot distribution on exhaust piping is measured using neutron radiography. (authors)

  15. Effect of diluents on soot precursor formation and temperature in ethylene laminar diffusion flames

    KAUST Repository

    Abhinavam Kailasanathan, Ranjith Kumar

    2013-03-01

    Soot precursor species concentrations and flame temperature were measured in a diluted laminar co-flow jet diffusion flame at pressures up to eight atmospheres while varying diluent type. The objective of this study was to gain a better understanding of soot production and oxidation mechanisms, which could potentially lead to a reduction in soot emissions from practical combustion devices. Gaseous samples were extracted from the centerline of an ethylene-air laminar diffusion flame, which was diluted individually with four diluents (argon, helium, nitrogen, and carbon dioxide) to manipulate flame temperature and transport properties. The diluted fuel and co-flow exit velocities (top-hat profiles) were matched at all pressures to minimize shear-layer effects, and the mass fluxes were fixed over the pressure range to maintain constant Reynolds number. The flame temperature was measured using a fine gauge R-type thermocouple at pressures up to four atmospheres. Centerline concentration profiles of major non-fuel hydrocarbons collected via extractive sampling with a quartz microprobe and quantification using GC/MS+FID are reported within. The measured hydrocarbon species concentrations are vary dramatically with pressure and diluent, with the helium and carbon dioxide diluted flames yielding the largest and smallest concentrations of soot precursors, respectively. In the case of C2H2 and C6H6, two key soot precursors, helium diluted flames had concentrations more than three times higher compared with the carbon dioxide diluted flame. The peak flame temperature vary with diluents tested, as expected, with carbon dioxide diluted flame being the coolest, with a peak temperature of 1760K at 1atm, and the helium diluted flame being the hottest, with a peak temperature of 2140K. At four atmospheres, the helium diluted flame increased to 2240K, but the CO2 flame temperature increased more, decreasing the difference to approximately 250K. © 2012 The Combustion Institute.

  16. Studies of propane flame soot acting as heterogeneous ice nuclei in conjunction with single particle soot photometer measurements

    Directory of Open Access Journals (Sweden)

    I. Crawford

    2011-09-01

    Full Text Available The ice nucleation efficiency of propane flame soot particles with and without a sulphuric acid coating was investigated using the aerosol and cloud chamber facility AIDA (Aerosol Interaction and Dynamics in the Atmosphere. The test soot for cloud formation simulations was produced using a propane flame Combustion Aerosol Standard generator (CAST, Jing-CAST Technologies. The organic carbon content (OC of the test soot was altered in a reproducible fashion by changing the fuel/air mixture of the generator. The soot content of ice nuclei was subsequently investigated using a combination of a pumped counterflow virtual impactor (PCVI to separate and evaporate the ice crystals, and a DMT single particle soot photometer (SP2 to examine the mixing state of the BC containing ice residuals.

    Ice nucleation was found to be most efficient for uncoated soot of low organic carbon content (~5 % organic carbon content where deposition freezing occurred at an ice saturation ratio Sice ~ 1.22 at a temperature T = 226.6 K with 25 % of the test soot becoming active as ice nuclei. Propane flame soot of higher organic carbon content (~30 % and ~70 % organic carbon content showed significantly lower ice nucleation efficiency (an activated fraction of the order of a few percent in the experiments than the low organic carbon content soot, with water saturation being required for freezing to occur. Ice nucleation occurred over the range Sice = 1.22–1.70, and T = 223.2–226.6 K. Analysis of the SP2 data showed that the 5 % organic carbon content soot had an undetectable OC coating whereas the 30 % organic carbon content soot had a thicker or less volatile OC coating.

    The application of a sulphuric acid coating to the flame soot shifted the threshold of the onset of freezing towards that of the homogeneous freezing of sulphuric acid; for the minimum OC flame soot this inhibited nucleation since the

  17. Exploring Soot Particle Concentration and Emissivity by Transient Thermocouples Measurements in Laminar Partially Premixed Coflow Flames

    Directory of Open Access Journals (Sweden)

    Gianluigi De Falco

    2017-02-01

    Full Text Available Soot formation in combustion represents a complex phenomenon that strongly depends on several factors such as pressure, temperature, fuel chemical composition, and the extent of premixing. The effect of partial premixing on soot formation is of relevance also for real combustion devices and still needs to be fully understood. An improved version of the thermophoretic particle densitometry (TPD method has been used in this work with the aim to obtain both quantitative and qualitative information of soot particles generated in a set of laminar partially-premixed coflow flames characterized by different equivalence ratios. To this aim, the transient thermocouple temperature response has been analyzed to infer particle concentration and emissivity. A variety of thermal emissivity values have been measured for flame-formed carbonaceous particles, ranging from 0.4 to 0.5 for the early nucleated soot particles up to the value of 0.95, representing the typical value commonly attributed to mature soot particles, indicating that the correct determination of the thermal emissivity is necessary to accurately evaluate the particle volume fraction. This is particularly true at the early stage of the soot formation, when particle concentration measurement is indeed particularly challenging as in the central region of the diffusion flames. With increasing premixing, an initial increase of particles is detected both in the maximum radial soot volume fraction region and in the central region of the flame, while the further addition of primary air determines the particle volume fraction drop. Finally, a modeling analysis based on a sectional approach has been performed to corroborate the experimental findings.

  18. Laser-induced incandescence: Towards quantitative soot volume fraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tzannis, A.P.; Wienbeucker, F.; Beaud, P.; Frey, H.-M.; Gerber, T.; Mischler, B.; Radi, P.P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Laser-Induced Incandescence has recently emerged as a versatile tool for measuring soot volume fraction in a wide range of combustion systems. In this work we investigate the essential features of the method. LII is based on the acquisition of the incandescence of soot when heated through a high power laser pulse. Initial experiments have been performed on a model laboratory flame. The behaviour of the LII signal is studied experimentally. By applying numerical calculations we investigate the possibility to obtain two-dimensional soot volume fraction distributions. For this purpose a combination of LII with other techniques is required. This part is discussed in some extent and the future work is outlined. (author) 4 figs., 3 refs.

  19. Soot temperature and KL factor for biodiesel and diesel spray combustion in a constant volume combustion chamber

    KAUST Repository

    Zhang, Ji

    2013-07-01

    This paper presents measurements of the soot temperature and KL factor for biodiesel and diesel combustion in a constant volume chamber using a two-color technique. This technique uses a high-speed camera coupled with two narrowband filters (550. nm and 650. nm, 10. nm FWHM). After calibration, statistical analysis shows that the uncertainty of the two-color temperature is less than 5%, while it is about 50% for the KL factor. This technique is then applied to the spray combustion of biodiesel and diesel fuels under an ambient oxygen concentration of 21% and ambient temperatures of 800, 1000 and 1200. K. The heat release result shows higher energy utilization efficiency for biodiesel compared to diesel under all conditions; meanwhile, diesel shows a higher pressure increase due to its higher heating value. Biodiesel yields a lower temperature inside the flame area, a longer soot lift-off length, and a smaller soot area compared to diesel. Both the KL factor and the total soot with biodiesel are lower than with diesel throughout the entire combustion process, and this difference becomes larger as the ambient temperature decreases. Biodiesel shows approximately 50-100. K lower temperatures than diesel at the quasi-steady stage for 1000 and 1200. K ambient temperature, while diesel shows a lower temperature than biodiesel at 800. K ambient. This result may raise the question of how important the flame temperature is in explaining the higher NO. x emissions often observed during biodiesel combustion. Other factors may also play an important role in controlling NO. x emissions. Both biodiesel and diesel temperature measurements show a monotonic dependence on the ambient temperature. However, the ambient temperature appears to have a more significant effect on the soot formation and oxidation in diesel combustion, while biodiesel combustion soot characteristics shows relative insensitivity to the ambient temperature. © 2013 Elsevier Ltd.

  20. Laboratory measurements of soot particle density change due to water uptake.

    Science.gov (United States)

    Crosbie, E.

    2015-12-01

    Black carbon containing soot particles are an important aerosol subclass owing to their light-absorbing properties. Furthermore, soot particles present challenges with regard to characterization and modeling of their microphysical, chemical, and optical properties, because of their inherent non-spherical, fractal morphology. Aggregation/coagulation of soot adds to the complexity of the particle morphology, while co-emitted organic compounds affect the chemical composition both during emission and though aging, which causes partitioning of secondary organic aerosol. Measurements of soot particles from vehicular and jet engine exhaust plumes have shown that the effective density can vary over a broad range (0.3-1.8 gm-3) and is affected by the fuel burn characteristics (fuel type, fuel equivalence ratio, combustion temperature), the particle size, and the extent of the aggregation. The action of organic coatings and the uptake of particle water, through hygroscopic growth, can cause a dramatic change in the morphology of soot. Restructuring of the fractal morphology into a more compact form has the effect of increasing the effective particle density, thus reducing the particle size, with important implications for the optical and hygroscopic properties. We present measurements of size-resolved particle density from laboratory generated fresh soot particles, under a range of operating conditions. We first filter by particle mass using an aerosol particle mass (APM) centrifugal analyzer and then subject the sample to a pre-humidification cycle in order to initiate particle restructuring. Finally, the sample is dried and the mobility size distribution is measured using a scanning mobility particle sizer (SMPS). A range of particle masses is scanned to determine the density as a function of size and, for each mass set point, a range of relative humidity settings are scanned to determine the extent of restructuring. We discuss the findings in relation to atmospherically

  1. An investigation into the characterisation of the laser-induced incandescence method for the measurement of soot in practical systems

    OpenAIRE

    Grigorian, V.

    2002-01-01

    The thesis describes the characterisation and application of the laser induced incandescence technique for making soot measurements in practical devices. Laser induced incandescence is the phenomenon whereby particulates such a soot absorb laser radiation and are heated to a temperature much higher than the bath gas. The broadband incandescence signal from the hot particles can be detected and the signal is proportional to volume fraction. The technique was used ...

  2. Simultaneous measurements of acetylene and soot during the pyrolysis of ethylene and benzene in a shock tube

    KAUST Repository

    KC, Utsav

    2016-10-12

    Acetylene is one of the most important precursors of soot and contributes to soot growth by the hydrogen-abstraction acetylene-addition (HACA) mechanism. In this work, we undertake time-resolved simultaneous measurements of acetylene and soot behind reflected shock waves at temperatures of 1600-2200. K and pressures of 3-5. bar. Acetylene mole fraction time-histories are measured from the absorption of a quantum-cascade laser operating around 13.6. μm. The soot volume fraction, particle size and number densities are calculated from the extinction and scattering of a cw Nd:Yag laser at 532. nm. Acetylene and soot are generated from the pyrolysis of 1% benzene in argon, 2.35% ethylene in argon, and binary mixtures of ethylene with propane/methane in argon. We note that acetylene time-histories exhibit a two-stage growth during the pyrolysis of benzene, which can be correlated to the initial rapid increase of soot volume fraction and a later plateauing. In comparison to ethylene pyrolysis, the pyrolysis of benzene results in larger values of the soot volume fraction, particle diameter and number density. We compare the measured data against the values simulated using the method-of-moments routine in Chemkin-Pro and a detailed PAH mechanism based on KM2 [1] and AramcoMech 1.3 [2]. Large discrepancies are observed between the measured and predicted values of the soot parameters. The data obtained from our experiments may assist future validation and development of soot mechanisms.

  3. Measurements and Modeling of Soot Formation and Radiation in Microgravity Jet Diffusion Flames. Volume 4

    Science.gov (United States)

    Ku, Jerry C.; Tong, Li; Greenberg, Paul S.

    1996-01-01

    This is a computational and experimental study for soot formation and radiative heat transfer in jet diffusion flames under normal gravity (1-g) and microgravity (0-g) conditions. Instantaneous soot volume fraction maps are measured using a full-field imaging absorption technique developed by the authors. A compact, self-contained drop rig is used for microgravity experiments in the 2.2-second drop tower facility at NASA Lewis Research Center. On modeling, we have coupled flame structure and soot formation models with detailed radiation transfer calculations. Favre-averaged boundary layer equations with a k-e-g turbulence model are used to predict the flow field, and a conserved scalar approach with an assumed Beta-pdf are used to predict gaseous species mole fraction. Scalar transport equations are used to describe soot volume fraction and number density distributions, with formation and oxidation terms modeled by one-step rate equations and thermophoretic effects included. An energy equation is included to couple flame structure and radiation analyses through iterations, neglecting turbulence-radiation interactions. The YIX solution for a finite cylindrical enclosure is used for radiative heat transfer calculations. The spectral absorption coefficient for soot aggregates is calculated from the Rayleigh solution using complex refractive index data from a Drude- Lorentz model. The exponential-wide-band model is used to calculate the spectral absorption coefficient for H20 and C02. It is shown that when compared to results from true spectral integration, the Rosseland mean absorption coefficient can provide reasonably accurate predictions for the type of flames studied. The soot formation model proposed by Moss, Syed, and Stewart seems to produce better fits to experimental data and more physically sound than the simpler model by Khan et al. Predicted soot volume fraction and temperature results agree well with published data for a normal gravity co-flow laminar

  4. Measuring and predicting sooting tendencies of oxygenates, alkanes, alkenes, cycloalkanes, and aromatics on a unified scale

    Energy Technology Data Exchange (ETDEWEB)

    Das, Dhrubajyoti D.; St. John, Peter C.; McEnally, Charles S.; Kim, Seonah; Pfefferle, Lisa D.

    2018-04-01

    Databases of sooting indices, based on measuring some aspect of sooting behavior in a standardized combustion environment, are useful in providing information on the comparative sooting tendencies of different fuels or pure compounds. However, newer biofuels have varied chemical structures including both aromatic and oxygenated functional groups, which expands the chemical space of relevant compounds. In this work, we propose a unified sooting tendency database for pure compounds, including both regular and oxygenated hydrocarbons, which is based on combining two disparate databases of yield-based sooting tendency measurements in the literature. Unification of the different databases was made possible by leveraging the greater dynamic range of the color ratio pyrometry soot diagnostic. This unified database contains a substantial number of pure compounds (greater than or equal to 400 total) from multiple categories of hydrocarbons important in modern fuels and establishes the sooting tendencies of aromatic and oxygenated hydrocarbons on the same numeric scale for the first time. Using this unified sooting tendency database, we have developed a predictive model for sooting behavior applicable to a broad range of hydrocarbons and oxygenated hydrocarbons. The model decomposes each compound into single-carbon fragments and assigns a sooting tendency contribution to each fragment based on regression against the unified database. The model's predictive accuracy (as demonstrated by leave-one-out cross-validation) is comparable to a previously developed, more detailed predictive model. The fitted model provides insight into the effects of chemical structure on soot formation, and cases where its predictions fail reveal the presence of more complicated kinetic sooting mechanisms. This work will therefore enable the rational design of low-sooting fuel blends from a wide range of feedstocks and chemical functionalities.

  5. The investigation of soot and temperature distributions in a visualized direct injection diesel engine using laser diagnostics

    Science.gov (United States)

    Han, Yong-taek; Kim, Ki-bum; Lee, Ki-hyung

    2008-11-01

    Based upon the method of temperature calibration using the diffusion flame, the temperature and soot concentrations of the turbulent flame in a visualized diesel engine were qualitatively measured. Two different cylinder heads were used to investigate the effect of swirl ratio within the combustion chamber. From this experiment, we find that the highest flame temperature of the non-swirl head engine is approximately 2400 K and that of the swirl head engine is 2100 K. In addition, as the pressure of fuel injection increases, the in-cylinder temperature increases due to the improved combustion of a diesel engine. This experiment represented the soot quantity in the KL factor and revealed that the KL factor was high when the fuel collided with the cylinder wall. Moreover, the KL factor was also high in the area of the chamber where the temperature dropped rapidly.

  6. Effects of morphology and wavelength on the measurement accuracy of soot volume fraction by laser extinction

    Science.gov (United States)

    Wang, Ya-fei; Huang, Qun-xing; Wang, Fei; Chi, Yong; Yan, Jian-hua

    2018-01-01

    A novel method to evaluate the quantitative effects of soot morphology and incident wavelength on the measurement accuracy of soot volume fraction, by the laser extinction (LE) technique is proposed in this paper. The results indicate that the traditional LE technique would overestimate soot volume fraction if the effects of morphology and wavelength are not considered. Before the agglomeration of isolated soot primary particles, the overestimation of the LE technique is in the range of 2-20%, and rises with increasing primary particle diameter and with decreasing incident wavelength. When isolated primary particles are agglomerated into fractal soot aggregates, the overestimation would exceed 30%, and rise with increasing primary particle number per soot aggregate, fractal dimension and fractal prefactor and with decreasing incident wavelength to a maximum value of 55%. Finally, based on these results above, the existing formula of the LE technique gets modified, and the modification factor is 0.65-0.77.

  7. Sooting limit in counterflow diffusion flames of ethylene/propane fuels and implication to threshold soot index

    KAUST Repository

    Joo, Peter H.

    2013-01-01

    Sooting limits in counterflow diffusion flames of propane/ethylene fuels have been studied experimentally using a light scattering technique, including the effects of dilution, fuel mixing, and strain rate. The results are discussed in view of the threshold soot index (TSI). In soot-formation (SF) flames, where the flame is located on the oxidizer side of the stagnation plane, the sooting limit depends critically on fuel type and subsequently on flame temperature. The sooting limit has a non-linear dependence on the fuel-mixing ratio, which is similar to the non-linear mixing rule for TSI observed experimentally in rich premixed flames, where soot oxidation is absent for both SF and rich premixed flames. In soot-formation-oxidation (SFO) flames, where the flame is located on the fuel side, the sooting limit depends critically on flame temperature, while it is relatively independent on fuel type. This result suggests a linear mixing rule for sooting limits in SFO flames, which is similar to the TSI behavior for coflow diffusion flames. Soot oxidation takes place for both types of flames. The aerodynamic strain effect on the sooting limits has also been studied and an appreciable influence has been observed. Under sooting conditions, soot volume fraction was measured using a light extinction technique. The soot loadings in SF flames of the mixture fuels demonstrated a synergistic effect, i.e., soot production increased for certain mixture fuels as compared to the respective singlecomponent fuels. © 2012 The Combustion Institute.

  8. Spatially-resolved measurements of soot size and population in a swirl-stabilized combustor

    OpenAIRE

    Wood, CP; Smith, RA; Samuelsen, GS

    1985-01-01

    Isooctane, and mixtures of isooctane with various ring and aromatic compounds blended to yield the same smoke point were separately injected through a twin-fluid atomizer into a turbulent, swirl-stabilized model combustor. A nonintrusive optical probe based on larege angle (60°, 20°) intensity ratio scattering was used to yield a point measurement of soot particulate in the size range of 0.08 to 0.38 μm. The velocity and temperature fields were characterized by a two-color laser anemometer an...

  9. Chemical mechanism for high temperature combustion of engine relevant fuels with emphasis on soot precursors

    OpenAIRE

    Blanquart, G.; Pepiot-Desjardins, P.; Pitsch, H.

    2009-01-01

    This article presents a chemical mechanism for the high temperature combustion of a wide range of hydrocarbon fuels ranging from methane to iso-octane. The emphasis is placed on developing an accurate model for the formation of soot precursors for realistic fuel surrogates for premixed and diffusion flames. Species like acetylene (C_2H_2), propyne (C_3H_4), propene (C_3H_6), and butadiene (C_4H_6) play a major role in the formation of soot as their decomposition leads to the production of rad...

  10. Effects of Biomass Feedstock on the Yield and Reactivity of Soot from Fast Pyrolysis at High Temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Jensen, Peter A.; Glarborg, Peter

    microscopy techniques, X-ray diffraction and N2-adsorption. The reactivity of soot was investigated by thermogravimetric analysis. The results showed that the reactivity of soot, generated at 1400°C was higher than that at 1250°C for all biomass types. Wood and wheat straw soot demonstrated differences......This study investigated the effect of feedstock on the yield, nanostructure and reactivity of soot. Woody and herbaceous biomass were pyrolyzed at high heating rates and temperatures of 1250 and 1400°C in a drop tube furnace. The collected solid residues were structurally characterized by electron...

  11. Diagnostic development for determining the joint temperature/soot statistics in hydrocarbon-fueled pool fires : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Casteneda, Jaime N.; Frederickson, Kraig; Grasser, Thomas W.; Hewson, John C.; Kearney, Sean Patrick; Luketa, Anay Josephine

    2009-09-01

    A joint temperature/soot laser-based optical diagnostic was developed for the determination of the joint temperature/soot probability density function (PDF) for hydrocarbon-fueled meter-scale turbulent pool fires. This Laboratory Directed Research and Development (LDRD) effort was in support of the Advanced Simulation and Computing (ASC) program which seeks to produce computational models for the simulation of fire environments for risk assessment and analysis. The development of this laser-based optical diagnostic is motivated by the need for highly-resolved spatio-temporal information for which traditional diagnostic probes, such as thermocouples, are ill-suited. The in-flame gas temperature is determined from the shape of the nitrogen Coherent Anti-Stokes Raman Scattering (CARS) signature and the soot volume fraction is extracted from the intensity of the Laser-Induced Incandescence (LII) image of the CARS probed region. The current state of the diagnostic will be discussed including the uncertainty and physical limits of the measurements as well as the future applications of this probe.

  12. Laboratory Measurements of the Effect of Sulfuric and Organic Acid Coatings on the Optical Properties of Carbon Soot Aerosols

    Science.gov (United States)

    Xue, H.; Khalizov, A.; Zhang, R.

    2008-12-01

    Aerosol particles perturb the Earth-atmosphere radiative balance through scattering and absorption of the solar energy. Soot or black carbon, produced during combustion of fossil fuels and biofuels, is the major component responsible for light absorption by aerosol particles. The variation in the reported mass-specific absorption cross-sections (MAC) of fresh soot and increased light absorption by aged soot aerosols internally mixed with non-absorbing materials are the major factors leading to large uncertainties in the evaluation of the aerosol optical effects. We have investigated the optical properties of submicron carbon soot aerosols during simulated atmospheric processing with sulfuric acid and dicarboxylic organic acids. Internally mixed soot particles with known size, morphology, and the mixing state were produced by exposing the size-classified, flame-generated soot to sulfuric acid and organic acid vapor. Light extinction and scattering by fresh and internally mixed soot were measured at 532 nm wavelength using a cavity ring-down spectrometer and an integrating nephelometer, respectively; light absorption was derived as the difference between extinction and scattering. Mass-specific absorption cross-sections for fresh and internally mixed soot aggregates were calculated using the measured effective densities of soot cores. The optical properties of fresh soot were independent of the relative humidity (RH). Internally mixed soot exhibited significant enhancement in light absorption and scattering, increasing with the mass fraction of the coating material and RH. Sulfuric acid was found to cause greater enhancement in soot optical properties than organic acids. The higher absorption and scattering resulted in the increased single scattering albedo of coated soot aerosol. The measurements indicate that the irreversible restructuring of soot aggregates to more compact globules is a major contributor to the enhanced optical properties of internally mixed soot.

  13. Optical measurements of soot size and number density in a complex flow, swirl-stabilized combustor

    Science.gov (United States)

    Samuelsen, G. S.; Wood, C. P.; Jackson, T. A.

    1984-01-01

    In-flame optical measurements of soot particulates in a turbulent, recirculating (i.e., complex flow) model laboratory combustor are described. A nonintrusive optical probe based on large angle (60 deg, 20 deg) intensity ratio scattering was used to yield a point measurement of particulate in the size range of 0.08 to 0.38 micrometers. The performance of the optical technique was evaluated, and an exploratory assessment of the spatial distribution of soot was conducted with attention to fuel molecular structure, fuel loading, and a smoke-suppressant additive (ferrocene). Isooctane and mixtures of isooctane with various ring and aromatic compounds blended to yield the smoke point of a JP-8 stock were prevaporized and introduced through a hollow cone nozzle. The addition of ring compounds to the base isooctane substantially changed the distribution of soot and increased the overall emission by 300%. The production of soot was substantially reduced by a decrease in fuel loading, and marginally reduced or not affected by the additive depending on fuel structure. The optical technique is a potentially powerful tool for providing the experimental evidence necessary to understand the processes of soot formation and burnout in complex flows typical of gas turbine combustors. However, scanning electron micrographs of extracted sample established that the technique is limited to the large particle wing of the soot size distribution, and optical and electronic processing can induce biasing and uncertainties which must be understood and controlled before the potential of the technique can be fulfilled.

  14. Efficient low-temperature soot combustion by bimetallic Ag-Cu/SBA-15 catalysts.

    Science.gov (United States)

    Wen, Zhaojun; Duan, Xinping; Hu, Menglin; Cao, Yanning; Ye, Linmin; Jiang, Lilong; Yuan, Youzhu

    2018-02-01

    In this study, the effects of copper (Cu) additive on the catalytic performance of Ag/SBA-15 in complete soot combustion were investigated. The soot combustion performance of bimetallic Ag-Cu/SBA-15 catalysts was higher than that of monometallic Ag and Cu catalysts. The optimum catalytic performance was acquired with the 5Ag 1 -Cu 0.1 /SBA-15 catalyst, on which the soot combustion starts at T ig =225°C with a T 50 =285°C. The temperature for 50% of soot combustion was lower than that of conventional Ag-based catalysts to more than 50°C (Aneggi et al., 2009). Physicochemical characterizations of the catalysts indicated that addition of Cu into Ag could form smaller bimetallic Ag-Cu nanolloy particles, downsizing the mean particle size from 3.7nm in monometallic catalyst to 2.6nm in bimetallic Ag-Cu catalyst. Further experiments revealed that Ag and Cu species elicited synergistic effects, subsequently increasing the content of surface active oxygen species. As a result, the structure modifications of Ag by the addition of Cu strongly intensified the catalytic performance. Copyright © 2017. Published by Elsevier B.V.

  15. Laser-Diagnostic Mapping of Temperature and Soot Statistics in a 2-m Diameter Turbulent Pool Fire

    Science.gov (United States)

    Kearney, Sean

    2013-11-01

    We present spatial profiles of temperature and soot-volume-fraction statistics from a sooting 2-m base diameter turbulent pool fire. Dual-pump coherent anti-Stokes Raman scattering (CARS) and laser-induced incandescence (LII) are utilized to obtain profiles of temperature and soot probability density functions (pdf) at three vertical heights above the surface of the methanol/toluene fuel pool. The experiments are conducted in the unique Sandia FLAME facility, which has recently been modified to allow for vertical translation of the optical systems and horizontal translation of the liquid fuel burner. Results are presented both in the fuel vapor-dome region at 0.25 base diameter and in the actively burning region at 0.5 and 0.75 diameters above the fuel surface. The evolution of the soot and temperature pdfs is discussed, profiles of the temperature and soot mean and rms statistics are provided, and initial estimates of the joint temperature/soot statistics, which describe soot radiative emission, are presented.

  16. Dependence of soot optical properties on particle morphology: measurements and model comparisons.

    Science.gov (United States)

    Radney, James G; You, Rian; Ma, Xiaofei; Conny, Joseph M; Zachariah, Michael R; Hodges, Joseph T; Zangmeister, Christopher D

    2014-03-18

    We report the first mass-specific absorption and extinction cross sections for size- and mass-selected laboratory-generated soot aerosol. Measurement biases associated with aerosols possessing multiple charges were eliminated using mass selection to isolate singly charged particles for a specified electrical mobility diameter. Aerosol absorption and extinction coefficients were measured using photoacoustic and cavity ring-down spectroscopy techniques, respectively, for lacey and compacted soot morphologies. The measurements show that the mass-specific absorption cross sections are proportional to particle mass and independent of morphology, with values between 5.7 and 6 m(2) g(-1). Mass-specific extinction cross sections were morphology dependent and ranged between 12 and 16 m(2) g(-1) for the lacey and compact morphologies, respectively. The resulting single-scattering albedos ranged from 0.5 to 0.6. Results are also compared to theoretical calculations of light absorption and scattering from simulated particle agglomerates. The observed absorption is relatively well modeled, with minimum differences between the calculated and measured mass absorption cross sections ranging from ∼ 5% (lacey soot) to 14% (compact soot). The model, however, was unable to satisfactorily reproduce the measured extinction, underestimating the single-scattering albedo for both particle morphologies. These discrepancies between calculations and measurements underscore the need for validation and refinement of existing models of light scattering and absorption by soot agglomerates.

  17. Temperature measurement

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003400.htm Temperature measurement To use the sharing features on this page, please enable JavaScript. The measurement of body temperature can help detect illness. It can also monitor ...

  18. Soot Surface Growth in Laminar Hydrocarbon/Air Diffusion Flames. Appendix B

    Science.gov (United States)

    El-Leathy, A. M.; Xu, F.; Kim, C. H.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    The structure and soot surface growth properties of round laminar jet diffusion flames were studied experimentally. Measurements were made along the axes of ethylene-, propylene-propane- and acetylene-benzene-fueled flames burning in coflowing air at atmospheric pressure with the reactants at normal temperature. The measurements included soot structure, soot concentrations, soot temperatures, major gas species concentrations, some radial species (H, OH and O) concentrations, and gas velocities. These measurements yielded the local flame properties that are thought to affect soot surface growth as well as local soot surface growth rates. When present results were combined with similar earlier observations of acetylene-fueled laminar jet diffusion flames, the results suggested that soot surface growth involved decomposition of the original fuel to form acetylene and H, which were the main reactants for soot surface growth, and that the main effect of the parent fuel on soot surface growth involved its yield of acetylene and H for present test conditions. Thus, as the distance increased along the axes of the flames, soot formation (which was dominated by soot surface growth) began near the cool core of the flow once acetylene and H appeared together and ended near the flame sheet when acetylene disappeared. Species mainly responsible for soot oxidation - OH and O2 were present throughout the soot formation region so that soot surface growth and oxidation proceeded at the same time. Present measurements of soot surface growth rates (corrected for soot surface oxidation) in laminar jet diffusion flames were consistent with earlier measurements of soot surface growth rates in laminar premixed flames and exhibited good agreement with existing Hydrogen-Abstraction/Carbon-Addition (HACA) soot surface growth mechanisms in the literature with steric factors in these mechanisms having values on the order of unity, as anticipated.

  19. Soot Surface Growth in Laminar Hydrocarbon/Air Diffusion Flames. Appendix J

    Science.gov (United States)

    El-Leathy, A. M.; Xu, F.; Kim, C. H.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2003-01-01

    The structure and soot surface growth properties of round laminar jet diffusion flames were studied experimentally. Measurements were made along the axes of ethylene-, propylene-propane- and acetylene-benzene-fueled flames burning in coflowing air at atmospheric pressure with the reactants at normal temperature. The measurements included soot structure, soot concentrations, soot temperatures, major gas species concentrations, some radial species (H, OH and 0) concentrations, and gas velocities. These measurements yielded the local flame properties that are thought to affect soot surface growth as well as local soot surface growth rates. When present results were combined with similar earlier observations of acetylene-fueled laminar jet diffusion flames, the results suggested that soot surface growth involved decomposition of the original fuel to form acetylene and H, which were the main reactants for soot surface growth, and that the main effect of the parent fuel on soot surface growth involved its yield of acetylene and H for present test conditions. Thus, as the distance increased along the axes of the flames, soot formation (which was dominated by soot surface growth) began near the cool core of the flow once acetylene and H appeared together and ended near the flame sheet when acetylene disappeared. Species mainly responsible for soot oxidation - OH and 02 were present throughout the soot formation region so that soot surface growth and oxidation proceeded at the same time. Present measurements of soot surface growth rates (corrected for soot surface oxidation) in laminar jet diffusion flames were consistent with earlier measurements of soot surface growth rates in laminar premixed flames and exhibited good agreement with existing Hydrogen-Abstraction/Carbon-Addition (HACA) soot surface growth mechanisms in the literature with steric factors in these mechanisms having values on the order of unity, as anticipated.

  20. Soot particle size measurements in ethylene diffusion flames at elevated pressures

    KAUST Repository

    Steinmetz, Scott

    2016-05-07

    Soot particle size is investigated in laminar nitrogen-diluted ethylene coflow diffusion flames at 4, 8, 12 and 16 atm. Line of sight attenuation and scattering are used to measure two-dimensional soot volume fraction and particle size fields for the first time at elevated pressures. Soot volume fraction dependence on pressure is consistent with the observations of similar studies, scaling approximately with the square of pressure. Scattering intensity is analyzed through Rayleigh and Rayleigh-Debye-Gans polydisperse fractal aggregate theories to provide two estimates of particle size. An increase in overall particle sizes with pressure is found, consistent with similar one-dimensional studies. Particle diameters in the annulus of the flame increase faster with pressure than those on centerline. Contrary to previous studies, the dependence of particle size on pressure was found to taper off between 8 and 12 atm, with little observed growth beyond 12 atm. The measurements provide additional data for one of the International Sooting Flame (ISF) workshop\\'s target pressurized flames.

  1. Tailored graphitized soot as reference material for EC/OC measurement validation

    Directory of Open Access Journals (Sweden)

    O. Popovicheva

    2011-05-01

    Full Text Available The lack of standard reference materials for calibrating, troubleshooting and intercomparing techniques that measure the composition of black carbon, commonly referred to as soot, has been a major obstacle that hinders improved understanding of how climate and health is impacted by this ubiquitous component of the atmosphere. A different approach is offered here as a means of constructing precisely controlled material with fractions of organic carbon (OC on the surface of elemental carbon (EC whose structure reflects that of the combustion produced particles found in the atmosphere. The proposed soot reference material (SRM uses EC as a basis substrate for surface coatings of organic compounds that are representative of the main classes of organics identified in the coverage of soot produced by fossil fuel burning. A number of methods are used to demonstrate the quality and stability of the reference EC and SRM. Comparison of the nominal fraction of OC deposited on the EC substrate with the fraction measured with thermal/optical analysis (TOA shows excellent agreement. Application of this type of reference material for evaluating the different methods of carbon analysis may help resolve differences that currently exist between comparable measurement techniques when trying to separate OC and EC from ambient samples.

  2. Effects of several types of biomass fuels on the yield, nanostructure and reactivity of soot from fast pyrolysis at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Jensen, Peter Arendt; Jensen, Anker Degn

    2016-01-01

    This study presents the effect of biomass origin on the yield, nanostructure and reactivity of soot. Soot was produced from wood and herbaceous biomass pyrolysis at high heating rates and at temperatures of 1250 and 1400 °C in a drop tube furnace. The structure of solid residues was characterized...

  3. Potassium and soot interaction in fast biomass pyrolysis at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Hofmann Larsen, Flemming; Shchukarev, Andrey

    2018-01-01

    This study aims to investigate the interaction between potassium and carbonaceous matrix of soot produced from wood and herbaceous biomass pyrolysis at high heating rates at 1250°C in a drop tube reactor. The influence of soot carbon chemistry and potassium content in the original biomass on the CO...

  4. Improved soot blowing, based on needs, through measurement of the natural frequency of the heat transferring tubes; Foerbaettrad behovsstyrd sotning genom maetning av oeverfoerande tubernas egenfrekvens

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Elisabet; Ivarsson, Christofer

    2007-11-15

    The aim of the project is to develop a method for detecting soot on the transferring tubes by measuring the Eigen frequency of the tubes as a function of the soot deposit growth. The project is a pilot study independent of boiler type and it is applicable to all boilers where soot deposit on transferring tubes is a repeating issue. The report is supposed to answer two major questions. Is it possible to make use of Eigen frequencies in order to trace soot deposit on transferring tubes? What governing parameters are related to the Eigen frequency of transferring tubes? By today, soot blowing is executed after recommendations from the manufacturer in terms of number of soot blowing per time unit. The fuel type as well as boiler type has great influence on the soot deposit growth. The objective of the project is to investigate whether the mechanical properties of the transferring tube can be used to detect soot deposit. The project is divided into a theoretical and a practical part. The theoretical part covers the design of the probe and the change of its mechanical properties when soot deposit is present. Practical experiments were then carried out in a laboratory were the probes mechanical properties with and without soot deposit were investigated. It was shown that the Eigen frequency of the probe decreased with an increased mass due to soot deposit. A test was also made in a boiler at SAKAB but difficulties in attaching the probe to the inspection hatch. The results varied and the interpretation of the results become difficult. However, it was obvious that the mechanical properties of the probe changed with the amount of soot deposit. It was concluded that detection of soot deposit by studying the mechanical properties of the transferring tubes is possible. Yet, using a probe is no optimal solution, instead measurements should be done directly on the heat transferring tubes. In addition, a strategy for controlling the soot deposit has to be developed

  5. Arctic tundra shrub invasion and soot deposition: Consequences for spring snowmelt and near-surface air temperatures

    Science.gov (United States)

    Strack, John E.; Pielke, Roger A.; Liston, Glen E.

    2007-12-01

    Invasive shrubs and soot pollution both have the potential to alter the surface energy balance and timing of snow melt in the Arctic. Shrubs reduce the amount of snow lost to sublimation on the tundra during the winter leading to a deeper end-of-winter snowpack. The shrubs also enhance the absorption of energy by the snowpack during the melt season by converting incoming solar radiation to longwave radiation and sensible heat. Soot deposition lowers the albedo of the snow, allowing it to more effectively absorb incoming solar radiation and thus melt faster. This study uses the Colorado State University Regional Atmospheric Modeling System version 4.4 (CSU-RAMS 4.4), equipped with an enhanced snow model, to investigate the effects of shrub encroachment and soot deposition on the atmosphere and snowpack in the Kuparuk Basin of Alaska during the May-June melt period. The results of the simulations suggest that a complete invasion of the tundra by shrubs leads to a 2.2°C warming of 3 m air temperatures and a 108 m increase in boundary layer depth during the melt period. The snow-free date also occurred 11 d earlier despite having a larger initial snowpack. The results also show that a decrease in the snow albedo of 0.1, owing to soot pollution, caused the snow-free date to occur 5 d earlier. The soot pollution caused a 1.0°C warming of 3 m air temperatures and a 25 m average deepening of the boundary layer.

  6. Size-resolved measurement of the mixing state of soot in the megacity Beijing, China: Diurnal cycle, aging and parameterization

    Science.gov (United States)

    Cheng, Y. F.; Su, H.; Rose, D.; Gunthe, S. S.; Berghof, M.; Wehner, B.; Achtert, P.; Nowak, A.; Takegawa, N.; Kondo, Y.; Shiraiwa, M.; Gong, Y. G.; Shao, M.; Hu, M.; Zhu, T.; Zhang, Y. H.; Wiedensohler, A.; Andreae, M. O.; Pöschl, U.

    2013-05-01

    In the summer of 2006, measurements of the mixing state of non-volatile particles were carried out at a suburban site of Beijing in the North China Plain by using a VTDMA. In this study, we perform an in-depth analysis of VTDMA results, focusing on the following topics: (1) comparison of the mixing state of soot measured by a VTDMA and the aerosol hygroscopicity mixing state determined by a CCN (cloud condensation nuclei) counter; (2) diurnal variation and evolution of soot mixing state at different size ranges; (3) calculation of kex→in and the influence of emissions on it; and (4) potential parameterization methods.

  7. Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

    KAUST Repository

    Jing, Wei

    2016-12-01

    Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel, however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.

  8. A computational study of radiation and gravity effect on temperature and soot formation in a methane air co-flow diffusion flame

    Energy Technology Data Exchange (ETDEWEB)

    Bhowal, Arup Jyoti, E-mail: arupjyoti.bhowal@heritageit.edu [Department of Mechanical Engineering, Heritage Institute of Technology, Chowbaga Road, Anandapur, Kolkata-700 107, West Bengal (India); Mandal, Bijan Kumar, E-mail: bkm375@yahoo.co.in [Department of Mechanical Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah – 711103, West Bengal (India)

    2016-07-12

    An effort has been made for a quantitative assessment of the soot formed under steady state in a methane air co flow diffusion flame by a numerical simulation at normal gravity and at lower gravity levels of 0.5 G, 0.1 G and 0.0001 G (microgravity). The peak temperature at microgravity is reduced by about 50 K than that at normal gravity level. There is an augmentation of soot formation at lower gravity levels. Peak value at microgravity multiplies by a factor of ∼7 of that at normal gravity. However, if radiation is not considered, soot formation is found to be much more.

  9. Size-resolved measurement of the mixing state of soot in the megacity Beijing, China: diurnal cycle, aging and parameterization

    Directory of Open Access Journals (Sweden)

    Y. F. Cheng

    2012-05-01

    Full Text Available Soot particles are the most efficient light absorbing aerosol species in the atmosphere, playing an important role as a driver of global warming. Their climate effects strongly depend on their mixing state, which significantly changes their light absorbing capability and cloud condensation nuclei (CCN activity. Therefore, knowledge about the mixing state of soot and its aging mechanism becomes an important topic in the atmospheric sciences.

    The size-resolved (30–320 nm diameter mixing state of soot particles in polluted megacity air was measured at a suburban site (Yufa during the CAREBeijing 2006 campaign in Beijing, using a volatility tandem differential mobility analyzer (VTDMA. Particles in this size range with non-volatile residuals at 300 °C were considered to be soot particles. On average, the number fraction of internally mixed soot in total soot particles (Fin, decreased from 0.80 to 0.57 when initial Dp increased from 30 to 320 nm. Further analysis reveals that: (1 Fin was well correlated with the aerosol hygroscopic mixing state measured by a CCN counter. More externally mixed soot particles were observed when particles showed more heterogeneous features with regard to hygroscopicity. (2 Fin had pronounced diurnal cycles. For particles in the accumulation mode (Dp at 100–320 nm, largest Fin were observed at noon time, with "apparent" turnover rates (kex → in up to 7.8% h−1. (3 Fin was subject to competing effects of both aging and emissions. While aging increases Fin by converting externally mixed soot particles into internally mixed ones, emissions tend to reduce Fin by emitting more fresh and externally mixed soot particles. Similar competing effects were also found with air mass age indicators. (4 Under the estimated emission

  10. Correlation of Soot Formation in Turbojet Engines and in Laboratory Flames.

    Science.gov (United States)

    1981-02-01

    tendency of a fuel to soot (cf. Refs. 18 and 19); for Bunsen burner flames the calculated adiabatic flame temperatures at the incipient soot point... flame burner is used to measure the smoke point. An objection can also be made to using a smoke point defined by using small laboratory diffusion...in Appendix A, it is possible to calibrate a wide variety of laboratory-scale diffusion or premixed flame burners so that if soot thresh- olds for a

  11. Effect of Dimethyl Ether Mixing on Soot Size Distribution in Premixed Ethylene Flame

    KAUST Repository

    Li, Zepeng

    2016-04-21

    As a byproduct of incomplete combustion, soot attracts increasing attentions as extensive researches exploring serious health and environmental effects from soot particles. Soot emission reduction requires a comprehensive understanding of the mechanism for polycyclic aromatic hydrocarbons and of soot formation and aging processes. Therefore, advanced experimental techniques and numerical simulations have been conducted to investigate this procedure. In order to investigate the effects of dimethyl ether (DME) mixing on soot particle size distribution functions (PSDFs), DME was mixed in premixed ethylene/oxygen/argon at flames at the equivalence ratio of 2.0 with a range of mixing ratio from 0% to 30% of the total carbon fed. Two series of atmospheric pressure flames were tested in which cold gas velocity was varied to obtain different flame temperatures. The evolution of PSDFs along the centerline of the flame was determined by burner stabilized stagnation probe and scanning mobility particle sizer (SMPS) techniques, yielding the PSDFs for various separation distances above the burner surface. Meanwhile, the flame temperature profiles were carefully measured by a thermocouple and the comparison to that of simulated laminar premixed burner-stabilized stagnation flame was satisfactory. Additionally, to understand the chemical role of DME mixing in soot properties, characterization measurements were conducted on soot samples using thermo-gravimetric analysis (TGA) and elemental analysis (EA). Results of the evolution of PSDFs and soot volume fraction showed that adding DME into ethylene flame could reduce soot yield significantly. The addition of DME led to the decrease of both the soot nucleation rate and the particle mass growth rate. To explain the possible mechanism for the observation, numerical simulations were performed. Although DME addition resulted in the slight increase of methyl radicals from pyrolysis, the decrease in acetylene and propargyl radicals

  12. Soot Formation in Laminar Premixed Methane/Oxygen Flames at Atmospheric Pressure

    Science.gov (United States)

    Xu, F.; Lin, K.-C.; Faeth, G. M.

    1998-01-01

    Flame structure and soot formation were studied within soot-containing laminar premixed mc1hane/oxygen flames at atmospheric pressure. The following measurements were made: soot volume fractions by laser extinction, soot temperatures by multiline emission, gas temperatures (where soot was absent) by corrected fine-wire thermocouples, soot structure by thermophoretic sampling and transmission electron microscope (TEM), major gas species concentrations by sampling and gas chromatography, and gas velocities by laser velocimetry. Present measurements of gas species concentrations were in reasonably good agreement with earlier measurements due to Ramer et al. as well as predictions based on the detailed mechanisms of Frenklach and co-workers and Leung and Lindstedt: the predictions also suggest that H atom concentrations are in local thermodynamic equilibrium throughout the soot formation region. Using this information, it was found that measured soot surface growth rates could be correlated successfully by predictions based on the hydrogen-abstraction/carbon-addition (HACA) mechanisms of both Frenklach and co-workers and Colket and Hall, extending an earlier assessment of these mechanisms for premixed ethylene/air flames to conditions having larger H/C ratios and acetylene concentrations. Measured primary soot particle nucleation rates were somewhat lower than the earlier observations for laminar premixed ethylene/air flames and were significantly lower than corresponding rates in laminar diffusion flames. for reasons that still must be explained.

  13. Comparison of soot formation for diesel and jet-a in a constant volume combustion chamber using two-color pyrometry

    KAUST Repository

    Jing, Wei

    2014-04-01

    The measurement of the two-color line of sight soot and KL factor for NO.2 diesel and jet-A fuels was conducted in an optical constant volume combustion chamber by using a high speed camera under 1000 K ambient temperature and varied oxygen concentration conditions. The ambient conditions were set as follows: four oxygen cases including 10%, 15%, 18% and 21% at 1000 K ambient temperature. KL factor and soot temperature were determined based on the two-color pyrometry technique using two band-pass filters with wavelengths of 650 nm and 550 nm. The results show that low soot temperature is observed in the upstream inner flame along the centerline, which is surrounded by high soot temperature regions, and a high KL factor is found in the same region with a low soot temperature. The results under different times suggest that soot temperature is higher for high O2 conditions during the entire flame development; meanwhile, both integrated KL factor and soot area decrease with the increase of O2 concentration. The two fuels share a similar trend of soot temperature and KL factor, however, diesel flame has a higher soot temperature and a larger high soot temperature area compared to jet-A flame. On the other hand, diesel flame shows a lower soot level during the quasi-steady state with a higher total soot level at the end of the combustion under low O2 conditions. A lower O2 concentration range from 10% to 15% is expected to have the possibility to achieve a simultaneous reduction of soot and NOx in sooting flames under the 1000 K ambient temperature condition. Copyright © 2014 SAE International.

  14. Computational Investigation of Soot and Radiation in Turbulent Reacting Flows

    Science.gov (United States)

    Lalit, Harshad

    This study delves into computational modeling of soot and infrared radiation for turbulent reacting flows, detailed understanding of both of which is paramount in the design of cleaner engines and pollution control. In the first part of the study, the concept of Stochastic Time and Space Series Analysis (STASS) as a numerical tool to compute time dependent statistics of radiation intensity is introduced for a turbulent premixed flame. In the absence of high fidelity codes for large eddy simulation or direct numerical simulation of turbulent flames, the utility of STASS for radiation imaging of reacting flows to understand the flame structure is assessed by generating images of infrared radiation in spectral bands dominated by radiation from gas phase carbon dioxide and water vapor using an assumed PDF method. The study elucidates the need for time dependent computation of radiation intensity for validation with experiments and the need for accounting for turbulence radiation interactions for correctly predicting radiation intensity and consequently the flame temperature and NOx in a reacting fluid flow. Comparison of single point statistics of infrared radiation intensity with measurements show that STASS can not only predict the flame structure but also estimate the dynamics of thermochemical scalars in the flame with reasonable accuracy. While a time series is used to generate realizations of thermochemical scalars in the first part of the study, in the second part, instantaneous realizations of resolved scale temperature, CO2 and H2O mole fractions and soot volume fractions are extracted from a large eddy simulation (LES) to carry out quantitative imaging of radiation intensity (QIRI) for a turbulent soot generating ethylene diffusion flame. A primary motivation of the study is to establish QIRI as a computational tool for validation of soot models, especially in the absence of conventional flow field and measured scalar data for sooting flames. Realizations of

  15. Role of Fluid-Dynamics in Soot Formation and Microstructure in Acetylene-Air Laminar Diffusion Flames

    Directory of Open Access Journals (Sweden)

    Praveen Pandey

    2015-03-01

    Full Text Available Residence time and thermo-chemical environment are important factors in the soot-formation process in flames. Studies have revealed that flow-dynamics plays a dominant role in soot formation process. For understanding the effect of flow dynamics on soot formation and physical structure of the soot formed in different combustion environments two types of laminar diffusion flames of Acetylene and air, a normal diffusion flame (NDF and an inverse diffusion flame (IDF have been investigated. The fuel and air supply in the reaction zone in two flame types were kept constant but the interchange of relative position of fuel and air altered the burner exit Reynolds and Froude numbers of gases, fuel/air velocity ratio and flame shape. Soot samples were collected using thermophoretic sampling on transmission electron microscope (TEM grids at different flame heights and were analyzed off-line in a Transmission Electron Microscope. Soot primary particle size, soot aggregate size and soot volume fraction were measured using an image analysis software. In NDF the maximum flame temperature was about 1525 K and 1230 K for IDF. The soot primary particles are distinctly smaller in size in IDF (between 19 – 26 nm compared to NDF (between 29–34 nm. Both NDF and IDF show chainlike branched structure of soot agglomerate with soot particles of a nearly spherical shape. The average number of soot primary particles per aggregate in NDF was in the range of 24 to 40 and in IDF it varied between 16 to 24. Soot volume fraction was between 0.6 to 1.5 ppm in NDF where as it was less than 0.2 ppm in IDF. The change in sooting characteristics of the two flame types is attributed to changed fuel/air velocity ratio, entrainment of gas molecules and thermophoresis on soot particles.

  16. Effects of Lignocellulosic Compounds on the Yield, Nanostructure and Reactivity of Soot from Fast Pyrolysis at High Temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Broström, Markus; Kling, Jens

    a possible plant shut down. The reduction of soot formation increases the overall production system efficiency and improves the economic feasibility and reliability of the gasification plant. Soot from biomass pyrolysis contains greater inherent oxygen functionalities than hydrocarbons soot and adsorbs...... primary, secondary and teriary pyrolysis products such as organic acids, aldehydes and phenolics [1]. In this study, therefore, the impacts of lignocellulosic compounds and monolignols (syringol, guaiacol, p-hydroxyphenol) on the yield and characteristics of soot were investigated at 1250°C in a drop tube...

  17. Soot measurements by two angle scattering and extinction in an N 2 -diluted ethylene/air counterflow diffusion flame from 2 to 5 atm

    KAUST Repository

    Amin, Hafiz M.F.

    2016-06-27

    The soot formed in an N-diluted ethylene/air counterflow diffusion flame at elevated pressure was investigated using two angle light scattering/extinction technique. To provide a well-controlled pressurized environment for the flame, a novel pressure vessel was built with the required optical access. The soot parameters were measured along the centerline of the counterflow flame. These properties included soot volume fraction (f ), primary particle diameter (d ), population averaged radius of gyration (R ) and number density of primary particles (n ). The Rayleigh-Debye-Gans theory for Fractal Aggregates (RDG-FA) was used to retrieve these properties from scattering and extinction measurements. Soot volume fraction was measured via light extinction from 2 to 5atm while maintaining the same global strain rate at all pressures. Scattered light from soot particles was measured at 45° and 135° and primary particle diameter was calculated using scattering/extinction ratio and the radius of gyration was determined from the dissymmetry ratio. Soot volume fraction, primary particle diameter and radius of gyration all increased with pressure while the number density of primary particles decreased with increasing pressure.

  18. Uptake of HNO3 on hexane and aviation kerosene soots.

    Science.gov (United States)

    Talukdar, Ranajit K; Loukhovitskaya, Ekaterina E; Popovicheva, Olga B; Ravishankara, A R

    2006-08-10

    The uptake of HNO(3) on aviation kerosene (TC-1) soot was measured as a function of temperature (253-295 K) and the partial pressure of HNO(3), and the uptake of HNO(3) on hexane soot was studied at 295 K and over a limited partial pressure of HNO(3). The HNO(3) uptake was mostly reversible and did not release measurable amounts of gas-phase products such as HONO, NO(3), NO(2) or N(2)O(5). The heat of adsorption of HNO(3) on soot was dependent on the surface coverage. The isosteric heats of adsorption, Delta(0)H(isosteric), were determined as a function of coverage. Delta(0)H(isosteric) values were in the range -16 to -13 kcal mol(-1). The heats of adsorption decrease with increasing coverage. The adsorption data were fit to Freundlich and to Langmuir-Freundlich isotherms. The heterogeneity parameter values were close to 0.5, which suggested that a HNO(3) molecule can occupy two sites on the surface with or without being dissociated and that the soot surface could be nonuniform. Surface FTIR studies on the interaction of soot with HNO(3) did not reveal formation of any minor product such as organic nitrate or nitro compound on the soot surface. Using our measured coverage, we calculate that the partitioning of gas-phase nitric acid to black carbon aerosol is not a significant loss process of HNO(3) in the atmosphere.

  19. Equipment for temperature measurements

    OpenAIRE

    HORELICA, Josef

    2008-01-01

    This work deals with theoretical description, practical connection of temperature measuring instruments and how they function while measuring the temperature. This document explaines basic concepts of temperature, temperature scales and temperature measuring. Further there are introduced standard types of sensors used in these measuring intruments. This document includes a picture presentation in PowerPoint, where an aggregate table of sensors and an application of these sensors in measuring ...

  20. Polynuclear aromatic hydrocarbon and particulate emissions from two-stage combustion of polystyrene: the effects of the secondary furnace (afterburner) temperature and soot filtration.

    Science.gov (United States)

    Wang, Jun; Richter, Henning; Howard, Jack B; Levendis, Yiannis A; Carlson, Joel

    2002-02-15

    converted into soot, while the total mass of PAH represented about 3% of the initial mass of combustible. The afterburner reduced the particulate (soot) emissions by only 20-30%, which indicates that once soot is formed its destruction is rather difficult because its oxidation kinetics are slow undertypical furnace conditions. Moreover, increasing the afterburnertemperature resulted in an increasing trend of soot emissions therefrom, which might indicate competition between soot oxidation and formation, with some additional formation occurring at the higher temperatures. Contrary to the limited effect of the afterburner, high-temperature filtration of the combustion effluent prior to the exit of the primary furnace allowed for effective soot oxidation inside of the ceramic filter. Filtration drastically reduced soot emissions, by more than 90%. Limited soot formation in the afterburner was again observed with increasing temperatures. The yields of both CO and CO2 were largely unaffected by the temperature of the afterburner but increased at the presence of the filter indicating oxidation therein. A previously developed kinetic model was used to identify major chemical reaction pathways involving PAH in the afterburner. The experimental data at the exit of the primary furnace was used as input to these model computations. A first evaluation of the predictive capability of the model was conducted for the case with ceramic filter and a temperature of 900 degrees C. The afterburner was approximated as a plug-flow reactor, and model predictions at a residence time of 0.8 s were compared to experimental data collected at its exit. In agreement with the experimental PAH concentration, only a minor impact of the afterburner treatment was observed for most species at 900 degrees C. OH was deduced to be the major reactant with a mole fraction about 4 orders of magnitudes higher than that of hydrogen radicals. Evidence for the need of further work on the quantitative assessment of

  1. Detection of Soot Using a Resistivity Sensor Device Employing Thermophoretic Particle Deposition

    Directory of Open Access Journals (Sweden)

    Doina Lutic

    2010-01-01

    Full Text Available Results are reported for thermophoretic deposition of soot particles on resistivity sensors as a monitoring technique for diesel exhaust particles with the potential of improved detection limit and sensitivity. Soot with similar characteristics as from diesel exhausts was generated by a propane flame and diluted in stages. The soot in a gas flow at 240–270C∘ was collected on an interdigitated electrode structure held at a considerably lower temperature, 105–125C∘. The time delay for reaching measurable resistance values, the subsequent rate, and magnitude of resistance decrease were a function of the distance between the fingers in the electrodes and the degree of dilution of the soot containing flow. Soot deposition and subsequent removal by heating the sensor support was also performed in a real diesel exhaust. Good similarities between the behavior in our laboratory system and the real diesel exhaust were noticed.

  2. Investigations of the long-term effects of LII on soot and bath gas

    KAUST Repository

    Cenker, Emre

    2017-08-24

    A combination of high-repetition rate imaging, laser extinction measurements, two-colour soot pyrometry imaging, and high-resolution transmission electron microscopy of thermophoretically sampled soot is used to investigate the long-term and permanent effects of rapid heating of in-flame soot during laser-induced incandescence (LII). Experiments are carried out on a laminar non-premixed co-annular ethylene/air flame with various laser fluences. The high-repetition rate images clearly show that the heated and the neighbouring laser-border zones undergo a permanent transformation after the laser pulse, and advect vertically with the flow while the permanent marking is preserved. The soot volume fraction at the heated zone reduces due to the sublimation of soot and the subsequent enhanced oxidation. At the laser-border zones, however, optical thickness increases that may be due to thermophoretic forces drawing hot particles towards relatively cooler zones and the rapid compression of the bath gas induced by the pressure waves created by the expansion of the desorbed carbon clusters. Additionally sublimed carbon clusters can condense onto existing particles and contribute to increase of the optical thickness. Time-resolved two-colour pyrometry imaging show that the increased temperature of soot both in the heated and neighbouring laser-border zones persists for several milliseconds. This can be associated to the increase in the bath-gas temperature, and a change in the wavelength-dependent emissivity of soot particles induced by the thermal annealing of soot. Ex-situ analysis show that the lattice structure of the soot sampled at the laser-border zones tend to change and soot becomes more graphitic. This may be attributed to thermal annealing induced by elevated temperature.

  3. Numerical simulation of combustion and soot under partially premixed combustion of low-octane gasoline

    KAUST Repository

    An, Yanzhao

    2017-09-23

    In-cylinder combustion visualization and engine-out soot particle emissions were investigated in an optical diesel engine fueled with low octane gasoline. Single injection strategy with an early injection timing (−30 CAD aTDC) was employed to achieve partially premixed combustion (PPC) condition. A high-speed color camera was used to record the combustion images for 150 cycles. The regulated emission of carbon dioxide, carbon monoxide, nitrogen oxides and soot mass concentration were measured experimentally. Full cycle engine simulations were performed using CONVERGE™ and the simulation results matched with the experimental results. The in-cylinder soot particle evolution was performed by coupling a reduced toluene reference fuel mechanism including the PAHs formation/oxidation reactions with particulate size mimic model. The results showed that PPC presents typical stratified combustion characteristics, which is significantly different from the conventional diesel spray-driven combustion. The in-cylinder temperature and equivalence ratio overlaid with soot-NO formation regime revealed that PPC operating condition under study mostly avoided the main sooting conditions throughout the entire combustion. The evaluation of temperature distribution showed formaldehyde could be regarded as an indicator for low temperature reactions, while hydroxyl group represents the high temperature reactions. Soot evolution happened during the combustion process, hydroxyl radicals promoted the soot oxidation.

  4. Investigation of optical properties of aging soot

    Science.gov (United States)

    Migliorini, F.; Thomson, K. A.; Smallwood, G. J.

    2011-08-01

    The optical properties of soot, in particular the propensity of soot to absorb and scatter light as a function of wavelength, are key parameters for the correct interpretation of soot optical diagnostics. An overview of the data available in the literature highlights the differences in the reported optical properties of aging soot. In many cases, the properties of mature soot are used when evaluating in-flame soot but this assumption might not be suitable for all conditions and should be checked. This need has been demonstrated by performed spectral resolved line-of-sight attenuation (Spec-LOSA) measurements on an ethylene/air premixed and non-premixed flame. Transmission electron microscopy of thermophoretically sampled soot was also performed to qualify the soot aging and to establish soot morphology in order to correct light extinction coefficients for the scattering contribution. The measured refractive index absorption function, E( m) λ , showed a very strong spectral dependence which also varied with height above the burner for both flames. However, above 700 nm, the slope of the refractive index function was near zero for both flames and all measurement heights. The upper visible and near infrared wavelengths are therefore recommended for soot optical measurements.

  5. Understanding and predicting soot generation in turbulent non-premixed jet flames.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hai (University of Southern California, Los Angeles, CA); Kook, Sanghoon; Doom, Jeffrey; Oefelein, Joseph Charles; Zhang, Jiayao; Shaddix, Christopher R.; Schefer, Robert W.; Pickett, Lyle M.

    2010-10-01

    This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a strong impact on the rate of soot nucleation and particle coagulation, but little sensitivity in the overall trends was found with different fuels. An extensive array of non-intrusive optical and laser-based measurements was performed in turbulent non-premixed jet flames established on specially designed piloted burners. Soot concentration data was collected throughout the flames, together with instantaneous images showing the relationship between soot and the OH radical and soot and PAH. A detailed chemical kinetic mechanism for ethylene combustion, including fuel-rich chemistry and benzene formation steps, was compiled, validated, and reduced. The reduced ethylene mechanism was incorporated into a high-fidelity LES code, together with a moment-based soot model and models for thermal radiation, to evaluate the ability of the chemistry and soot models to predict soot formation in the jet diffusion flame. The LES results highlight the importance of including an optically-thick radiation

  6. Technical Note: The single particle soot photometer fails to reliably detect PALAS soot nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Gysel

    2012-12-01

    Full Text Available The single particle soot photometer (SP2 uses laser-induced incandescence (LII for the measurement of atmospheric black carbon (BC particles. The BC mass concentration is obtained by combining quantitative detection of BC mass in single particles with a counting efficiency of 100% above its lower detection limit. It is commonly accepted that a particle must contain at least several tenths of a femtogram BC in order to be detected by the SP2.

    Here we show the result that most BC particles from a PALAS spark discharge soot generator remain undetected by the SP2, even if their BC mass, as independently determined with an aerosol particle mass analyser (APM, is clearly above the typical lower detection limit of the SP2. Comparison of counting efficiency and effective density data of PALAS soot with flame generated soot (combustion aerosol standard burner, CAST, fullerene soot and carbon black particles (Cabot Regal 400R reveals that particle morphology can affect the SP2's lower detection limit. PALAS soot particles are fractal-like agglomerates of very small primary particles with a low fractal dimension, resulting in a very low effective density. Such loosely packed particles behave like "the sum of individual primary particles" in the SP2's laser. Accordingly, most PALAS soot particles remain undetected as the SP2's laser intensity is insufficient to heat the primary particles to their vaporisation temperature because of their small size (Dpp ≈ 5–10 nm. Previous knowledge from pulsed laser-induced incandescence indicated that particle morphology might have an effect on the SP2's lower detection limit, however, an increase of the lower detection limit by a factor of ∼5–10, as reported here for PALAS soot, was not expected.

    In conclusion, the SP2's lower detection limit at a certain laser power depends primarily on the total BC mass per particle for compact particles with sufficiently high effective

  7. High-throughput approach to the catalytic combustion of diesel soot

    Energy Technology Data Exchange (ETDEWEB)

    Iojoiu, Eduard Emil; Bassou, Badr; Guilhaume, Nolven; Farrusseng, David; Desmartin-Chomel, Arnold; Bianchi, Daniel; Mirodatos, Claude [Institut de recherches sur la catalyse et l' environnement de Lyon IRCELYON, UMR5256 CNRS Universite Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne Cedex (France); Lombaert, Karine [Renault, Diesel Innovative Catalytic Materials, Direction de l' Ingenierie Materiaux, 1 Allee Cornuel, 91510 Lardy (France)

    2008-08-30

    A methodology for the evaluation of diesel soot oxidation catalysts by high-throughput (HT) screening was developed. The optimal experimental conditions (soot amount, catalyst/soot ratio, type of contact, composition and flow rate of gas reactants) ensuring a reliable and reproducible detection of light-off temperatures in a 16 parallel channels reactor were set up. The temperature profile measured in the catalyst/soot bed under TPO conditions when the exothermic combustion of soot takes place was shown to provide an accurate measurement of the ignition. Its reproducibility and relevance were checked. The results obtained with a reference noble metal free catalyst (La{sub 0.8}Cr{sub 0.8}Li{sub 0.2}O{sub 3} perovskite) agree very well with literature data. Qualitative mechanistic features could be derived from these experiments, stressing the likely limiting step of oxygen transfer from catalyst surface to soot particulates to ignite the soot combustion. Ceria material was shown to be more appropriate than perovskite one. From an HT screening of a large diverse library (over 100 mixed oxides catalysts) under optimized conditions, about 10 new formulations were found to perform better than selected noble metal free reference materials. (author)

  8. Evaluation and optimisation of phenomenological multi-step soot model for spray combustion under diesel engine-like operating conditions

    Science.gov (United States)

    Pang, Kar Mun; Jangi, Mehdi; Bai, Xue-Song; Schramm, Jesper

    2015-05-01

    In this work, a two-dimensional computational fluid dynamics study is reported of an n-heptane combustion event and the associated soot formation process in a constant volume combustion chamber. The key interest here is to evaluate the sensitivity of the chemical kinetics and submodels of a semi-empirical soot model in predicting the associated events. Numerical computation is performed using an open-source code and a chemistry coordinate mapping approach is used to expedite the calculation. A library consisting of various phenomenological multi-step soot models is constructed and integrated with the spray combustion solver. Prior to the soot modelling, combustion simulations are carried out. Numerical results show that the ignition delay times and lift-off lengths exhibit good agreement with the experimental measurements across a wide range of operating conditions, apart from those in the cases with ambient temperature lower than 850 K. The variation of the soot precursor production with respect to the change of ambient oxygen levels qualitatively agrees with that of the conceptual models when the skeletal n-heptane mechanism is integrated with a reduced pyrene chemistry. Subsequently, a comprehensive sensitivity analysis is carried out to appraise the existing soot formation and oxidation submodels. It is revealed that the soot formation is captured when the surface growth rate is calculated using a square root function of the soot specific surface area and when a pressure-dependent model constant is considered. An optimised soot model is then proposed based on the knowledge gained through this exercise. With the implementation of optimised model, the simulated soot onset and transport phenomena before reaching quasi-steady state agree reasonably well with the experimental observation. Also, variation of spatial soot distribution and soot mass produced at oxygen molar fractions ranging from 10.0 to 21.0% for both low and high density conditions are reproduced.

  9. Ice Formation by Soot-Containing Aerosol Particles

    Science.gov (United States)

    Demott, P. J.; Petters, M. D.; Prenni, A. J.; Kreidenweis, S. M.; Carrico, C. M.; Bennett, M. R.; Stanglmaier, R.; Volckens, J.; Popovicheva, O. B.

    2006-12-01

    A role for soot particles as atmospheric ice forming nuclei remains highly uncertain and poorly quantified. A relatively small amount of data exists and most of this is for laboratory surrogates that may not be well characterized or of assured relevance to the atmosphere. It is important to constrain the role of soot particles as ice nuclei due to their abundance in the atmosphere and the large contribution from anthropogenic activities. Further, global climate models are beginning to be capable of treating the impact of different aerosol types, including soot particles. This paper reports on studies of ice formation by or within surrogates for hydrophobic soot and realistic carbonaceous particles from combustion of fuel in a diesel engine, burning of an assortment biomass materials, and real jet fuel combustor particles. Measurements of primarily monodisperse particles were focused below -30°C to emphasize the transition between temperatures where heterogeneous ice nucleation is required for ice formation and those for which homogeneous freezing processes are also possible. Ice nucleation measurements were made with a continuous flow diffusion chamber. Simultaneous measurements of hygroscopic water uptake and cloud condensation nucleation behavior were also made at 30°C for each aerosol type. Small fractions of hydrophobic soot particles are found capable of initiating heterogeneous ice formation at low temperatures. Results of studies of more realistic particles suggest that any process that increases hygroscopicity tends to limit the conditions for ice formation within soot particles. Most biomass burning particles, showing a range of dry/wet diameter hygroscopic growth factors (1.03 activity as CCN to 102% RH, yet behaved as particles containing solutions in which homogeneous freezing was supported at temperatures below -38°C. This is tentatively attributed to condensation of semi-volatiles during cooling. Ice forming ability as warm as -30°C was limited to

  10. Dielectric properties of PMMA/Soot nanocomposites.

    Science.gov (United States)

    Clayton, Lanetra M; Cinke, Martin; Meyyappan, M; Harmon, Julie P

    2007-07-01

    Dielectric analysis (DEA) of relaxation behavior in poly(methyl methacrylate) (PMMA) soot nanocomposites is described herein. The soot, an inexpensive material, consists of carbon nanotubes, amorphous and graphitic carbon and metal particles. Results are compared to earlier studies on PMMA/multi-walled nanotube (MWNT) composites and PMMA/single-walled nanotube (SWNT) composites. The beta relaxation process appeared to be unaffected by the presence of the soot, as was noted earlier in nanotube composites. The gamma relaxation region in PMMA, normally dielectrically inactive, was "awakened" in the PMMA/soot composite. This occurrence is consistent with previously published data on nanotube composites. The dielectric permittivity, s', increased with soot content. The sample with 1% soot exhibited a permittivity (at 100 Hz and 25 degrees C) of 7.3 as compared to 5.1 for neat PMMA. Soot increased the dielectric strength, deltaE, of the composites. The 1% soot sample exhibited a dielectric strength of 6.38, while the neat PMMA had a value of 2.95 at 40 degrees C. The symmetric broadening term (alpha) was slightly higher for the 1% composite at temperatures near the secondary relaxation and near the primary relaxation, but all samples deviated from symmetrical semi-circular behavior (alpha = 1). The impact of the soot filler is seen more clearly in dielectric properties than in mechanical properties studies conducted earlier.

  11. High temperature measuring device

    Science.gov (United States)

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  12. Soot Oxidation in Laminar Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix D

    Science.gov (United States)

    Xu, F.; El-Leathy, A. M.; Faeth, G. M.

    2000-01-01

    Soot oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round jets burning in coflowing air considering acetylene, ethylene, proplyene and propane as fuels. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation mainly occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of stable major gas species (N2, H2O, H2, 02, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by the deconvoluted Li/LiOH atomic absorption technique and flow velocities by laser velocimetry. It was found that soot surface oxidation rates are not particularly affected by fuel type for laminar diffusion flames and are described reasonably well by the OH surface oxidation mechanism with a collision efficiency of 0.10, (standard deviation of 0.07) with no significant effect of fuel type in this behavior; these findings are in good agreement with the classical laminar premixed flame measurements of Neoh et al. Finally, direct rates of surface oxidation by O2 were small compared to OH oxidation for present conditions, based on estimated O2 oxidation rates due to Nagle and Strickland-Constable, because soot oxidation was completed near the flame sheet where O2 concentrations were less than 1.2% by volume.

  13. Soot Oxidation in Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix K

    Science.gov (United States)

    Xu, F.; El-Leathy, A. M.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    Soot oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round jets burning in coflowing air considering acetylene, ethylene, propylene and propane as fuels. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation mainly occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of stable major gas species (N2, H2O, H2, O2, CO, CO2, CH4, C2H2,C2H4, C2H6, C3H6, and C3H8) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by the deconvoluted Li/LiOH atomic absorption technique and flow velocities by laser velocimetry. It was found that soot surface oxidation rates are not particularly affected by fuel type for laminar diffusion flames and are described reasonably well by the OH surface oxidation mechanism with a collision efficiency of 0.10, (standard deviation of 0.07) with no significant effect of fuel type in this behavior; these findings are in good agreement with the classical laminar premixed flame measurements of Neoh et al. Finally, direct rates of surface oxidation by O2 were small compared to OH oxidation for present conditions, based on estimated O2 oxidation rates due to Nagle and Strickland-Constable (1962), because soot oxidation was completed near the flame sheet where O2 concentrations were less than 1.2% by volume.

  14. Temperature measurement and control

    CERN Document Server

    Leigh, JR

    1988-01-01

    This book treats the theory and practice of temperature measurement and control and important related topics such as energy management and air pollution. There are no specific prerequisites for the book although a knowledge of elementary control theory could be useful. The first half of the book is an application oriented survey of temperature measurement techniques and devices. The second half is concerned mainly with temperature control in both simple and complex situations.

  15. Nitrogen dioxide and kerosene-flame soot calibration of photoacoustic instruments for measurement of light absorption by aerosols

    International Nuclear Information System (INIS)

    Arnott, W. Patrick; Moosmu''ller, Hans; Walker, John W.

    2000-01-01

    A nitrogen dioxide calibration method is developed to evaluate the theoretical calibration for a photoacoustic instrument used to measure light absorption by atmospheric aerosols at a laser wavelength of 532.0 nm. This method uses high concentrations of nitrogen dioxide so that both a simple extinction and the photoacoustically obtained absorption measurement may be performed simultaneously. Since Rayleigh scattering is much less than absorption for the gas, the agreement between the extinction and absorption coefficients can be used to evaluate the theoretical calibration, so that the laser gas spectra are not needed. Photoacoustic theory is developed to account for strong absorption of the laser beam power in passage through the resonator. Findings are that the photoacoustic absorption based on heat-balance theory for the instrument compares well with absorption inferred from the extinction measurement, and that both are well within values represented by published spectra of nitrogen dioxide. Photodissociation of nitrogen dioxide limits the calibration method to wavelengths longer than 398 nm. Extinction and absorption at 532 and 1047 nm were measured for kerosene-flame soot to evaluate the calibration method, and the single scattering albedo was found to be 0.31 and 0.20 at these wavelengths, respectively

  16. Temperature measurement device

    International Nuclear Information System (INIS)

    Oltman, B.G.; Eckerman, K.F.; Romberg, G.P.; Prepejchal, W.

    1975-01-01

    Thermoluminescent dosimeter (TLD) material is exposed to a known amount of radiation and then exposed to the environment where temperature measurements are to be taken. After a predetermined time period, the TLD material is read in a known manner to determine the amount of radiation energy remaining in the TLD material. The difference between the energy originally stored by irradiation and that remaining after exposure to the temperature ofthe environment is a measure of the average temperature of the environment during the exposure. (U.S.)

  17. Diffusion air effects on the soot axial distribution concentration in a premixed acetylene/air flame

    Energy Technology Data Exchange (ETDEWEB)

    Fassani, Fabio Luis; Santos, Alex Alisson Bandeira; Goldstein Junior, Leonardo [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia Termica e de Fluidos]. E-mails: fassani@fem.unicamp.br; absantos@fem.unicamp.br; leonardo@fem.unicamp.br; Ferrari, Carlos Alberto [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica. Dept. de Eletronica Quantica]. E-mail: ferrari@ifi.unicamp.br

    2000-07-01

    Soot particles are produced during the high temperature pyrolysis or combustion of hydrocarbons. The emission of soot from a combustor, or from a flame, is determined by the competition between soot formation and its oxidation. Several factors affect these processes, including the type of fuel, the air-to-fuel ratio, flame temperature, pressure, and flow pattern. In this paper, the influence of the induced air diffusion on the soot axial distribution concentration in a premixed acetylene/air flame was studied. The flame was generated in a vertical axis burner in which the fuel - oxidant mixture flow was surrounded by a nitrogen discharge coming from the annular region between the burner tube and an external concentric tube. The nitrogen flow provided a shield that protected the flame from the diffusion of external air, enabling its control. The burner was mounted on a step-motor driven, vertical translation table. The use of several air-to-fuel ratios made possible to establish the sooting characteristics of this flame, by measuring soot concentration along the flame height with a non-intrusive laser light absorption technique. (author)

  18. Strain and temperature measurement

    International Nuclear Information System (INIS)

    Stewart, P.A.E.; Fowler, P.H.

    1988-01-01

    A method of non-invasively measuring strain and temperature of an object, substantially simultaneously, using neutrons of selected energy levels is described. A pulsed neutron source is made to emit thermal and epithermal neutrons in a collimated beam directed at the object. Temperature is monitored by observing the thermal Doppler broadening of resonances in the neutron transmission characteristic for the epithermal neutrons and strain is measured from observations made of changes to the thermal neutron diffraction pattern. The object may be a gas turbine blade or a thrust bearing. (author)

  19. Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures

    KAUST Repository

    Rakha, Ihsan Allah

    2015-05-01

    The steady coflow diffusion flame is a widely used configuration for studying combustion kinetics, flame dynamics, and pollutant formation. In the current work, a set of diluted ethylene-air coflow flames are simulated to study the formation, growth, and oxidation of soot, with a focus on the effects of pressure on soot yield. Firstly, we assess the ability of a high performance CFD solver, coupled with detailed transport and kinetic models, to reproduce experimental measurements, like the temperature field, the species’ concentrations and the soot volume fraction. Fully coupled conservation equations for mass, momentum, energy, and species mass fractions are solved using a low Mach number formulation. Detailed finite rate chemistry describing the formation of Polycyclic Aromatic Hydrocarbons up to cyclopenta[cd]pyrene is used. Soot is modeled using a moment method and the resulting moment transport equations are solved with a Lagrangian numerical scheme. Numerical and experimental results are compared for various pressures. Reasonable agreement is observed for the flame height, temperature, and the concentrations of various species. In each case, the peak soot volume fraction is predicted along the centerline as observed in the experiments. The predicted integrated soot mass at pressures ranging from 4-8 atm, scales as P2.1, in satisfactory agreement with the measured integrated soot pressure scaling (P2.27). Significant differences in the mole fractions of benzene and PAHs, and the predicted soot volume fractions are found, using two well-validated chemical kinetic mechanisms. At 4 atm, one mechanism over-predicts the peak soot volume fraction by a factor of 5, while the other under-predicts it by a factor of 5. A detailed analysis shows that the fuel tube wall temperature has an effect on flame stabilization.

  20. Soot oxidation over NOx storage catalysts. Activity and deactivation

    International Nuclear Information System (INIS)

    Krishna, K.; Makkee, M.

    2006-01-01

    Soot oxidation activity and deactivation of NO x storage and reduction (NSR) catalysts containing Pt, K, and Ba supported on Al 2 O 3 , are studied under a variety of reaction conditions. K-containing catalysts decrease soot oxidation temperature with O 2 alone and the presence of Pt further enhance the activity due to synergetic effect. The active species responsible for synergism on Pt/K-Al 2 O 3 are unstable and cannot be regenerated. Soot oxidation temperature decreases by about 150 o C with NO+O 2 exhaust feed gas and under lean conditions NSR system acts as catalysed soot filter (CSF). The reactions that are mainly responsible for decreasing soot oxidation temperature are: (1) soot oxidation with NO 2 followed by NO recycles to NO 2 , and (2) soot oxidation with O 2 assisted by NO 2 . Only a part of the stored NO x that is decomposed at high temperatures under lean conditions is found to be useful for soot oxidation. NO x storage capacity of NSR catalysts decreases upon ageing under soot oxidising conditions. This will lead to a decreased soot oxidation activity on stored nitrate decomposition. Pt/K-Al 2 O 3 catalyst is more active, but least stable compared with Pt/Ba-Al 2 O 3 . (author)

  1. Temperature measurements by thermocouples

    International Nuclear Information System (INIS)

    Liermann, J.

    1975-01-01

    The measurement of a temperature (whatever the type of transducer used) raises three problems: the choice of transducer; where it should be placed; how it should be fixed and protected. These are the three main points examined, after a brief description of the most commonly used thermocouples [fr

  2. Thermal fragmentation and deactivation of combustion-generated soot particles

    KAUST Repository

    Raj, Abhijeet

    2014-09-01

    The effect of thermal treatment on diesel soot and on a commercial soot in an inert environment under isothermal conditions at intermediate temperatures (400-900°C) is studied. Two important phenomena are observed in both the soot samples: soot fragmentation leading to its mass loss, and loss of soot reactivity towards O2. Several experimental techniques such as high resolution transmission electron microscopy, electron energy loss spectroscopy, thermo-gravimetric analysis with mass spectrometry, elemental analysis, Fourier transform infrared spectroscopy and X-ray diffraction have been used to identify the changes in structures, functional groups such as oxygenates and aliphatics, σ and π bonding, O/C and H/C ratios, and crystallite parameters of soot particles, introduced by heat. A decrease in the size of primary particles and an increase in the average polycyclic aromatic hydrocarbon (PAH) size was observed in soots after thermal treatment. The activation energies of soot oxidation for thermally treated soot samples were found to be higher than those for the untreated ones at most conversion levels. The cyclic or acyclic aliphatics with sp3 hybridization were present in significant amounts in all the soot samples, but their concentration decreased with thermal treatment. Interestingly, the H/C and the O/C ratios of soot particles increased after thermal treatment, and thus, they do not support the decrease in soot reactivity. The increase in the concentration of oxygenates on soot surface indicate that their desorption from soot surface in the form of CO, CO2 and other oxygenated compounds may not be significant at the temperatures (400-900°C) studied in this work. © 2014 The Combustion Institute.

  3. Electrometric Aviation Soot Monitor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a sensitive PM measurement instrument to determine soot particle mass distribution from aircraft engine exhausts as well as from other IC...

  4. Non-thermal soot denuder, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a non-thermal soot denuder for measuring chemical components of the nucleation mode particulate matter emissions from gas turbine engines, in...

  5. Monte carlo simulation for soot dynamics

    KAUST Repository

    Zhou, Kun

    2012-01-01

    A new Monte Carlo method termed Comb-like frame Monte Carlo is developed to simulate the soot dynamics. Detailed stochastic error analysis is provided. Comb-like frame Monte Carlo is coupled with the gas phase solver Chemkin II to simulate soot formation in a 1-D premixed burner stabilized flame. The simulated soot number density, volume fraction, and particle size distribution all agree well with the measurement available in literature. The origin of the bimodal distribution of particle size distribution is revealed with quantitative proof.

  6. Method for removing soot from exhaust gases

    Science.gov (United States)

    Suib, Steven L.; Dharmarathna, D. A. Saminda; Pahalagedara, Lakshitha R.

    2018-01-16

    A method for oxidizing soot from diesel exhaust gas from a diesel engine. The method involves providing a diesel particulate filter for receiving the diesel exhaust gas; coating a catalyst composition on the diesel particulate filter; and contacting the soot from the diesel exhaust gas with the catalyst coated diesel particulate filter at a temperature sufficient to oxidize the soot to carbon dioxide. The catalyst composition is a doped or undoped manganese oxide octahedral molecular sieve (OMS-2) material. A diesel exhaust gas treatment system that includes a diesel particulate filter for receiving diesel exhaust gas from a diesel engine and collecting soot; and a catalyst composition coated on the diesel particulate filter. The catalyst composition is a doped or undoped manganese oxide octahedral molecular sieve (OMS-2).

  7. Development of a novel heterogeneous flow reactor -- Soot formation and nanoparticle catalysis

    Science.gov (United States)

    Camacho, Joaquin

    The development of novel experimental approaches to investigate fundamental surface kinetics is presented. Specifically, fundamental soot formation and surface catalysis processes are examined in isolation from other competing processes. In terms of soot formation, two experimental techniques are presented: the Burner Stabilized Stagnation (BSS) flame configuration is extended to isolate the effect of the parent fuel structure on soot formation and the fundamental rate of surface oxidation for nascent soot is measured in a novel aerosol flow reactor. In terms of nanoparticles, the physical and chemical properties of freely suspended nanoparticles are investigated in a novel aerosol flow reactor for methane oxidation catalyzed by palladium. The role of parent fuel structure within soot formation is examined by following the time resolved formation nascent soot from the onset of nucleation to later growth stages for premixed BSS flames. Specifically, the evolution of the detailed particle size distribution function (PSDF) is compared for butanol, butane and C6 hydrocarbons in two separate studies where the C/O ratio and temperature are fixed. Under this constraint, the overall sooting process were comparable as evidenced by similar time resolved bimodal PSDF. However, the nucleation time and the persistence of nucleation with time is strongly dependent upon the structure of the parent fuel. For the C6 hydrocarbon fuels, the fastest onset of soot nucleation is observed in cyclohexane and benzene flames and this may be due to significant aromatic formation that is predicted in the pre-flame region. In addition, the evolution of the PSDF shows that nucleation ends sooner in cylclohexane and benzene flames and this may be due to relatively quick depletion of soot precursors such as acetylene and benzene. Interestingly,within the butanol fuels studied the effect of the branched chain in i-butanol and i-butane was more significant than the presence of fuel bound oxygen. A

  8. Light changes the atmospheric reactivity of soot

    Science.gov (United States)

    D'Anna, Barbara; Monge, Maria-Eugenia; George, Christian; Ammann, Markus; Donaldson, D. Jamie

    2010-05-01

    Soot particles formed by incomplete combustion processes comprise a significant portion of the fine aerosol loading (below 1micron). These particles affect the radiative forcing contributing to global warming and have increased toxicity relative to larger particles because they may settle and persist in the deeper respiratory tract, and can even cross biological barriers. In addition, they are often coated with polycyclic aromatic hydrocarbons (PAHs). Soot particles exhibit a large specific surface area, approx. 100 m2 g-1, which suggests a potential for heterogeneous interactions with atmospheric trace gases. Consequently, soot was suggested to be an important sink for some atmospheric oxidants such as O3 or NOx and its heterogeneous chemistry has been largely investigated in the past years. However, its atmospheric impact was suggested to be negligible due to a rapid soot surface deactivation under atmospheric conditions. As previous studies were done under dark conditions, we decided to investigate the effect of light on the heterogeneous reaction of NO2 on various soot samples. As well, we studied the effect of O3 and light exposure on the aging of soot samples. The heterogeneous reaction between soot particles and NO2 was studied by means of a coated flow tube equipped with near-UV emitting lamps (300-420 nm). The effect of O3 and light on the wettability of soot was studied by contact angle measurements. The characterization of the soot particles was performed by TEM, ESEM and AMS. Different combustion conditions were used to produce the soot samples, which were generated with a mini-CAST soot generator using propane as fuel. We determined the uptake coefficients for different gas phase NO2 concentrations (15-120 ppbv) under near UV irradiation. The results showed that the heterogeneous reaction of NO2 and soot under irradiation leads to NO and HONO production with different yields according to the combustion conditions of the generated soot particles. The

  9. Quantitative effects of rapid heating on soot-particle sizing through analysis of two-pulse LII

    KAUST Repository

    Cenker, Emre

    2017-02-27

    During the rapid laser pulse heating and consecutive cooling in laser-induced incandescence (LII), soot particles may undergo thermal annealing and sublimation processes which lead to a permanent change in its optical properties and its primary particle size, respectively. Overall, effects of these two processes on soot and LII model-based particle sizing are investigated by measuring the two-color time-resolved (2C-TiRe) LII signal decay from in-flame soot after two consecutive laser pulses at 1064-nm wavelength. Experiments are carried out on a non-premixed laminar ethylene/air flame from a Santoro burner with both low and moderate laser fluences suitable for particle sizing. The probe volume is set to a radial position close to the flame axis where the soot particles are known to be immature or less graphitic. With the first pulse, soot is pre-heated, and the LII signal after the consecutive second pulse is used for analysis. The two-color incandescence emission technique is used for the pyrometric determination of the LII-heated peak soot temperature at the second pulse. A new LII simulation tool is developed which accounts for particle heating via absorption and annealing, and cooling via sublimation, conduction, and radiation with various existing sub-models from the literature. The same approach of using two laser pulses is implemented in the simulations. Measurements indicate that thermal annealing and associated absorption enhancement becomes important at laser fluences above 0.17 J/cm2 for the immature in-flame soot. After a heating pulse at 0.33 J/cm2, the increase of the soot absorption function is calculated as 35% using the temperature measured at the second pulse and an absorption model based on the Rayleigh approximation. Present annealing model, on the other hand, predicts graphitization of soot even in the absence of laser heating at typical flame temperatures. Recorded experimental LII signal decays and LII-heated peak soot temperature

  10. Experimental study on burning behaviors of liquid fuels with different sooting levels at high altitude

    Directory of Open Access Journals (Sweden)

    Liu Jiahao

    2017-01-01

    Full Text Available To validate the feasibility of classical fire scaling laws under low pressure, three typical liquid fuels with different sooting levels, i. e. ethanol, n-heptane and jet-A, were employed in this paper to perform a sequence of pool fires in a high altitude city, Lhasa, Tibet, China (3650 m, 64.3 kPa. Mass loss, axial temperature profile and radiative heat flux were recorded in each test. From the assessment of experimental data, it can be concluded that the dimensionless burning intensity m”μ /D can be correlated against the Grashof number to different powers for all the three fuels, and the exponent increases with the sooting level of fuels. A correlated relationship expressed as ΔT ~ [z(P/Q2/5 ]η can be applied to analyze the axial temperature rises, partitioning flame region, intermittent region and plume region with the modified demarcations, i. e. 0.42 and 1.06. In addition, the averaged flame temperature grows higher with declining sooting level of fuels, while the radiative heat fluxes exhibit the opposite results. Moreover, the measured radiative heat fluxes for different fuels are proportional to 5 m f L T , and the soot volume fraction apparently increases with the sooting level of the fuels under low pressure condition.

  11. Aromatics Oxidation and Soot Formation in Flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. B.; Richter, H.

    2005-03-29

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

  12. Sooting Characteristics and Modeling in Counterflow Diffusion Flames

    KAUST Repository

    Wang, Yu

    2013-11-01

    temperature index (STI) and a sooting sensitivity index (SSI) were proposed to present the sooting tendencies of different fuels and their sensitivities to strain rates.

  13. Neutron ion temperature measurement

    International Nuclear Information System (INIS)

    Strachan, J.D.; Hendel, H.W.; Lovberg, J.; Nieschmidt, E.B.

    1986-11-01

    One important use of fusion product diagnostics is in the determination of the deuterium ion temperature from the magnitude of the 2.5 MeV d(d,n) 3 He neutron emission. The detectors, calibration methods, and limitations of this technique are reviewed here with emphasis on procedures used at PPPL. In most tokamaks, the ion temperature deduced from neutrons is in reasonable agreement with the ion temperature deduced by other techniques

  14. Ignition delay and soot oxidative reactivity of MTBE blended diesel fuel

    KAUST Repository

    Yang, Seung Yeon

    2014-04-01

    Methyl tert-butyl ether (MTBE) was added to diesel fuel to investigate the effect on ignition delay and soot oxidative reactivity. An ignition quality tester (IQT) was used to study the ignition propensity of MTBE blended diesel fuels in a reactive spray environment. The IQT data showed that ignition delay increases linearly as the MTBE fraction increases in the fuel. A four-stroke single cylinder diesel engine was used to generate soot samples for a soot oxidation study. Soot samples were pre-treated using a tube furnace in a nitrogen environment to remove any soluble organic fractions and moisture content. Non-isothermal oxidation of soot samples was conducted using a thermogravimetric analyzer (TGA). It was observed that oxidation of \\'MTBE soot\\' started began at a lower temperature and had higher reaction rate than \\'diesel soot\\' across a range of temperatures. Several kinetic analyses including an isoconversional method and a combined model fitting method were carried out to evaluate kinetic parameters. The results showed that Diesel and MTBE soot samples had similar activation energy but the pre-exponential factor of MTBE soot was much higher than that of the Diesel soot. This may explain why MTBE soot was more reactive than Diesel soot. It is suggested that adding MTBE to diesel fuel is better for DPF regeneration since an MTBE blend can significantly influence the ignition characteristics and, consequently, the oxidative reactivity of soot. Copyright © 2014 SAE International.

  15. Laser spectroscopic measurement of the effects of the mixing process on NO and soot concentrations in diesel engines; Laserspektroskopische Methoden zur Untersuchung des Einflusses der Gemischbildung auf NO- und Russkonzentration im Dieselmotor

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, L.; Keller, F.; Koenig, G.; Wagner, E. [DaimlerChrysler AG, Stuttgart (Germany). Forschung und Technologie 1; Bessler, W.; Hildenbrand, F.; Schorr, J.; Schulz, C.; Wolfrum, J. [Heidelberg Univ. (Germany). Physikalisch-Chemisches Inst.; Boltz, J.; Brueggemann, D. [Stuttgart Univ. (Germany). Inst. fuer Thermodynamik der Luft- und Raumfahrt

    2000-07-01

    Optimised mixture formation in DI-diesel engines is important for drive concepts with very low consumption and emissions. Their optimisation can be accelerated very much by viewing the processes in the combustion chamber using optical and laser diagnostics. Therefore research engines have been developed with access for 2-D-laser diagnostics and very low disturbance of combustion and pollutant formation. Diagnostic methods for mixture formation, soot and NO have been adapted and verified at the conditions in Diesel engines. The LII (laser-Induced-Incandescence) technique was adapted to the optical engine and applied for measuring in-cylinder soot concentration. Using calibration measurements at a laminar burner the soot concentration can be quantified in engine measurements. A first series of measurements in the engine was used to clarify the conditions where the technique can be applied. The soot burnout during the late phase of combustion can be well analyzed. However, during the main combustion period the soot concentration is so high that due to background soot radiation and absorption of laser and LII-signal soot can only be measured in surface zones. The effect of EGR and injection rail pressure on soot formation and oxidation in the transparent HD-Diesel engine is shown. A LIF (Laser-Induced-Fluorescence) technique was developed and successfully applied to investigate NO-distribution during the Diesel combustion process. A KrF-laser is used for NO excitation. Interference due to other molecules could be minimized using results of a detailed spectroscopic investigation. Furthermore a method, using the spectral structure of O2-LIF, was developed to determine and quantify signal absorption in burned gases. A combination of LIF and Mie-imaging using highly efficient non-volatile fluorescence tracers was used to investigate drop-size distributions in Diesel sprays in a high-pressure cell. Spectroscopic background was gained by additional experiments in

  16. A survey of temperature measurement

    International Nuclear Information System (INIS)

    Saltvold, J.R.

    1976-03-01

    Many different techniques for measuring temperature have been surveyed and are discussed. The concept of temperature and the physical phenomena used in temperature measurement are also discussed. Extensive tables are presented in which the range and accuracy of the various techniques and other related data are included. (author)

  17. Fractal-like dimension of nanometer Diesel soot particles

    Energy Technology Data Exchange (ETDEWEB)

    Skillas, G.; Baltensperger, U. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Siegmann, K. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-11-01

    Measurements with a low-pressure impactor and a differential mobility analyser were conducted for Diesel soot at various engine loads. By means of these measurements a fractal-like dimension of Diesel soot particles, with diameters ranging from 55 up to 260 nm, was established. (author) 2 figs., 7 refs.

  18. Soot and Spectral Radiation Modeling for a High-Pressure Turbulent Spray Flame

    Energy Technology Data Exchange (ETDEWEB)

    Ferreryo-Fernandez, Sebastian [Pennsylvania State Univ., University Park, PA (United States); Paul, Chandan [Pennsylvania State Univ., University Park, PA (United States); Sircar, Arpan [Pennsylvania State Univ., University Park, PA (United States); Imren, Abdurrahman [Pennsylvania State Univ., University Park, PA (United States); Haworth, Daniel C [Pennsylvania State Univ., University Park, PA (United States); Roy, Somesh P [Marquette University (United States); Modest, Michael F [University of California Merced (United States)

    2017-04-26

    Simulations are performed of a transient high-pressure turbulent n-dodecane spray flame under engine-relevant conditions. An unsteady RANS formulation is used, with detailed chemistry, a semi-empirical two-equation soot model, and a particle-based transported composition probability density function (PDF) method to account for unresolved turbulent fluctuations in composition and temperature. Results from the PDF model are compared with those from a locally well-stirred reactor (WSR) model to quantify the effects of turbulence-chemistry-soot interactions. Computed liquid and vapor penetration versus time, ignition delay, and flame lift-off height are in good agreement with experiment, and relatively small differences are seen between the WSR and PDF models for these global quantities. Computed soot levels and spatial soot distributions from the WSR and PDF models show large differences, with PDF results being in better agreement with experimental measurements. An uncoupled photon Monte Carlo method with line-by-line spectral resolution is used to compute the spectral intensity distribution of the radiation leaving the flame. This provides new insight into the relative importance of molecular gas radiation versus soot radiation, and the importance of turbulent fluctuations on radiative heat transfer.

  19. Light Absorption By Coated Soot

    Science.gov (United States)

    Sedlacek, A. J.; Lee, J.; Onasch, T. B.; Davidovits, P.; Cross, E. S.

    2009-12-01

    The contribution of aerosol absorption on direct radiative forcing is still an active area of research, in part, because aerosol extinction is dominated by light scattering and, in part, because the primary absorbing aerosol of interest, soot, exhibits complex aging behavior that alters its optical properties. The consequences of this can be evidenced by the work of Ramanathan and Carmichael (2008) who suggest that incorporating the atmospheric heating due to brown clouds will increase black carbon (BC) radiative forcing from the IPCC best estimate of 0.34 Wm-2 (±0.25 Wm-2) (IPCC 2007) to 0.9 Wm-2. This noteworthy degree of the uncertainty is due largely to the interdependence of BC optical properties on particle mixing state and aggregate morphology, each of which changes as the particle ages in the atmosphere and becomes encapsulated within a coating of inorganic and/or organic substances. With the advent of techniques that can directly measure aerosol light absorption without influences due to collection substrate or light scattering (e.g., photoacoustic spectroscopy (Arnott et al., 2005; Lack et al., 2006) and photothermal interferometry (Sedlacek and Lee 2007)) the potential exists for quantifying this interdependence. In July 2008, a laboratory-based measurement campaign, led by Boston College and Aerodyne, was initiated to begin addressing this interdependence. To achieve this objective measurements of both the optical and physical properties of flame-generated soot under nascent, coated and denuded conditions were conducted. In this paper, light absorption by dioctyl sebacate (DOS) encapsulated soot and sulfuric acid coated soot using the technique of photothermal interferometry will be presented. In the case of DOS-coated soot, a monotonic increase in light absorption as a function DOS coating thickness to nearly 100% is observed. This observation is consistent with a coating-induced amplification in particle light absorption. (Bond et al. 2006) However

  20. Experimental verification of the dominant influence of extended carbon networks on the structural, electrical and magnetic properties of a common soot

    Science.gov (United States)

    Dunne, L. J.; Nolan, P. F.; Munn, J.; Terrones, M.; Jones, T.; Kathirgamanathan, P.; Fernandez, J.; Hudson, A. D.

    1997-12-01

    Common soots are disordered carbonaceous materials containing several per cent of heteroatoms. A question of some importance is to what extent pure carbon networks dominate the properties of common soots. Here, we report the results of a comparative study of fullerene soots which are a form of pure partially ordered carbon and those formed from flaming polystyrene combustion which contain a few per cent of oxygen atoms, using electron diffraction, electron spin resonance (ESR), infra-red transmission and measurements of electrical conductivity. It has been found that despite some important characteristic differences, the annealed fullerene soot and flaming polystyrene soot have a number of important structural, electrical and magnetic features in common, provided that the flame and annealing temperatures are the same. This suggests that the graphitic layer and fullerene related tubular structures found in these materials dominate the electrical properties of these soots regardless of the presence of small quantities of heteroatoms in the soot derived from the flaming combustion of polystyrene.

  1. The many faces of soot: characterization of soot nanoparticles produced by engines.

    Science.gov (United States)

    Niessner, Reinhard

    2014-11-10

    Soot nanoparticles produced by engines constitute a threat to human health. For the analytical chemist, soot is a hard nut to crack as the released particles undergo rapid changes in their size, shape, and number concentration. The complete characterization of soot will be essential to meet future low-emission standards. Besides measuring the light extinction, modern analytical chemistry can determine a variety of less-known effects, such as condensation properties, immune response in vertebrates, and impact on the cardiovascular function of a beating heart. Photon emission and in particular Raman spectroscopy provides information on the nanocrystallinity, while thermoelectron emission allows the number of electrical particles to be counted. Even the "simple" combustion of soot nanoparticles offers potential for the characterization of the particles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Modeling polychlorinated biphenyl sorption isotherms for soot and coal

    NARCIS (Netherlands)

    Jantunen, A.P.K.; Koelmans, A.A.; Jonker, M.T.O.

    2010-01-01

    Sorption isotherms (pg-ng/L) were measured for 11 polychlorinated biphenyls (PCBs) of varying molecular planarity from aqueous solution to two carbonaceous geosorbents, anthracite coal and traffic soot. All isotherms were reasonably log-log-linear, but smooth for traffic soot and staircase-shaped

  3. Visualizing the mobility of silver during catalytic soot oxidation

    DEFF Research Database (Denmark)

    Gardini, Diego; Christensen, Jakob M.; Damsgaard, Christian Danvad

    2016-01-01

    The catalytic activity and mobility of silver nanoparticles used as catalysts in temperature programmed oxidation of soot:silver (1:5 wt:wt) mixtures have been investigated by means of flow reactor experiments and in situ environmental transmission electron microscopy (ETEM). The carbon oxidation...... temperature was significantly lower compared to uncatalyzed soot oxidation with soot and silver loosely stirred together (loose contact) and lowered further with the two components crushed together (tight contact). The in situ TEM investigations revealed that the silver particles exhibited significant...

  4. Radiometric temperature measurements fundamentals

    CERN Document Server

    Zhang, Zhuomin M; Machin, Graham

    2009-01-01

    This book describes the theory of radiation thermometry, both at a primary level and for a variety of applications, such as in the materials processing industries and remote sensing. This book is written for those who will apply radiation thermometry in industrial practice; use radiation thermometers for scientific research; the radiation thermometry specialist in a national measurement institute; developers of radiation thermometers who are working to innovate products for instrument manufacturers, and developers of non-contact thermometry methods to address challenging thermometry problems.

  5. Temperature measurement in the sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnamacharyulu, R.J.; Rao, L.V.G.

    ), their advantages and limitations are also touched upon. Calibration of various instruments used for temperature measurement in the sea and the special setup/facilities needed for this purpose are also discussed...

  6. Effects of dicarboxylic acid coating on the optical properties of soot.

    Science.gov (United States)

    Xue, Huaxin; Khalizov, Alexei F; Wang, Lin; Zheng, Jun; Zhang, Renyi

    2009-09-28

    Soot is a major component of atmospheric aerosols responsible for absorption of visible solar radiation. Internal mixing of soot with transparent materials can enhance its ability to absorb and scatter light, resulting in a larger role of soot in climate forcing. We have investigated the absorption and scattering of visible light (532 nm) by soot aerosol internally mixed with succinic and glutaric acids using a combination of a cavity ring-down spectrometer and an integrating nephelometer. The measurements were performed for flame-generated soot aerosol with well-characterized morphology and mixing state in the particle size range from 155 to 320 nm. Thin coatings of dicarboxylic acids on soot aggregates (with a mass fraction of 0.1-0.4) enhance significantly light scattering (up to 3.8 fold) and slightly light absorption (less than 1.2 fold). Cycling the coated soot aerosol through high relative humidity (humidified to 90% RH and then dried to 5% RH) promotes further increase in light absorption and scattering for soot internally mixed with glutaric acid, but not for soot mixed with succinic acid. The larger effect of glutaric acid on light absorption and scattering is caused by the irreversible restructuring of soot aggregates induced by the coating material. Our results indicate that the enhancement in the optical properties of soot by transparent coatings is strongly related to the ability of the coating materials to change the morphology of soot aggregates.

  7. LES of Sooting Flames

    Science.gov (United States)

    2006-12-01

    investigated the formation of carbon in a well-stirred reactor. The critical C/O ratio for soot inception was observed and compared to Bunsen -Type flames ...The computations reproduced the flame structure, with reasonable agreement of the velocity field. They designed the swirl burner to match the...the vortex breakdown. 121 [203] introduced the compositional structure and flow field of two flames on the same burner . The two flames have the same

  8. Assessing Single Particle Soot Photometer and Integrating Sphere/Integrating Sandwich Spectrophotometer measurement techniques for quantifying black carbon concentration in snow

    Directory of Open Access Journals (Sweden)

    J. P. Schwarz

    2012-11-01

    Full Text Available We evaluate the performance of the Single Particle Soot Photometer (SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW in quantifying the concentration of refractory black carbon (BC in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60% than for atmospheric sampling (<30%. Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow can exist in larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the ISSW revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow or ice formed from fallen snow using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

  9. Catalytic combustion of diesel soot on Co,K/MgO catalysts. Effect of the potassium loading on activity and stability

    Energy Technology Data Exchange (ETDEWEB)

    Querini, C.A.; Cornaglia, L.M.; Ulla, M.A.; Miro, E.E. [Instituto de Investigaciones en Catalisis y Petroquimica - INCAPE, FIQ, UNL-CONICET, Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    1999-03-08

    Co,K/MgO catalysts with 12wt% of Co and 1.5, 4.5 and 7.5wt% of K, calcined at 400C are active for the combustion of diesel soot. Among them, the one containing 4.5wt% of K is that which burns soot at the lowest temperature (378C). Coincidentally, this is the catalyst presenting the highest K/Mg and K/O surface ratios in XPS measurements. When the calcination temperature is increased at 500C, both the solid containing 4.5% of K and the one containing 1.5% as well as the unpromoted catalyst (Co/MgO) noticeably lose activity due to the formation of a solid solution (Co, Mg). However, the solid with the highest K content (7.5wt%) presents a similar activity at different calcination temperatures (400C, 500C and 700C). It has been found that the activity of these solids is directly related to the reducibility of cobalt, thus indicating that the reaction is carried out by a redox mechanism. Potassium plays different roles in these catalysts: (1) it increases the catalyst-soot contact by increasing surface mobility, (2) it preserves the reducibility and dispersion of cobalt by improving stability against thermal treatments, and (3) it favors the oxidation of soot by consuming the carbon to form carbonate species during soot combustion. It was also found that soot with a higher content of sulfur (1050ppm) is more efficiently burned than that containing low amounts of sulfur (70ppm). However, the severe sulfation of the catalyst leads to a noticeable loss of activity. In experiments of carbon monoxide oxidation, it was found that conversion is practically total between 400C and 500C under the conditions used in this work. The direct impregnation of the soot with either Co or Co and K, showed lower combustion temperatures if compared with the mechanical mixtures of soot and Co/MgO or Co,K/MgO, suggesting that the soot-catalyst contact poses a physical limitation on the oxidation activity. This important result suggests that the soot-catalyst contacting problem is the main

  10. Michelson interferometer for measuring temperature

    OpenAIRE

    Xie, Dong; Xu, Chunling; wang, Anmin

    2016-01-01

    We investigate that temperature can be measured by a modified Michelson interferometer, where at least one reflected mirror is replaced by a thermalized sample. Both of two mirrors replaced by the corresponding two thermalized samples can help to approximatively improve the resolution of temperature up to twice than only one mirror replaced by a thermalized sample. For further improving the precision, a nonlinear medium can be employed. The Michelson interferometer is embedded in a gas displa...

  11. Michelson interferometer for measuring temperature

    Science.gov (United States)

    Xie, Dong; Xu, Chunling; Wang, An Min

    2017-09-01

    We investigate that temperature can be measured by a modified Michelson interferometer, where at least one reflected mirror is replaced by a thermalized sample. Both of two mirrors replaced by the corresponding two thermalized samples can help to approximatively improve the resolution of temperature up to twice than only one mirror replaced by a thermalized sample. For further improving the precision, a nonlinear medium can be employed. The Michelson interferometer is embedded in a gas displaying Kerr nonlinearity. We obtain the analytical equations and numerically calculate the precision with parameters within the reach of current technology, proving that the precision of temperature can be greatly enhanced by using a nonlinear medium. Our results show that one can create an accurate thermometer by measuring the photons in the Michelson interferometer, with no need to directly measure the population of thermalized sample.

  12. Ultrasensitive, Fast-Response Size-Dependent Soot Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a "black carbon" (soot) monitor for measuring non-volatile particulate emissions from gas turbine engines employing a proprietary optical...

  13. Quantum interferometric measurements of temperature

    Science.gov (United States)

    Jarzyna, Marcin; Zwierz, Marcin

    2015-09-01

    We provide a detailed description of the quantum interferometric thermometer, which is a device that estimates the temperature of a sample from the measurements of the optical phase. We rigorously analyze the operation of such a device by studying the interaction of the optical probe system prepared in a single-mode Gaussian state with a heated sample modeled as a dissipative thermal reservoir. We find that this approach to thermometry is capable of measuring the temperature of a sample in the nanokelvin regime. Furthermore, we compare the fundamental precision of quantum interferometric thermometers with the theoretical precision offered by the classical idealized pyrometers, which infer the temperature from a measurement of the total thermal radiation emitted by the sample. We find that the interferometric thermometer provides a superior performance in temperature sensing even when compared with this idealized pyrometer. We predict that interferometric thermometers will prove useful for ultraprecise temperature sensing and stabilization of quantum optical experiments based on the nonlinear crystals and atomic vapors.

  14. Catalytic oxidation of soot over alkaline niobates

    International Nuclear Information System (INIS)

    Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.

    2013-01-01

    Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

  15. A small porous-plug burner for studies of combustion chemistry and soot formation

    Science.gov (United States)

    Campbell, M. F.; Schrader, P. E.; Catalano, A. L.; Johansson, K. O.; Bohlin, G. A.; Richards-Henderson, N. K.; Kliewer, C. J.; Michelsen, H. A.

    2017-12-01

    We have developed and built a small porous-plug burner based on the original McKenna burner design. The new burner generates a laminar premixed flat flame for use in studies of combustion chemistry and soot formation. The size is particularly relevant for space-constrained, synchrotron-based X-ray diagnostics. In this paper, we present details of the design, construction, operation, and supporting infrastructure for this burner, including engineering attributes that enable its small size. We also present data for charactering the flames produced by this burner. These data include temperature profiles for three premixed sooting ethylene/air flames (equivalence ratios of 1.5, 1.8, and 2.1); temperatures were recorded using direct one-dimensional coherent Raman imaging. We include calculated temperature profiles, and, for one of these ethylene/air flames, we show the carbon and hydrogen content of heavy hydrocarbon species measured using an aerosol mass spectrometer coupled with vacuum ultraviolet photoionization (VUV-AMS) and soot-volume-fraction measurements obtained using laser-induced incandescence. In addition, we provide calculated mole-fraction profiles of selected gas-phase species and characteristic profiles for seven mass peaks from AMS measurements. Using these experimental and calculated results, we discuss the differences between standard McKenna burners and the new miniature porous-plug burner introduced here.

  16. Soot Reactivity in Conventional Combustion and Oxy-fuel Combustion Environments

    DEFF Research Database (Denmark)

    Abián, María; Jensen, Anker D.; Glarborg, Peter

    2012-01-01

    A study of the reactivity of soot produced from ethylene pyrolysis at different temperatures and CO2 atmospheres toward O2 and CO2 has been carried out using a thermogravimetric analyzer. The purpose was to quantify how soot reactivity is affected by the gas environment and temperature history of...

  17. Microwave-assisted in-situ regeneration of a perovskite coated diesel soot filter

    NARCIS (Netherlands)

    Zhang-Steenwinkel, Y.; van der Zande, L.M.; Castricum, H.L.; Bliek, A.; van den Brink, R.W.; Elzinga, G.D.

    2005-01-01

    Dielectric heating may be used as an in situ technique for the periodic regeneration of soot filters, as those used in Diesel engines. As generally the Diesel exhaust temperatures are below the soot light-off temperature, passive regeneration is not possible. Presently, we have investigated the

  18. Soot modeling of counterflow diffusion flames of ethylene-based binary mixture fuels

    KAUST Repository

    Wang, Yu

    2015-03-01

    A soot model was developed based on the recently proposed PAH growth mechanism for C1-C4 gaseous fuels (KAUST PAH Mechanism 2, KM2) that included molecular growth up to coronene (A7) to simulate soot formation in counterflow diffusion flames of ethylene and its binary mixtures with methane, ethane and propane based on the method of moments. The soot model has 36 soot nucleation reactions from 8 PAH molecules including pyrene and larger PAHs. Soot surface growth reactions were based on a modified hydrogen-abstraction-acetylene-addition (HACA) mechanism in which CH3, C3H3 and C2H radicals were included in the hydrogen abstraction reactions in addition to H atoms. PAH condensation on soot particles was also considered. The experimentally measured profiles of soot volume fraction, number density, and particle size were well captured by the model for the baseline case of ethylene along with the cases involving mixtures of fuels. The simulation results, which were in qualitative agreement with the experimental data in the effects of binary fuel mixing on the sooting structures of the measured flames, showed in particular that 5% addition of propane (ethane) led to an increase in the soot volume fraction of the ethylene flame by 32% (6%), despite the fact that propane and ethane are less sooting fuels than is ethylene, which is in reasonable agreement with experiments of 37% (14%). The model revealed that with 5% addition of methane, there was an increase of 6% in the soot volume fraction. The average soot particle sizes were only minimally influenced while the soot number densities were increased by the fuel mixing. Further analysis of the numerical data indicated that the chemical cross-linking effect between ethylene and the dopant fuels resulted in an increase in PAH formation, which led to higher soot nucleation rates and therefore higher soot number densities. On the other hand, the rates of soot surface growth per unit surface area through the HACA mechanism were

  19. Black carbon aerosol properties measured by a single particle soot photometer in emissions from biomass burning in the laboratory and field

    Science.gov (United States)

    G. R. McMeeking; J. W. Taylor; A. P. Sullivan; M. J. Flynn; S. K. Akagi; C. M. Carrico; J. L. Collett; E. Fortner; T. B. Onasch; S. M. Kreidenweis; R. J. Yokelson; C. Hennigan; A. L. Robinson; H. Coe

    2010-01-01

    We present SP2 observations of BC mass, size distributions and mixing state in emissions from laboratory and field biomass fires in California, USA. Biomass burning is the primary global black carbon (BC) source, but understanding of the amount emitted and its physical properties at and following emission are limited. The single particle soot photometer (SP2) uses a...

  20. Investigations of Sooting Laminar Coflow Diffusion Flames at Elevated Pressures

    KAUST Repository

    Steinmetz, Scott A.

    2016-12-01

    Soot is a common byproduct of hydrocarbon based combustion systems. It poses a risk to human and environmental health, and can negatively or positively affect combustor performance. As a result, there is significant interest in understanding soot formation in order to better control it. More recently, the need to study soot formation in engine relevant conditions has become apparent. One engine relevant parameter that has had little focus is the ambient pressure. This body of work focuses on the formation of soot in elevated pressure environments, and a number of investigations are carried out with this purpose. Laminar coflow diffusion flames are used as steady, simple soot producers. First, a commonly studied flame configuration is further characterized. Coflow flames are frequently used for fundamental flame studies, particularly at elevated pressures. However, they are more susceptible to buoyancy induced instabilities at elevated pressures. The velocity of the coflow is known to have an effect on flame stability and soot formation, though these have not been characterized at elevated pressures. A series of flames are investigated covering a range of flowrates, pressures, and nozzle diameters. The stability limits of coflow flames in this range is investigated. Additionally, an alternative strategy for scaling these flames to elevated pressures is proposed. Finally, the effect of coflow rate on soot formation is evaluated. Identification of fundamental flames for coordinated research can facilitate our understanding of soot formation. The next study of this work focuses on adding soot concentration and particle size information to an existing fundamental flame dataset for the purpose of numerical model validation. Soot volume fraction and average particle diameters are successfully measured in nitrogen-diluted ethylene-air laminar coflow flames at pressures of 4, 8, 12, and 16 atm. An increase in particle size with pressure is found up to 12 atm, where particle

  1. Effects of DME mixing on number density and size properties of soot particles in counterflow non-premixed ethylene flames

    KAUST Repository

    Choi, J. H.

    2015-05-01

    In order to investigate the effect of DME mixing on the number density and size of soot particles, DME was mixed in a counter flow non-premixed ethylene flame with mixture ratios of 5%, 14% and 30%. A laser extinction/scattering technique has been adopted to measure the volume fraction, number density, and mean size of soot particles. The experimental results showed that the highest soot concentrations were observed for flames with mixture ratios of 5% and 14%; however, for a mixture ratio of 30% the soot concentration decreased. Numerical results showed that the concentrations of propargyl radicals (C3H3) at the 5% and 14% ratios were higher than those measured in the ethylene-based flame, and the production of benzene (C6H6) in the 5% and 14% DME mixture flames was also increased. This indicates the crucial role of propargyl in benzene ring formation. These reactions generally become stronger with increased DME mixing, except for A1- + H2 → A1 + H (-R554) and n-C4H5 + C2H2 → A1 + H (R542). Therefore, it is indicated that adding DME to ethylene flames promotes benzene ring formation. Note that although the maximum C6H6 concentration is largest in the 30% DME mixing flame, the soot volume fraction is smaller than those for the 5% and 14% mixture ratios. This is because the local C6H6 concentration decreases in the relatively low temperature region in the fuel side where soot growth occurs. © 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

  2. Investigating Soot Morphology in Counterflow Flames at Elevated Pressures

    KAUST Repository

    Amin, Hafiz Muhammad Fahid

    2018-01-01

    Practical combustion devices such as gas turbines and diesel engines operate at high pressures to increase their efficiency. Pressure significantly increases the overall soot yield. Morphology of these ultra-fine particles determines their airborne lifetime and their interaction with the human respiratory system. Therefore, investigating soot morphology at high pressure is of practical relevance. In this work, a novel experimental setup has been designed and built to study the soot morphology at elevated pressures. The experimental setup consists of a pressure vessel, which can provide optical access from 10° to 165° for multi-angle light scattering, and a counterflow burner which produces laminar flames at elevated pressures. In the first part of the study, N2-diluted ethylene/air and ethane air counterflow flames are stabilized from 2 to 5 atm. Two-angle light scattering and extinction technique have been used to study the effects of pressure on soot parameters. Path averaged soot volume fraction is found to be very sensitive to pressure and increased significantly from 2 to 5 atm. Primary particle size and aggregate size also increased with pressure. Multi-angle light scattering is also performed and flames are investigated from 3 to 5 atm. Scattering to absorption ratio is calculated from multi-angle light scattering and extinction data. Scattering to absorption ratio increased with pressure whereas the number of primary particles in an aggregate decreased with increasing pressure. In the next part of the study, Thermophoretic Sampling of soot is performed, in counterflow flames from 3 to 10 atm, followed by transmission electron microscopy. Mean primary particle size increased with pressure and these trends are consistent withour light scattering measurements. Fractal properties of soot aggregates are found to be insensitive to pressure. 2D diffused light line of sight attenuation (LOSA) and Laser Induced Incandescence (LII) are used to measure local soot

  3. Investigation of soot optical properties by spectral line-of-sight attenuation

    Energy Technology Data Exchange (ETDEWEB)

    Migliorini, F.; Thomson, K.A.; Smallwood, G.J. [National Research Council of Canada, Ottawa, ON (Canada); Geigle, K.P. [DLR, Stuttgart (Germany). Inst. of Combustion Technology; Johnson, M.J. [Carleton Univ., Ottawa, ON (Canada)

    2009-07-01

    Optical soot diagnostics are a non-intrusive method to measure, understand and hopefully control soot formation. This presentation discussed an investigation of soot optical properties by spectral line-of-sight attenuation. Topics that were presented included optical properties in soot diagnostics; the soot refractive index absorption function E(m); E(m) from the literature; variation of E(m) with wavelength; governing equations; one-dimensional spectral LOSA; the gulder burner; the McKenna burner; zero-dimensional spectral LOSA; relative E(m) for the McKenna burner; and a discussion on relative E(m) in a McKenna flame. It was concluded that future work should include thermophoretic sampling at measurement locations in Gulder and McKenna burner to establish morphology and aging of soot and emission measurements to determine if multi-wavelength pyrometry agrees with multiwavelength attenuation. figs.

  4. Strain rate effect on sooting characteristics in laminar counterflow diffusion flames

    KAUST Repository

    Wang, Yu

    2016-01-20

    The effects of strain rate, oxygen enrichment and fuel type on the sooting characteristics of counterflow diffusion flames were studied. The sooting structures and relative PAH concentrations were measured with laser diagnostics. Detailed soot modeling using recently developed PAH chemistry and surface reaction mechanism was performed and the results were compared with experimental data for ethylene flames, focusing on the effects of strain rates. The results showed that increase in strain rate reduced soot volume fraction, average size and peak number density. Increase in oxygen mole fraction increased soot loading and decreased its sensitivity on strain rate. The soot volume fractions of ethane, propene and propane flames were also measured as a function of global strain rate. The sensitivity of soot volume fraction to strain rate was observed to be fuel dependent at a fixed oxygen mole fraction, with the sensitivity being higher for more sooting fuels. However, when the soot loadings were matched at a reference strain rate for different fuels by adjusting oxygen mole fraction, the dependence of soot loading on strain rate became comparable among the tested fuels. PAH concentrations were shown to decrease with increase in strain rate and the dependence on strain rate is more pronounced for larger PAHs. Soot modeling was performed using detailed PAH growth chemistry with molecular growth up to coronene. A qualitative agreement was obtained between experimental and simulation results, which was then used to explain the experimentally observed strain rate effect on soot growth. However, quantitatively, the simulation result exhibits higher sensitivity to strain rate, especially for large PAHs and soot volume fractions.

  5. Light absorption and morphological properties of soot-containing aerosols observed at an East Asian outflow site, Noto Peninsula, Japan

    Directory of Open Access Journals (Sweden)

    S. Ueda

    2016-03-01

    Full Text Available The coating of black carbon (BC with inorganic salts and organic compounds can enhance the magnitude of light absorption by BC. To elucidate the enhancement of light absorption of aged BC particles and its relation to the mixing state and morphology of individual particles, we conducted observations of particles at an Asian outflow site in Noto Peninsula, Japan, in the spring of 2013. Absorption and scattering coefficients at 405, 532, and 781 nm and mass concentrations/mixing states of refractory BC in PM2.5 were measured using a three-wavelength photoacoustic soot spectrometer and a single-particle soot photometer (SP2, respectively, after passage through a thermodenuder (TD maintained at 300 or 400 °C or a bypass line maintained at room temperature (25 °C. The average enhancement factor of BC light absorption due to coating was estimated by comparing absorption coefficients at 781 nm for particles that with and without passing through the TD at 300 °C and was found to be 1.22. The largest enhancements (> 1.30 were observed under high absorption coefficient periods when the air mass was long-range transported from urban areas in China. Aerosol samples were also analyzed using a transmission electron microscope (TEM equipped with an energy dispersive X-ray analyzer. The morphological features and mixing states of soot-containing particles of four samples collected during the high absorption events were analyzed by comparing microphotographs before and after the evaporation of beam-sensitive materials by irradiation with a high-density electron beam. The majority of the soot in all samples was found as mixed particles with sulfate-containing spherules or as clusters of such spherules. For samples showing high enhancement (> 1.30 of BC light absorption, the TEM showed that the internally mixed soot-containing particles tended to have a more spherical shape and to be thickly coated. The SP2 measurements also suggested that the

  6. Light absorption and morphological properties of soot-containing aerosols observed at an East Asian outflow site, Noto Peninsula, Japan

    Science.gov (United States)

    Ueda, Sayako; Nakayama, Tomoki; Taketani, Fumikazu; Adachi, Kouji; Matsuki, Atsushi; Iwamoto, Yoko; Sadanaga, Yasuhiro; Matsumi, Yutaka

    2016-03-01

    The coating of black carbon (BC) with inorganic salts and organic compounds can enhance the magnitude of light absorption by BC. To elucidate the enhancement of light absorption of aged BC particles and its relation to the mixing state and morphology of individual particles, we conducted observations of particles at an Asian outflow site in Noto Peninsula, Japan, in the spring of 2013. Absorption and scattering coefficients at 405, 532, and 781 nm and mass concentrations/mixing states of refractory BC in PM2.5 were measured using a three-wavelength photoacoustic soot spectrometer and a single-particle soot photometer (SP2), respectively, after passage through a thermodenuder (TD) maintained at 300 or 400 °C or a bypass line maintained at room temperature (25 °C). The average enhancement factor of BC light absorption due to coating was estimated by comparing absorption coefficients at 781 nm for particles that with and without passing through the TD at 300 °C and was found to be 1.22. The largest enhancements (> 1.30) were observed under high absorption coefficient periods when the air mass was long-range transported from urban areas in China. Aerosol samples were also analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. The morphological features and mixing states of soot-containing particles of four samples collected during the high absorption events were analyzed by comparing microphotographs before and after the evaporation of beam-sensitive materials by irradiation with a high-density electron beam. The majority of the soot in all samples was found as mixed particles with sulfate-containing spherules or as clusters of such spherules. For samples showing high enhancement (> 1.30) of BC light absorption, the TEM showed that the internally mixed soot-containing particles tended to have a more spherical shape and to be thickly coated. The SP2 measurements also suggested that the proportion of thickly coated

  7. Water interaction with hydrophobic and hydrophilic soot particles.

    Science.gov (United States)

    Popovicheva, Olga; Persiantseva, Natalia M; Shonija, Natalia K; DeMott, Paul; Koehler, Kirsten; Petters, Markus; Kreidenweis, Sonia; Tishkova, Victoria; Demirdjian, Benjamin; Suzanne, Jean

    2008-05-07

    The interaction of water with laboratory soots possessing a range of properties relevant for atmospheric studies is examined by two complementary methods: gravimetrical measurement of water uptake coupled with chemical composition and porosity analysis and HTDMA (humidified tandem differential mobility analyzer) inference of water uptake accompanied by separate TEM (transmission electron microscopy) analysis of single particles. The first method clarifies the mechanism of water uptake for bulk soot and allows the classification of soot with respect to its hygroscopicity. The second method highlights the dependence of the soot aerosol growth factor on relative humidity (RH) for quasi-monodisperse particles. Hydrophobic and hydrophilic soot are qualitatively defined by their water uptake and surface polarity: laboratory soot particles are thus classified from very hydrophobic to very hydrophilic. Thermal soot particles produced from natural gas combustion are classified as hydrophobic with a surface of low polarity since water is found to cover only half of the surface. Graphitized thermal soot particles are proposed for comparison as extremely hydrophobic and of very low surface polarity. Soot particles produced from laboratory flame of TC1 aviation kerosene are less hydrophobic, with their entire surface being available for statistical monolayer water coverage at RH approximately 10%. Porosity measurements suggest that, initially, much of this surface water resides within micropores. Consequently, the growth factor increase of these particles to 1.07 at RH > 80% is attributed to irreversible swelling that accompanies water uptake. Hysteresis of adsorption/desorption cycles strongly supports this conclusion. In contrast, aircraft engine soot, produced from burning TC1 kerosene in a gas turbine engine combustor, has an extremely hydrophilic surface of high polarity. Due to the presence of water soluble organic and inorganic material it can be covered by many water

  8. Formation of Soot in Counterflow Diffusion Flames with Carbon Dioxide Dilution

    KAUST Repository

    Wang, Yu

    2016-05-04

    Experimental and numerical modeling studies have been performed to investigate the effect of CO2 dilution on soot formation in ethylene counterflow diffusion flames. Thermal and chemical effects of CO2 addition on soot growth was numerically identified by using a fictitious CO2 species, which was treated as inert in terms of chemical reactions. The results showed that CO2 addition reduces soot formation both thermodynamically and chemically. In terms of chemical effect, the addition of CO2 decreases soot formation through various pathways, including: (1) reduced soot precursor (PAH) formation leading to lower inception rates and soot number density, which in turn results in lower surface area for soot mass addition; (2) reduced H, CH3, and C3H3 concentrations causing lower H abstraction rate and therefore less active site per surface area for soot growth; and (3) reduced C2H2 mole fraction and thus a slower C2H2 mass addition rate. In addition, the sooting limits were also measured for ethylene counterflow flames in both N2 and CO2 atmosphere and the results showed that sooting region was significantly reduced in the CO2 case compared to the N2 case. © 2016 Taylor & Francis.

  9. Modelling soot formation from wall films in a gasoline direct injection engine using a detailed population balance model

    International Nuclear Information System (INIS)

    Wang, Buyu; Mosbach, Sebastian; Schmutzhard, Sebastian; Shuai, Shijin; Huang, Yaqing; Kraft, Markus

    2016-01-01

    Highlights: • Soot formation from a wall film in a GDI engine is simulated. • Spray impingement and wall film evaporation models are added to SRM Engine Suite. • Soot is modelled using a highly detailed population balance model. • Particle size distributions are measured experimentally. • Evolution of wall region is shown in equivalence ratio-temperature diagrams. - Abstract: In this study, soot formation in a Gasoline Direct Injection (GDI) engine is simulated using a Stochastic Reactor Model (SRM Engine Suite) which contains a detailed population balance soot model capable of describing particle morphology and chemical composition. In order to describe the soot formation originating from the wall film, the SRM Engine Suite is extended to include spray impingement and wall film evaporation models. The cylinder is divided into a wall and a bulk zone to resolve the equivalence ratio and temperature distributions of the mixture near the wall. The combustion chamber wall is assumed to exchange heat directly only with the wall zone. The turbulent mixing within each zone and between the two zones are simulated with different mixing models. The effects of key parameters on the temperature and equivalence ratio in the two zones are investigated. The mixing rate between the wall and bulk zone has a significant effect on the wall zone, whilst the mixing rate in the wall zone only has a negligible impact on the temperature and equivalence ratio below a certain threshold. Experimental data are obtained from a four-cylinder, gasoline-fuelled direct injection spark ignition engine operated stoichiometrically. An injection timing sweep, ranging from 120 CAD BTDC to 330 CAD BTDC, is conducted in order to investigate the effect of spray impingement on soot formation. The earliest injection case (330 CAD BTDC), which produces significantly higher levels of particle emissions than any other case, is simulated by the current model. It is found that the in-cylinder pressure

  10. Conductometric Sensor for Soot Mass Flow Detection in Exhausts of Internal Combustion Engines.

    Science.gov (United States)

    Feulner, Markus; Hagen, Gunter; Müller, Andreas; Schott, Andreas; Zöllner, Christian; Brüggemann, Dieter; Moos, Ralf

    2015-11-13

    Soot sensors are required for on-board diagnostics (OBD) of automotive diesel particulate filters (DPF) to detect filter failures. Widely used for this purpose are conductometric sensors, measuring an electrical current or resistance between two electrodes. Soot particles deposit on the electrodes, which leads to an increase in current or decrease in resistance. If installed upstream of a DPF, the "engine-out" soot emissions can also be determined directly by soot sensors. Sensors were characterized in diesel engine real exhausts under varying operation conditions and with two different kinds of diesel fuel. The sensor signal was correlated to the actual soot mass and particle number, measured with an SMPS. Sensor data and soot analytics (SMPS) agreed very well, an impressing linear correlation in a double logarithmic representation was found. This behavior was even independent of the used engine settings or of the biodiesel content.

  11. Soot Formation Modeling of n-dodecane and Diesel Sprays under Engine-Like Conditions

    DEFF Research Database (Denmark)

    Pang, Kar Mun; Poon, Hiew Mun; Ng, Hoon Kiat

    2015-01-01

    multi-step soot model is validated by comparing to the experimental data of n-dodecane fuel in which the associated chemistry is better understood. In the diesel spray simulations, a single component n-heptane mechanism and the multi-component Diesel Oil Surrogate (DOS) model are adopted. A newly...... developed C16-based model which comprises skeletal mechanisms of n-hexadecane, heptamethylnonane, cyclohexane and toluene is also implemented. Comparisons of the results show that the simulated liftoff lengths are reasonably well-matched to the experimental measurement, where the relative differences...... are retained to below 18%. Only that predicted by the DOS model in the 900 K case is overestimated by approximately 28%. The experimental maximum soot volume fraction (SVF) rises by approximately 7.0 fold as the ambient temperature is raised from 900 K to 1000 K. The ratio calculated by chemical mechanisms...

  12. The reduction of soot formation from fuels using oxygenates additives

    International Nuclear Information System (INIS)

    Burshaid, K.I.; Hamdan, M.A.

    2013-01-01

    Highlights: ► Understanding of the performance of thermo chemical heat pump. ► Tool for storing thermal energy. ► Parameters that affect the amount of thermal stored energy. ► Lithium chloride has better effect on storing thermal energy. - Abstract: This work presents an experimental technique for the measurement of the soot formation in pure fuel, biofuel and emulsified fuel, that constitute this fuels was studied in heated shock tube and investigated the possibility of reducing soot production in locally refined diesel, locally produced biofuel and emulsified fuel. This reduction was conducted using certain oxygenated additives (methane, ethane and acetone). It was found that soot concentration is maximum when pure diesel was burned, followed by emulsified fuels and the lease concentration was obtained when biofuel was burned. Further, methanol has the most significant effect on the reduction of soot once added to each fuel, while acetone has the lease effect on soot reduction. The results gave good indication of the effect for oxygenated additives in reduction the soot formation.

  13. Durable superhydrophobic carbon soot coatings for sensor applications

    Science.gov (United States)

    Esmeryan, K. D.; Radeva, E. I.; Avramov, I. D.

    2016-01-01

    A novel approach for the fabrication of durable superhydrophobic (SH) carbon soot coatings used in quartz crystal microbalance (QCM) based gas or liquid sensors is reported. The method uses modification of the carbon soot through polymerization of hexamethyldisiloxane (HMDSO) by means of glow discharge RF plasma. The surface characterization shows a fractal-like network of carbon nanoparticles with diameter of ~50 nm. These particles form islands and cavities in the nanometer range, between which the plasma polymerized hexamethyldisiloxane (PPHMDSO) embeds and binds to the carbon chains and QCM surface. Such modified surface structure retains the hydrophobic nature of the soot and enhances its robustness upon water droplet interactions. Moreover, it significantly reduces the insertion loss and dynamic resistance of the QCM compared to the commonly used carbon soot/epoxy resin approach. Furthermore, the PPHMDSO/carbon soot coating demonstrates durability and no aging after more than 40 probing cycles in water based liquid environments. In addition, the surface layer keeps its superhydrophobicity even upon thermal annealing up to 540 °C. These experiments reveal an opportunity for the development of soot based SH QCMs with improved electrical characteristics, as required for high-resolution gas or liquid measurements.

  14. Durable superhydrophobic carbon soot coatings for sensor applications

    International Nuclear Information System (INIS)

    Esmeryan, K D; Radeva, E I; Avramov, I D

    2016-01-01

    A novel approach for the fabrication of durable superhydrophobic (SH) carbon soot coatings used in quartz crystal microbalance (QCM) based gas or liquid sensors is reported. The method uses modification of the carbon soot through polymerization of hexamethyldisiloxane (HMDSO) by means of glow discharge RF plasma. The surface characterization shows a fractal-like network of carbon nanoparticles with diameter of ∼50 nm. These particles form islands and cavities in the nanometer range, between which the plasma polymerized hexamethyldisiloxane (PPHMDSO) embeds and binds to the carbon chains and QCM surface. Such modified surface structure retains the hydrophobic nature of the soot and enhances its robustness upon water droplet interactions. Moreover, it significantly reduces the insertion loss and dynamic resistance of the QCM compared to the commonly used carbon soot/epoxy resin approach. Furthermore, the PPHMDSO/carbon soot coating demonstrates durability and no aging after more than 40 probing cycles in water based liquid environments. In addition, the surface layer keeps its superhydrophobicity even upon thermal annealing up to 540 °C. These experiments reveal an opportunity for the development of soot based SH QCMs with improved electrical characteristics, as required for high-resolution gas or liquid measurements. (paper)

  15. In-cylinder Combustion and Soot Evolution in the Transition from Conventional CI mode to PPC

    KAUST Repository

    An, Yanzhao

    2018-01-09

    The present study intends to explore the in-cylinder combustion and evolution of soot emission during the transition from conventional compression ignition (CI) combustion to partially premixed combustion (PPC) at low load conditions. In-cylinder combustion images and engine-out emissions were measured in an optical engine fueled with low octane heavy naphtha fuel (RON = 50). Full cycle engine simulations were performed using a three-dimensional computational fluid dynamics code CONVERGETM, coupled with gas phase chemical kinetics, turbulence, and particulate size mimic soot model. The simulations were performed under low load conditions (IMEP ~ 2 to 3 bar) at an engine speed of 1200 rpm. The start of injection (SOI) was advanced from late (-10 CAD aTDC) to early fuel injection timings (-40 CAD aTDC) to realize the combustion transition from CI combustion to PPC. The simulation results of combustion and emission are compared with the experimental results at both CI and PPC combustion modes. The results of the study show a typical low-temperature stratified lean combustion at PPC mode, while high-temperature spray-driven combustion is evident at CI mode. The in-cylinder small intermediates species such as acetylene (C2H2), propargyl (C3H3), cyclopentadienyl (C5H5) and polycyclic aromatic hydrocarbons (PAHs) were significantly suppressed at PPC mode. Nucleation reaction of PAHs collision contributed to main soot mass production. The distribution of soot mass and particle number density was consistent with the distribution of high-temperature zones at CI and PPC combustion modes.

  16. Comparative Study of Different Methods for Soot Sensing and Filter Monitoring in Diesel Exhausts

    Directory of Open Access Journals (Sweden)

    Markus Feulner

    2017-02-01

    Full Text Available Due to increasingly tighter emission limits for diesel and gasoline engines, especially concerning particulate matter emissions, particulate filters are becoming indispensable devices for exhaust gas after treatment. Thereby, for an efficient engine and filter control strategy and a cost-efficient filter design, reliable technologies to determine the soot load of the filters and to measure particulate matter concentrations in the exhaust gas during vehicle operation are highly needed. In this study, different approaches for soot sensing are compared. Measurements were conducted on a dynamometer diesel engine test bench with a diesel particulate filter (DPF. The DPF was monitored by a relatively new microwave-based approach. Simultaneously, a resistive type soot sensor and a Pegasor soot sensing device as a reference system measured the soot concentration exhaust upstream of the DPF. By changing engine parameters, different engine out soot emission rates were set. It was found that the microwave-based signal may not only indicate directly the filter loading, but by a time derivative, the engine out soot emission rate can be deduced. Furthermore, by integrating the measured particulate mass in the exhaust, the soot load of the filter can be determined. In summary, all systems coincide well within certain boundaries and the filter itself can act as a soot sensor.

  17. Temperature measurement of accelerator cell solenoid loop

    International Nuclear Information System (INIS)

    Mu Fan; Dong Pan; Dai Zhiyong

    2010-01-01

    This paper presents the research on temperature measurement of solenoid loop. The measuring temperature fiber is layered in solenoid loop for the accelerator cell. When the solenoid loop is supplied with high current form a constant current source, its temperature increases rapidly. The temperature fiber can measure the temperature of the solenoid loop and get temperature measurement rule. Experiment and simulation show temperature of interior solenoid loop the highest and it decreases from the interior to the exterior of solenoid loop. To control temperature of solenoid loop under 60 degree C, simulation displays load interval of constant current source with 80 A current should be at least is 17.5 minutes. (authors)

  18. Laser Pyrometer For Spot Temperature Measurements

    Science.gov (United States)

    Elleman, D. D.; Allen, J. L.; Lee, M. C.

    1988-01-01

    Laser pyrometer makes temperature map by scanning measuring spot across target. Scanning laser pyrometer passively measures radiation emitted by scanned spot on target and calibrated by similar passive measurement on blackbody of known temperature. Laser beam turned on for active measurements of reflectances of target spot and reflectance standard. From measurements, temperature of target spot inferred. Pyrometer useful for non-contact measurement of temperature distributions in processing of materials.

  19. Numerical modeling of soot formation in a turbulent C2H4/air diffusion flame

    Directory of Open Access Journals (Sweden)

    Manedhar Reddy Busupally

    2016-06-01

    Full Text Available Soot formation in a lifted C2H4-Air turbulent diffusion flame is studied using two different paths for soot nucleation and oxidation; by a 2D axisymmetric RANS simulation using ANSYS FLUENT 15.0. The turbulence-chemistry interactions are modeled using two different approaches: steady laminar flamelet approach and flamelet-generated manifold. Chemical mechanism is represented by POLIMI to study the effect of species concentration on soot formation. P1 approximation is employed to approximate the radiative transfer equation into truncated series expansion in spherical harmonics while the weighted sum of gray gases is invoked to model the absorption coefficient while the soot model accounts for nucleation, coagulation, surface growth, and oxidation. The first route for nucleation considers acetylene concentration as a linear function of soot nucleation rate, whereas the second route considers two and three ring aromatic species as function of nucleation rate. Equilibrium-based and instantaneous approach has been used to estimate the OH concentration for soot oxidation. Lee and Fenimore-Jones soot oxidation models are studied to shed light on the effect of OH on soot oxidation. Moreover, the soot-radiation interactions are also included in terms of absorption coefficient of soot. Furthermore, the soot-turbulence interactions have been invoked using a temperature/mixture fraction-based single variable PDF. Both the turbulence-chemistry interaction models are able to accurately predict the flame liftoff height, and for accurate prediction of flame length, radiative heat loss should be accounted in an accurate way. The soot-turbulence interactions are found sensitive to the PDF used in present study.

  20. Latitudinal distribution of black carbon soot in the upper troposphere and lower stratosphere

    Science.gov (United States)

    Blake, David F.; Kato, Katharine

    1995-01-01

    Black carbon soot from the upper troposphere and lower stratosphere has been systematically collected at latitudes from 90 deg N to 45 deg S. The measured latitudinal distribution of this soot at 10 to 11 km altitude is found to covary with commercial air traffic fuel use, suggesting that aircraft fuel combustion at altitude is the principal source. In addition, at latitudes where the commercial air traffic is high, measured black carbon soot values are high even at 20 km altitude, suggesting that aircraft-generated soot injected just above the tropopause may be transported to higher altitudes. During the volcanically influenced period in which these samples were collected, the number abundances, total mass, and calculated total surface area of black carbon soot are 2-3 orders of magnitude lower than similar measures of sulfuric acid aerosol. During volcanically quiescent periods, the calculated total surface area of black carbon soot aerosol is of the same order of magnitude as that of the background sulfuric acid aerosol. It appears from this comparison that black carbon soot is only capable of influencing lower stratosphere or upper troposphere chemistry during periods when the aerosol budget is not dominated by volcanic activity. It remains to determine the extent to which black carbon soot particles act as nuclei for sulfuric acid aerosol formation. However, mass balance calculations suggest that aircraft soot injected at altitude does not represent a significant source of condensation nuclei for sulfuric acid aerosols.

  1. Impacts of fuel formulation and engine operating parameters on the nanostructure and reactivity of diesel soot

    Science.gov (United States)

    Yehliu, Kuen

    This study focuses on the impacts of fuel formulations on the reactivity and nanostructure of diesel soot. A 2.5L, 4-cylinder, turbocharged, common rail, direct injection light-duty diesel engine was used in generating soot samples. The impacts of engine operating modes and the start of combustion on soot reactivity were investigated first. Based on preliminary investigations, a test condition of 2400 rpm and 64 Nm, with single and split injection strategies, was chosen for studying the impacts of fuel formulation on the characteristics of diesel soot. Three test fuels were used: an ultra low sulfur diesel fuel (BP15), a pure soybean methyl-ester (B100), and a synthetic Fischer-Tropsch fuel (FT) produced in a gas-to-liquid process. The start of injection (SOI) and fuel rail pressures were adjusted such that the three test fuels have similar combustion phasing, thereby facilitating comparisons between soots from the different fuels. Soot reactivity was investigated by thermogravimetric analysis (TGA). According to TGA, B100 soot exhibits the fastest oxidation on a mass basis followed by BP15 and FT derived soots in order of apparent rate constant. X-ray photoelectron spectroscopy (XPS) indicates no relation between the surface oxygen content and the soot reactivity. Crystalline information for the soot samples was obtained using X-ray diffraction (XRD). The basal plane diameter obtained from XRD was inversely related to the apparent rate constants for soot oxidation. For comparison, high resolution transmission electron microscopy (HRTEM) provided images of the graphene layers. Quantitative image analysis proceeded by a custom algorithm. B100 derived soot possessed the shortest mean fringe length and greatest mean fringe tortuosity. This suggests soot (nano)structural disorder correlates with a faster oxidation rate. Such results are in agreement with the X-ray analysis, as the observed fringe length is a measure of basal plane diameter. Moreover the relation

  2. Two-dimensional temperature and carbon dioxide concentration profiles in atmospheric laminar diffusion flames measured by mid-infrared direct absorption spectroscopy at 4.2 μm

    Science.gov (United States)

    Liu, Xunchen; Zhang, Guoyong; Huang, Yan; Wang, Yizun; Qi, Fei

    2018-04-01

    We present a multi-line flame thermometry technique based on mid-infrared direct absorption spectroscopy of carbon dioxide at its v_3 fundamental around 4.2 μm that is particularly suitable for sooting flames. Temperature and concentration profiles of gas phase molecules in a flame are important characteristics to understand its flame structure and combustion chemistry. One of the standard laboratory flames to analyze polycyclic aromatic hydrocarbons (PAH) and soot formation is laminar non-premixed co-flow flame, but PAH and soot introduce artifact to most non-contact optical measurements. Here we report an accurate diagnostic method of the temperature and concentration profiles of CO2 in ethylene diffusion flames by measuring its v_3 vibrational fundamental. An interband cascade laser was used to probe the R-branch bandhead at 4.2 μm, which is highly sensitive to temperature change, free from soot interference and ambient background. Calibration measurement was carried out both in a low-pressure Herriott cell and an atmospheric pressure tube furnace up to 1550 K to obtain spectroscopic parameters for high-temperature spectra. In our co-flow flame measurement, two-dimensional line-of-sight optical depth of an ethylene/N2 laminar sooting flame was recorded by dual-beam absorption scheme. The axially symmetrical attenuation coefficient profile of CO2 in the co-flow flame was reconstructed from the optical depth by Abel inversion. Spatially resolved flame temperature and in situ CO2 volume fraction profiles were derived from the calibrated CO2 spectroscopic parameters and compared with temperature profiles measured by two-line atomic fluorescence.

  3. Effect of NO2 and water on the catalytic oxidation of soot

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Grunwaldt, Jan-Dierk; Jensen, Anker Degn

    2017-01-01

    The influence of adding NO2 to 10 vol% O2/N2 on non-catalytic soot oxidation and soot oxidation in intimate or loose contact with a catalyst has been investigated. In non-catalytic soot oxidation the oxidation rate is increased significantly at lower temperatures by NO2. For soot oxidation in tig...... exhibited a volcano-curve dependence on the heat of oxygen chemisorption, and among the tested pure metals and oxides Cr2O3 was the most active catalyst. Further improvements were achieved with a FeaCrbOx binary oxide catalyst.......The influence of adding NO2 to 10 vol% O2/N2 on non-catalytic soot oxidation and soot oxidation in intimate or loose contact with a catalyst has been investigated. In non-catalytic soot oxidation the oxidation rate is increased significantly at lower temperatures by NO2. For soot oxidation in tight...... contact with a Co3O4 catalyst a more reactive NO2-containg atmosphere did not change the oxidation profile significantly during temperature programmed oxidation. This is consistent with the expected Mars van Krevelen mechanism, where the rate limiting step is reaction between carbon and lattice oxygen...

  4. A mechanistic study on the simultaneous elimination of soot and nitric oxide from engine exhaust

    KAUST Repository

    Raj, Abhijeet

    2011-04-01

    The non-catalytic interaction between soot and nitric oxide (NO) resulting in their simultaneous elimination was studied on different types of reactive site present on soot. The reaction mechanism proposed previously was extended by including seven new reaction pathways for which the reaction energetics and kinetics were studied using density functional theory and transition state theory. This has led to the calculation of a new rate for the removal of carbon monoxide (CO) from soot. The new pathways have been added to our polycyclic aromatic hydrocarbon (PAH) growth model and used to simulate the NO-soot interaction to form CO, N2 and N2O. The simulation results show satisfactory agreement with experiment for the new CO removal rate. The NO-soot reaction was found to depend strongly on the soot site type and temperature. For a set of temperatures, computed PAH structures were analysed to determine the functional groups responsible for the decrease in the reactivity of soot with NO with increasing reaction time. In isothermal conditions, it was found that as temperature is increased, the number of oxygen atoms remaining on the soot surface decreases, while the number of nitrogen atoms increases for a given reaction time. © 2010 Elsevier Ltd. All rights reserved.

  5. New algorithm for extreme temperature measurements

    NARCIS (Netherlands)

    Damean, N.

    2000-01-01

    A new algorithm for measurement of extreme temperature is presented. This algorithm reduces the measurement of the unknown temperature to the solving of an optimal control problem, using a numerical computer. Based on this method, a new device for extreme temperature measurements is projected. It

  6. Soot formation characteristics of gasoline surrogate fuels in counterflow diffusion flames

    KAUST Repository

    Choi, Byungchul

    2011-01-01

    The characteristics of polycyclic aromatic hydrocarbon (PAH) and soot for gasoline surrogate fuels have been investigated in counterflow diffusion flames by adopting laser-induced fluorescence (LIF) and laser-induced incandescence (LII) techniques for both soot formation and soot formation/oxidation flames. Tested fuels were three binary mixtures from the primary reference fuels of n-heptane, iso-octane, and toluene. The result showed that PAH and soot maintained near zero level for all mixtures of n-heptane/iso-octane case under present experimental conditions. For n-heptane/toluene and iso-octane/toluene mixtures, PAH initially increased and then decreased with the toluene ratio, exhibiting a synergistic effect. The soot formation increased monotonically with the toluene ratio, however the effect of toluene on soot formation was minimal for relatively small toluene ratios. These results implied that even though toluene had a dominant role in soot and PAH formations, small amount of toluene had a minimal effect on soot formation. Numerical simulations have also been conducted by adopting recently proposed two kinetic mechanisms. The synergistic behavior of aromatic rings was predicted similar to the experimental PAH measurement, however, the degree of the synergistic effect was over-predicted for the soot formation flame, indicating the need for refinements in the kinetic mechanisms. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  7. Soot reduction under DC electric fields in counterflow non-premixed laminar ethylene flames

    KAUST Repository

    Park, Daegeun

    2014-04-23

    The effects of DC electric fields on non-premixed ethylene flames in a counterflow burner were studied experimentally with a focus on the reduction of soot particles. The experiment was conducted by connecting a high voltage terminal and a ground terminal to a lower (fuel) and upper (oxidizer) nozzle, respectively. We applied direct current (DC) potentials in a range of -5 kV < Vdc < 5 kV. Uniform electric fields were then generated in the gap between the two nozzles. The experimental conditions were selected to cover both soot formation (SF) and soot formation oxidation (SFO) flames. The flames subjected to the negative electric fields moved toward the fuel nozzle because of an ionic wind due to the Lorentz force acting on the positive ions in the flames. In addition, the yellow luminosity significantly decreased, indicating changes in the sooting characteristics. To analyze the sooting characteristics under the electric fields, planar laser induced incandescence (PLII) and fluorescence (PLIF) techniques were used to visualize the soot, polycyclic aromatic hydrocarbons (PAHs), and OH radicals. The sooting limits in terms of the fuel and oxygen mole fractions were measured. No substantial soot formation due to the effects of the DC electric fields for the tested range of voltages and reactant mole fractions could be identified. The detailed flame behaviors and sooting characteristics under the DC electric fields are discussed. Copyright © Taylor & Francis Group, LLC.

  8. On Soot Inception in Nonpremixed Flames and the Effects of Flame Structure

    Science.gov (United States)

    Chao, B. H.; Liu, S.; Axelbaum, R. L.; Gokoglu, Suleyman (Technical Monitor)

    1998-01-01

    A simplified three-step model of soot inception has been employed with high activation energy asymptotics to study soot inception in nonpremixed counterflow systems with emphasis on understanding the effects of hydrodynamics and transport. The resulting scheme yields three zones: (1) a fuel oxidation zone wherein the fuel and oxidizer react to form product as well as a radical R, (e.g., H), (2) a soot/precursor formation zone where the radical R reacts with fuel to form "soot/precursor" S, and (3) a soot/precursor consumption zone where S reacts with the oxidizer to form product. The kinetic scheme, although greatly simplified, allows the coupling between soot inception and flame structure to be assessed. The results yield flame temperature, flame location, and a soot/precursor index S(sub I) as functions of Damkohler number for S formation. The soot/precursor index indicates the amount of S at the boundary of the formation region. The flame temperature indirectly indicates the total amount of S integrated over the formation region because as S is formed less heat release is available. The results show that unlike oxidation reactions, an extinction turning-point behavior does not exist for soot. Instead, the total amount of S slowly decreases with decreasing Damkohler number (increasing strain rate), which is consistent with counterflow flame experiments. When the Lewis number of the radical is decreased from unity, the total S reduces due to reduced residence time for the radical in the soot formation region. Similarly, when the Lewis number of the soot/precursor is increased from unity the amount of S increases for all Damkohler numbers. In addition to studying fuel-air (low stoichiometric mixture fraction) flames, the air-side nitrogen was substituted into the fuel, yielding diluted fuel-oxygen (high stoichiometric mixture fraction) flames with the same flame temperature as the fuel - air flames. The relative flame locations were different however, and

  9. Aromatics oxidation and soot formation in flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  10. A Review on Diesel Soot Emission, its Effect and Control

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-01-01

    Full Text Available The diesel engines are energy efficient, but their particulate (soot emissions are responsible of severe environmental and health problems. This review provides a survey on published information regarding diesel soot emission, its adverse effects on the human health, environment, vegetations, climate, etc. The legislations to limit diesel emissions and ways to minimize soot emission are also summarized. Soot particles are suspected to the development of cancer; cardiovascular and respiratory health effects; pollution of air, water, and soil; impact agriculture productivity, soiling of buildings; reductions in visibility; and global climate change. The review covers important recent developments on technologies for control of particulate matter (PM; diesel particulate filters (DPFs, summarizing new filter and catalyst materials and DPM measurement. DPF technology is in a state of optimization and cost reduction. New DPF regeneration strategies (active, passive and plasma-assisted regenerations as well as the new learning on the fundamentals of soot/catalyst interaction are described. Recent developments in diesel oxidation catalysts (DOC are also summarized showing potential issues with advanced combustion strategies, important interactions on NO2 formation, and new formulations for durability. Finally, systematic compilation of the concerned newer literature on catalytic oxidation of soot in a well conceivable tabular form is given. A total of 156 references are cited. ©2010 BCREC UNDIP. All rights reserved(Received: 2nd June 2010, Revised: 17th June 2010; Accepted: 24th June 2010[How to Cite: R. Prasad, V.R. Bella. (2010. Review on Diesel Soot Emission, its Effect and Control. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2: 69-86. doi:10.9767/bcrec.5.2.794.69-86][DOI: http://dx.doi.org/10.9767/bcrec.5.2.794.69-86 || or local:   http://ejournal.undip.ac.id/index.php/bcrec/article/view/794 ]Cited by in: ACS 1 |

  11. The Role of Biogenic and Anthropogenic Hydrocarbons in Aging of Atmospheric Soot

    Science.gov (United States)

    Khalizov, A. F.; Qiu, C.; Lin, Y.; Ma, Y.; Wang, L.; Zhang, R.

    2012-12-01

    Atmospheric soot is often found to be internally mixed with other aerosol constituents, yet the processes responsible for the soot aging are not well understood. We have conducted a systematic study on the role of several representative biogenic and anthropogenic volatile organic compounds (VOCs), including monoterpenes and aromatics, in atmospheric aging of combustion soot. Aging experiments were conducted in a fluoropolymer chamber on size-classified soot aerosols in the presence of a VOC and an oxidant, either ozone or photolytically generated hydroxyl radical (OH). The evolution in the aging state of soot was monitored from measurements of the particle mobility size and mass, which were used to derive information about particle effective density, dynamic shape factor, and coating thickness. When exposed to VOC and oxidant, soot particles promptly gain mass due to condensation of low-volatility and partitioning of semi-volatile VOC oxidation products. Depending on the VOC, the increase in the particle mass is accompanied by an increase or a decrease in the particle mobility diameter. In either case, the effective density of coated soot particles increases during aging because the condensed material fills in the voids of fractal soot aggregates, forcing their restructuring. The latter is confirmed by thermal denuding experiments, which show an increase in the effective density for soot that was first aged and then heated to remove the coating from the soot core. Hygroscopic and optical properties of soot are significantly altered by aging. Upon humidification, the coating absorbs water, increasing in volume and causing an additional restructuring of soot aggregates. Coated particles are sufficiently hygroscopic to activate to cloud droplets at atmospherically relevant water supersaturations. Aged soot shows stronger light absorption and scattering, with an enhancement magnitude depending on the coating thickness and nature of the coating precursor. The rate of

  12. Morphology and nano-structure analysis of soot particles sampled from high pressure diesel jet flames under diesel-like conditions

    Science.gov (United States)

    Jiang, Hao; Li, Tie; Wang, Yifeng; He, Pengfei

    2018-04-01

    Soot particles emitted from diesel engines have a significant impact on the atmospheric environment. Detailed understanding of soot formation and oxidation processes is helpful for reducing the pollution of soot particles, which requires information such as the size and nano-structure parameters of the soot primary particles sampled in a high-temperature and high-pressure diesel jet flame. Based on the thermophoretic principle, a novel sampling probe minimally disturbing the diesel jet flame in a constant volume combustion vessel is developed for analysing soot particles. The injected quantity of diesel fuel is less than 10 mg, and the soot particles sampled by carriers with a transmission electron microscope (TEM) grid and lacey TEM grid can be used to analyse the morphologies of soot aggregates and the nano-structure of the soot primary particles, respectively. When the quantity of diesel fuel is more than 10 mg, in order to avoid burning-off of the carriers in higher temperature and pressure conditions, single-crystal silicon chips are employed. Ultrasonic oscillations and alcohol extraction are then implemented to obtain high quality soot samples for observation using a high-resolution transmission electron microscope. An in-house Matlab-based code is developed to extract the nano-structure parameters of the soot particles. A complete sampling and analysis procedure of the soot particles is provided to study the formation and oxidation mechanism of soot.

  13. Microscopic investigation of soot and ash particulate matter derived from biofuel and diesel: implications for the reactivity of soot

    Science.gov (United States)

    Liati, Anthi; Spiteri, Alexander; Dimopoulos Eggenschwiler, Panayotis; Vogel-Schäuble, Nina

    2012-11-01

    Investigation of soot and ash particulate matter deposited in diesel particulate filters (DPFs) operating with biofuel (B100) and diesel (pure diesel: B0 and diesel80/biofuel20 blend: B20) by means of optical microscopy, scanning electron microscopy, and high resolution transmission electron microscopy (HRTEM) reveals the following: the rapeseed methyl ester biofuel used for this study contributes to ash production, mainly of Ca-S- and P-bearing compounds ranging in size between 50 and 300 nm. Smaller ash particles are less common and build aggregates. Ash is deposited on the inlet DPF surface, the inlet channel walls, and in B100-DPF at the plugged ends of inlet channels. The presence of Fe-Cr-Ni fragments, down to tens of nanometers in size within the ash is attributed to engine wear. Pt particles (50-400 nm large) within the ash indicate that the diesel oxidation catalyst (DOC) upstream of the DPF shows aging effects. Radial cracks on the coating layer of the DOC confirm this assumption. The B100-DPF contains significantly less soot than B20 and B0. Based on the generally accepted view that soot reactivity correlates with the nanostructure of its primary particles, the length and curvature of graphene sheets from biofuel- and diesel-derived soot were measured and computed on the basis of HRTEM images. The results show that biofuel-derived soot can be more easily oxidized than diesel soot, not only during early formation but also during and after considerable particle growth. Differences in the graphene sheet separation distance, degree of crystalline order and size of primary soot particles between the two fuel types are in line with this inference.

  14. Microscopic investigation of soot and ash particulate matter derived from biofuel and diesel: implications for the reactivity of soot

    International Nuclear Information System (INIS)

    Liati, Anthi; Spiteri, Alexander; Dimopoulos Eggenschwiler, Panayotis; Vogel-Schäuble, Nina

    2012-01-01

    Investigation of soot and ash particulate matter deposited in diesel particulate filters (DPFs) operating with biofuel (B100) and diesel (pure diesel: B0 and diesel 80 /biofuel 20 blend: B20) by means of optical microscopy, scanning electron microscopy, and high resolution transmission electron microscopy (HRTEM) reveals the following: the rapeseed methyl ester biofuel used for this study contributes to ash production, mainly of Ca–S– and P-bearing compounds ranging in size between 50 and 300 nm. Smaller ash particles are less common and build aggregates. Ash is deposited on the inlet DPF surface, the inlet channel walls, and in B100-DPF at the plugged ends of inlet channels. The presence of Fe–Cr–Ni fragments, down to tens of nanometers in size within the ash is attributed to engine wear. Pt particles (50–400 nm large) within the ash indicate that the diesel oxidation catalyst (DOC) upstream of the DPF shows aging effects. Radial cracks on the coating layer of the DOC confirm this assumption. The B100-DPF contains significantly less soot than B20 and B0. Based on the generally accepted view that soot reactivity correlates with the nanostructure of its primary particles, the length and curvature of graphene sheets from biofuel- and diesel-derived soot were measured and computed on the basis of HRTEM images. The results show that biofuel-derived soot can be more easily oxidized than diesel soot, not only during early formation but also during and after considerable particle growth. Differences in the graphene sheet separation distance, degree of crystalline order and size of primary soot particles between the two fuel types are in line with this inference.

  15. Surface Temperature Measurement Using Hematite Coating

    Science.gov (United States)

    Bencic, Timothy J. (Inventor)

    2015-01-01

    Systems and methods that are capable of measuring temperature via spectrophotometry principles are discussed herein. These systems and methods are based on the temperature dependence of the reflection spectrum of hematite. Light reflected from these sensors can be measured to determine a temperature, based on changes in the reflection spectrum discussed herein.

  16. CoFlame: A refined and validated numerical algorithm for modeling sooting laminar coflow diffusion flames

    Science.gov (United States)

    Eaves, Nick A.; Zhang, Qingan; Liu, Fengshan; Guo, Hongsheng; Dworkin, Seth B.; Thomson, Murray J.

    2016-10-01

    Mitigation of soot emissions from combustion devices is a global concern. For example, recent EURO 6 regulations for vehicles have placed stringent limits on soot emissions. In order to allow design engineers to achieve the goal of reduced soot emissions, they must have the tools to so. Due to the complex nature of soot formation, which includes growth and oxidation, detailed numerical models are required to gain fundamental insights into the mechanisms of soot formation. A detailed description of the CoFlame FORTRAN code which models sooting laminar coflow diffusion flames is given. The code solves axial and radial velocity, temperature, species conservation, and soot aggregate and primary particle number density equations. The sectional particle dynamics model includes nucleation, PAH condensation and HACA surface growth, surface oxidation, coagulation, fragmentation, particle diffusion, and thermophoresis. The code utilizes a distributed memory parallelization scheme with strip-domain decomposition. The public release of the CoFlame code, which has been refined in terms of coding structure, to the research community accompanies this paper. CoFlame is validated against experimental data for reattachment length in an axi-symmetric pipe with a sudden expansion, and ethylene-air and methane-air diffusion flames for multiple soot morphological parameters and gas-phase species. Finally, the parallel performance and computational costs of the code is investigated.

  17. Experimental Investigation of Nascent Soot Physical Properties and The Influence on Particle Morphology and Growth

    Science.gov (United States)

    Lieb, Sydnie Marie

    Soot released to the atmosphere is a dangerous pollutant for human health and the environment. Understanding the physical properties and surface properties of these particles is important to properly explaining the growth of soot particles in flames as well as their interactions with other particles and gases in the environment. Particles below 15 nm in diameter, nascent soot particles, dominate the early growth stages of soot formation; previously these particles were characterized as hard graphitic spheres. New evidence derived from the current dissertation work, to a large extent, challenges this prior characterization. This dissertation study begins by revisiting the use of atomic force microscope (AFM) as a tool to investigate the structural properties of nascent soot. The impact of tip artifacts, which are known to complicate measurements of features below 10 nm in diameter, are carefully considered so as to provide a concise interpretation of the morphology of nascent soot as seen by AFM. The results of the AFM morphology collaborate with earlier photo- and thermal-fragmentation particle mass spectrometry and Fourier transform infrared spectroscopy that nascent soot is not a graphitized carbon material and that they are not spherical. Furthermore, phase mode imaging is introduced as a method to investigate the physical properties of nascent soot particles in a greater detail and finer resolution. The helium ion microscope (HIM) has been identified as a useful technique for the imaging of nascent soot. Using this imaging method nascent soot particles were imaged with a high resolution that had not been obtained by prior techniques. The increased contrast provides a closer look at the nascent soot particles and further suggested that these particles are not as structurally homogeneous as previously thought. Geometric shape analysis was performed to characterize the particles in terms of sphericity, circularity, and fractal dimension. The geometric analysis

  18. Enhanced light absorption and scattering by carbon soot aerosol internally mixed with sulfuric acid.

    Science.gov (United States)

    Khalizov, Alexei F; Xue, Huaxin; Wang, Lin; Zheng, Jun; Zhang, Renyi

    2009-02-12

    Light absorption by carbon soot increases when the particles are internally mixed with nonabsorbing materials, leading to increased radiative forcing, but the magnitude of this enhancement is a subject of great uncertainty. We have performed laboratory experiments of the optical properties of fresh and internally mixed carbon soot aerosols with a known particle size, morphology, and the mixing state. Flame-generated soot aerosol is size-selected with a double-differential mobility analyzer (DMA) setup to eliminate multiply charged particle modes and then exposed to gaseous sulfuric acid (10(9)-10(10) molecule cm(-3)) and water vapor (5-80% relative humidity, RH). Light extinction and scattering by fresh and internally mixed soot aerosol are measured at 532 nm wavelength using a cavity ring-down spectrometer and an integrating nephelometer, respectively, and the absorption is derived as the difference between extinction and scattering. The optical properties of fresh soot are independent of RH, whereas soot internally mixed with sulfuric acid exhibits significant enhancement in light absorption and scattering, increasing with the mass fraction of sulfuric acid coating and relative humidity. For soot particles with an initial mobility diameter of 320 nm and a 40% H(2)SO(4) mass coating fraction, absorption and scattering are increased by 1.4- and 13-fold at 80% RH, respectively. Also, the single scattering albedo of soot aerosol increases from 0.1 to 0.5 after coating and humidification. Additional measurements with soot particles that are first coated with sulfuric acid and then heated to remove the coating show that both scattering and absorption are enhanced by irreversible restructuring of soot aggregates to more compact globules. Depending on the initial size and density of soot aggregates, restructuring acts to increase or decrease the absorption cross-section, but the combination of restructuring and encapsulation always results in an increased absorption for

  19. Fast Soot Aging and Pronounced Diurnal Evolution of Size-dependent Soot Mixing State in the Megacity Beijing

    Science.gov (United States)

    Cheng, Y.; Su, H.; Wiedensohler, A.; Berghof, M.; Wehner, B.; Achtert, P.; Nowak, A.; Zhang, Y.; Shao, M.; Zhu, T.; Zeng, L.; Carmichael, G. R.

    2009-12-01

    The mixing state of soot has great implication in its optical and hygroscopic properties, and hence on its direct/indirect radiative effects. Up to date, understanding about the mechanism of the soot mixing state evolution is still poor and only a few techniques are able to measure the soot mixing state with a high-time and -size resolution. During the CAREBEIJING-2006 (Aug-Sep), a Volatility Tandem Differential Mobility Analyzer was applied to measure the soot mixture in a particle size range of 30 to 320 nm at a regional polluted site in the area of megacity Beijing [Wehner et al., 2009]. The number fraction of externally mixed soot (Fex) varied from 5 to 60% and showed a clear size-dependent diurnal variation. After a peak in the morning, Fex started decreasing and reached a minimum at around noon. Smaller particles reached the minimum earlier than the larger ones, i.e., Fex of 30 nm particles reached its minimum at 8:00-9:00 while that of 320 nm reached the minimum at 13:00-14:00. The different Fex variations among different sizes reflect a combined effect of size-dependent condensable vapor supersaturations and particle growth rates. Fast evolution of soot mixing states was found. During a typical day with new particle formation followed by continuously condensational growth [Wiedensohler et al., 2009], the coating enhancement in light absorption (σap) and scattering of coated soot can simultaneously reach up to a factor of 8-10 within several hours. It was contributed not only by the increasing thickness of coating shell but also by the fast transition from externally mixed soots to coated ones [Cheng et al., 2009]. The number fraction of coated soot (Fcoat) is strongly correlated with the photochemical aging process (e.g., OH time integrals (TOH) calculated by the ratio of m+p xylnene to ethylbenzen). Similar phenomena were found by Moteki et al. [2007] and Shiraiwa et al. [2007]. Interestingly, an “exponential decay” of the external mixed to coated

  20. Temperature measurement by neutron resonance radiography

    International Nuclear Information System (INIS)

    Mayers, J.; Baciocco, G.; Hannon, A.C.

    1988-03-01

    We present a new data analysis technique for obtaining temperatures from neutron resonance radiography measurements. The technique is applied to measurements on tantalum and rhenium foils, a high temperature engineering alloy and a model catalytic system. Temperatures have been obtained to an accuracy of better than ± 1 0 C in the temperature range 21 0 C to 600 0 C. The results are in good agreement with theoretical simulations. (author)

  1. Development of a 2D temperature measurement technique for combustion diagnostics using 2-line atomic fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Johan

    2001-01-01

    The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical Sl engine using isooctane as fuel. The wide temperature sensitivity, 700 - 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH

  2. Temperature measurements in cavitation bubbles

    Science.gov (United States)

    Coutier-Delgosha, Olivier

    2016-11-01

    Cavitation is usually a nearly isothermal process in the liquid phase, but in some specific flow conditions like hot water or cryogenic fluids, significant temperature variations are detected. In addition, a large temperature increase happens inside the cavitation bubbles at the very end of their collapse, due to the fast compression of the gas at the bubble core, which is almost adiabatic. This process is of primary interest in various biomedical and pharmaceutical applications, where the mechanisms of bubble collapse plays a major role. To investigate the amplitude and the spatial distribution of these temperature variations inside and outside the cavitation bubbles, a system based on cold wires has been developed. They have been tested in a configuration of a single bubble obtained by submitting a small air bubble to a large amplitude pressure wave. Some promising results have been obtained after the initial validation tests. This work is funded by the Office of Naval Research Global under Grant N62909-16-1-2116, Dr. Salahuddin Ahmed & Ki-Han Kim program managers.

  3. Field of Temperature Measurement by Virtual Instrumentation

    Directory of Open Access Journals (Sweden)

    Libor HARGAŠ

    2009-01-01

    Full Text Available This paper introduces about temperature determination for given dot of picture through image analysis. Heat transfer is the transition of thermal energy from a heated item to a cooler item. Main method of measurement of temperature in image is Pattern Matching, color scale detection and model detection. We can measure temperature dependency at time for selected point of thermo vision images. This measurement gives idea about the heat transfer at time dependences.

  4. Role of iron oxide catalysts in selective catalytic reduction of NOx and soot from vehicular emission

    International Nuclear Information System (INIS)

    Anjuman, S.; Tahira, S.; Hizbullah, K.; Hizbullah, K.

    2011-01-01

    This study deals with Iron containing catalysts i.e Iron oxide Fe/sub 2/O/sub 3/) Iron potassium oxide Fe/sub 1.9/K/sub 0.1/O/sub 3/, copper iron oxide Cu/sub 0.9/K/sub 0.1/, Fe/sub 2/O/sub 3/, nickel iron oxide Ni Fe/sub 2/O/sub 4/, and Nickel potassium iron oxide Ni/sub 0.95/K/sub 0.05/ Fe/sub 2/O/sub 4/ catalyst were synthesized by using PVA technique. By X-ray Diffraction technique these catalysts were characterized to ensure the formation of crystalline structure. Energy Dispersive X-rays analysis (EDX) was used for the confirmation of presence of different metals and Scanning Electron Microscopy (SEM) for Surface Morphology. Then the catalytic investigations of the prepared catalyst were carried out for their activity measurement toward simultaneous conversion of NOx and Soot from an engine exhaust. Some Iron containing oxide catalysts were partially modified by alkali metal potassium and were used for NOx -Soot reaction in a model exhaust gas. Fe/sub 1.9 K /sub 0.1/O/sub 3/ show high catalytic performance for N/sub 2/ formation in the prepared catalyst. Further studies have shown that Fe/sub 1.9/ K/sub 0.1/ O/sub 3/ was deactivated in a substantial way after about 20 Temperature. Temperature Programmed Reaction (TPR) experiments due to agglomeration of the promoter potassium. Experiments carried out over the aged Fe/sub 1.9/K/sub 0.1/O/sub 3/ catalyst have shown that NOx-soot reaction was suppressed at higher oxygen concentration, since O/sub 2/-soot conversion was kindly favored. More over nitrite species formed at the catalyst surface might play an important role in NOx-soot conversion. (author)

  5. Temperature standards, what and where: resources for effective temperature measurements

    International Nuclear Information System (INIS)

    Johnston, W.W. Jr.

    1982-01-01

    Many standards have been published to describe devices, methods, and other topics. How they are developed and by whom are briefly described, and an attempt is made to extract most of those relating to temperature measurements. A directory of temperature standards and their sources is provided

  6. Camphor soot: a tunable light emitter

    Science.gov (United States)

    Swapna, M. S.; Saritha Devi, H. V.; Sankararaman, S.

    2018-01-01

    The work in this paper is the first report on the green synthesis of the blue light emitter from waxy, flammable solid collected from Cinnamomum camphora by controlled combustion for photonic applications. Analysis with field emission scanning electron microscope and high-resolution transmission electron microscope provides the morphology, whereas the thermogravimetric analysis gives the thermal stability of the soot. The optical and structural characterizations are done by recording UV-Visible, Photoluminescent, and Raman Spectrum. The CIE plot and the power spectrum of the sample show a blue emission at an excitation of 350 nm at room temperature with a quantum yield of 46.15%. The dependence of luminescent behavior on temperature and excitation wavelength reveals that the material is a tunable blue emitter. This green synthesis of the blue light emitter is highly significant, when the world is in search of a simple, phosphor-free, non-toxic, cost-effective material with good quantum efficiency.

  7. A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN)

    KAUST Repository

    Skeen, Scott A.

    2016-04-05

    The 4th Workshop of the Engine Combustion Network (ECN) was held September 5-6, 2015 in Kyoto, Japan. This manuscript presents a summary of the progress in experiments and modeling among ECN contributors leading to a better understanding of soot formation under the ECN “Spray A” configuration and some parametric variants. Relevant published and unpublished work from prior ECN workshops is reviewed. Experiments measuring soot particle size and morphology, soot volume fraction (fv), and transient soot mass have been conducted at various international institutions providing target data for improvements to computational models. Multiple modeling contributions using both the Reynolds Averaged Navier-Stokes (RANS) Equations approach and the Large-Eddy Simulation (LES) approach have been submitted. Among these, various chemical mechanisms, soot models, and turbulence-chemistry interaction (TCI) methodologies have been considered.

  8. Quantitative shearography in axisymmetric gas temperature measurements

    Science.gov (United States)

    VanDerWege, Brad A.; O'Brien, Christopher J.; Hochgreb, Simone

    1999-06-01

    This paper describes the use of shearing interferometry (shearography) for the quantitative measurement of gas temperatures in axisymmetric systems in which vibration and shock are substantial, and measurement time is limited. The setup and principle of operation of the interferometer are described, as well as Fourier-transform-based fringe pattern analysis, Abel transform, and sensitivity of the phase lead to temperature calculation. A helium jet and a Bunsen burner flame are shown as verification of the diagnostic. The accuracy of the measured temperature profile is shown to be limited by the Abel transform and is critically dependent on the reference temperature used.

  9. Minimizing noise-temperature measurement errors

    Science.gov (United States)

    Stelzried, C. T.

    1992-01-01

    An analysis of noise-temperature measurement errors of low-noise amplifiers was performed. Results of this analysis can be used to optimize measurement schemes for minimum errors. For the cases evaluated, the effective noise temperature (Te) of a Ka-band maser can be measured most accurately by switching between an ambient and a 2-K cooled load without an isolation attenuator. A measurement accuracy of 0.3 K was obtained for this example.

  10. Temperature Sensitive Particle for Velocity and Temperature Measurement.

    Science.gov (United States)

    Someya, Satoshi; Okamoto, Koji; Iida, Masao

    2007-11-01

    Phosphorescence and fluorescence are often applied to measure the temperature and the concentration of oxygen. The intensity and the lifetime of phosphor depend on the temperature and the oxygen concentration, due to the quenching effect of the phosphor. The present study clarified the effects of temperature on the lifetime of phosphorescence of Porphyrins, Ru(bpy)3^2+ and the europium complex. The phosphorescence lifetime of oil solution / water solution / painted wall were measured with changing temperature and oxygen concentration. In addition, the optical property of the small particles incorporated with the europium complex was investigated in the oil/water. The lifetime was strongly affected by temperature. Then, the temperature sensitive particle (TSParticle) with metal complex was applied to measure temperature in Silicone oil (10cSt) two-dimensionally. Present study is the result of ?High speed three-dimensional direct measurement technology development for the evaluation of heat flux and flow of liquid metal? entrusted to the University of Tokyo by the Ministry of Education, Culture, Sports, Science and Technology of Japan(MEXT).

  11. Uptake of HNO3 on aviation kerosene and aircraft engine soot: influences of H2O or/and H2SO4.

    Science.gov (United States)

    Loukhovitskaya, Ekaterina E; Talukdar, Ranajit K; Ravishankara, A R

    2013-06-13

    The uptake of HNO3 on aviation kerosene soot (TC-1 soot) was studied in the absence and presence of water vapor at 295 and 243 K. The influence of H2SO4 coating of the TC-1 soot surface on HNO3 uptake was also investigated. Only reversible uptake of HNO3 was observed. HONO and NO2, potential products of reactive uptake of HNO3, were not observed under any conditions studied here. The uptake of nitric acid increased slightly with relative humidity (RH). Coating of the TC-1 soot surface with sulfuric acid decreased the uptake of HNO3 and did not lead to displacement of H2SO4 from the soot surface. A limited set of measurements was carried out on soot generated by aircraft engine combustor (E-soot) with results similar to those on TC-1 soot. The influence of water on HNO3 uptake on E-soot appeared to be more pronounced than on TC-1 soot. Our results suggest that HNO3 loss in the upper troposphere due to soot is not significant except perhaps in aircraft exhaust plumes. Our results also suggest that HNO3 is not converted to either NO2 or HONO upon its uptake on soot in the atmosphere.

  12. Fundamental insight in soot oxidation over a Ag/Co3O4 catalyst by means of Environmental TEM

    DEFF Research Database (Denmark)

    Gardini, Diego; Christiansen, J. M.; Jensen, Anker Degn

    A novel Ag/Co3O4 catalyst for low-temperature soot oxidation has been studied by means of environmental TEM in order to get fundamental insight in the oxidation mechanism. Soot particles generated in diesel engines are responsible for respiratory diseases, lung cancer and affect the climate both....... Catalytic tests of the novel Ag/Co3O4 system carried out in a flow reactor show high conversion efficiencies. The temperature dependence of the soot oxidation rate for this new system cannot be directly described in terms of the activity of the single Ag and Co3O4 components, but is strongly dependent...... on preparation method, degree of contact with the soot and temperature range. In order to fully understand the role of the single constituents and the influence of different operating conditions in the overall catalytic activity, flow reactor experiments have been coupled with in situ soot oxidation...

  13. Designing an accurate system for temperature measurements

    Directory of Open Access Journals (Sweden)

    Kochan Orest

    2017-01-01

    Full Text Available The method of compensation of changes in temperature field along the legs of inhomogeneous thermocouple, which measures a temperature of an object, is considered in this paper. This compensation is achieved by stabilization of the temperature field along the thermocouple. Such stabilization does not allow the error due to acquired thermoelectric inhomogeneity to manifest itself. There is also proposed the design of the furnace to stabilize temperature field along the legs of the thermocouple which measures the temperature of an object. This furnace is not integrated with the thermocouple mentioned above, therefore it is possible to replace this thermocouple with a new one when it get its legs considerably inhomogeneous.. There is designed the two loop measuring system with the ability of error correction which can use simultaneously a usual thermocouple as well as a thermocouple with controlled profile of temperature field. The latter can be used as a reference sensor for the former.

  14. Estimation of complete temperature fields from measured temperatures

    International Nuclear Information System (INIS)

    Clegg, S.T.; Roemer, R.B.

    1984-01-01

    In hyperthermia treatments, it is desirable to be able to predict complete tissue temperature fields from sampled temperatures taken at a few locations. This is a difficult problem in hyperthermia treatments since the tissue blood perfusion is unknown. An initial attempt to do this automatically using unconstrained optimization techniques to minimize the differences between steady state temperatures measured during a treatment and temperatures (at the same locations) predicted from treatment simulations has been previously reported. A second technique using transient temperatures following a step decrease in power has been developed. This technique, which appears to be able to better predict complete temperature fields is presented and both it and the steady state technique are applied to data from both simulated and experimental hyperthermia treatments. The results of applying the two techniques are compared for one-dimensional situations. One particularly important problem which the transient technique can solve (and the steady state technique does not seem to be able to do as well) is that of predicting the complete temperature field in situations where the true maximum and/or minimum temperatures present are not measured by the available instrumentation

  15. [Temperature Measurement with Bluetooth under Android Platform].

    Science.gov (United States)

    Wang, Shuai; Shen, Hao; Luo, Changze

    2015-03-01

    To realize the real-time transmission of temperature data and display using the platform of intelligent mobile phone and bluetooth. Application of Arduino Uno R3 in temperature data acquisition of digital temperature sensor DS18B20 acquisition, through the HC-05 bluetooth transmits the data to the intelligent smart phone Android system, realizes transmission of temperature data. Using Java language to write applications program under Android development environment, can achieve real-time temperature data display, storage and drawing temperature fluctuations drawn graphics. Temperature sensor is experimentally tested to meet the body temperature measurement precision and accuracy. This paper can provide a reference for other smart phone mobile medical product development.

  16. Nanoparticle production by UV irradiation of combustion generated soot particles

    International Nuclear Information System (INIS)

    Stipe, Christopher B.; Choi, Jong Hyun; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

    2004-01-01

    Laser ablation of surfaces normally produce high temperature plasmas that are difficult to control. By irradiating small particles in the gas phase, we can better control the size and concentration of the resulting particles when different materials are photofragmented. Here, we irradiate soot with 193 nm light from an ArF excimer laser. Irradiating the original agglomerated particles at fluences ranging from 0.07 to 0.26 J/cm 2 with repetition rates of 20 and 100 Hz produces a large number of small, unagglomerated particles, and a smaller number of spherical agglomerated particles. Mean particle diameters from 20 to 50 nm are produced from soot originally having a mean electric mobility diameter of 265nm. We use a non-dimensional parameter, called the photon/atom ratio (PAR), to aid in understanding the photofragmentation process. This parameter is the ratio of the number of photons striking the soot particles to the number of the carbon atoms contained in the soot particles, and is a better metric than the laser fluence for analyzing laser-particle interactions. These results suggest that UV photofragmentation can be effective in controlling particle size and morphology, and can be a useful diagnostic for studying elements of the laser ablation process

  17. Effects of Structure and Hydrodynamics on the Sooting Behavior of Spherical Microgravity Diffusion Flames

    Science.gov (United States)

    Sunderland, P. B.; Axelbaum, R. L.; Urban, D. L.

    1999-01-01

    Recent experimental, numerical and analytical work has shown that the stoichiometric mixture fraction (Z(sub st)) can have a profound effect on soot formation in diffusion flames. These findings were obtained at constant flame temperature (T(sub ad)), employing the approach described in Du and Axelbaum (1995, 1996). For example, a fuel mixture containing 1 mole of ethylene and 11.28 moles of nitrogen burning in pure oxygen ((Z(sub st)) = 0.78) has the same adiabatic flame temperature (2370 K) as that of pure ethylene burning in air ((Z(sub st)) = 0.064). An important finding of these works was that at sufficiently high (Z(sub st)), flames remain blue as strain rate approaches zero in counterflow flames, or as flame height and residence time approach infinity in coflowing flames. Lin and Faeth (1996a) coined the term permanently blue to describe such flames. Two theories have been proposed to explain the appearance of permanently-blue flames at high (Z(sub st)). They are based on (1) hydrodynamics and (2) flame structure. Previous experimental studies in normal gravity are not definitive as to which, if either, mechanism is dominant because both hydrodynamics and structure suppress soot formation at high (Z(sub st)) in coflowing and counterflowing diffusion flames. In counterflow flames with (Z(sub st)) 0.5, convection at the flame is toward the oxidizer, thus enhancing soot oxidization. Thus, in counterflow flames, hydrodynamics causes soot to be convected towards the oxidizer at high (Z(sub st)) which suppresses soot formation. Axelbaum and co-workers maintain that while the direction of convection can impact soot growth and oxidation, these processes alone cannot cause permanently-blue flames. Soot growth and oxidation are dependent on the existence of soot particles and the presence of soot is invariably accompanied by yellow luminosity. Soot-particle inception, on the other hand, arises from gas-phase reactions and its dependence on flow direction is weak

  18. Modelling maximum adsorption capacities of soot and soot-like materials for PAHs and PCBs

    NARCIS (Netherlands)

    Noort, van P.C.M.; Jonker, M.T.O.; Koelmans, A.A.

    2004-01-01

    Recent studies have shown that not partitioning but adsorption is the main mechanism for sorption of hydrophobic organic compounds to soot and soot-like materials. For compounds that adsorb by van der Waals forces only, variation in soot-water distribution coefficients will result from differences

  19. Asymptotic analysis soot model and experiment for a directed injection engine

    Science.gov (United States)

    Liu, Yongfeng; Pei, Pucheng; Xiong, Qinghui; Lu, Yong

    2012-09-01

    The existing soot models are either too complex and can not be applied to the internal combustion engine, or too simple to make calculation errors. Exploring the soot model becomes the pursuit of the goal of many researchers within the error range in the current computer speed. On the basis of the latest experimental results, TP (temperature phases) model is presented as a new soot model to carry out optimization calculation for a high-pressure common rail diesel engine. Temperature and excess air factor are the most important two parameters in this model. When zone temperature T0.6, only the soot precursors—polycyclic aromatic hydrocarbons(PAH) is created and there is no soot emission. When zone temperature T ⩾ 1 500 K and excess air factor Φinjection time, variation of rail pressure and variation of speed among TP models. The experimental results indicate that the TP model can carry out optimization and computational fluid dynamics can be a tool to calculate for a high-pressure common rail directed injection diesel engine. The TP model result is closer than the use of the original KIVA-3V results of soot model accuracy by about 50% and TP model gives a new method for engine researchers.

  20. Optimized Heating Rate and Soot-catalyst Ratio for Soot Oxidation over MoO3 Catalyst

    Directory of Open Access Journals (Sweden)

    Congwei Mei

    2017-10-01

    Full Text Available MoO3 is now utilized as a promising catalyst due to its high activity and favorable mobility at low temperature. Its spectral data and surface microstructures were characterized by Fourier transform infrared spectra (FT-IR and Field emission scanning electron microscope (FESEM. Thermo-analysis of the carbon black was performed over nano-MoO3 catalyst in a thermogravimetric analyzer (TGA at various heating rates and soot-catalyst ratios. Through the analysis of kinetic parameters, we found that the heat transfer effect and diffusion effect can be removed by setting lower heating rates and soot-catalyst ratios. Therefore, a strategy for selecting proper thermogravimetric parameters were established, which can contribute to the better understanding of thermo-analytical process. Copyright © 2017 BCREC Group. All rights reserved Received: 4th December 2016; Revised: 13rd June 2017; Accepted: 9th April 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Mei, C., Mei, D., Yue, S, Chen, Z., Yuan, Y. (2017. Optimized Heating Rate and Soot-catalyst Ratio for Soot Oxidation over MoO3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3: 408-414 (doi:10.9767/bcrec.12.3.845.408-414

  1. Analysis of turbulence and surface growth models on the estimation of soot level in ethylene non-premixed flames

    Science.gov (United States)

    Yunardi, Y.; Munawar, Edi; Rinaldi, Wahyu; Razali, Asbar; Iskandar, Elwina; Fairweather, M.

    2018-02-01

    Soot prediction in a combustion system has become a subject of attention, as many factors influence its accuracy. An accurate temperature prediction will likely yield better soot predictions, since the inception, growth and destruction of the soot are affected by the temperature. This paper reported the study on the influences of turbulence closure and surface growth models on the prediction of soot levels in turbulent flames. The results demonstrated that a substantial distinction was observed in terms of temperature predictions derived using the k-ɛ and the Reynolds stress models, for the two ethylene flames studied here amongst the four types of surface growth rate model investigated, the assumption of the soot surface growth rate proportional to the particle number density, but independent on the surface area of soot particles, f ( A s ) = ρ N s , yields in closest agreement with the radial data. Without any adjustment to the constants in the surface growth term, other approaches where the surface growth directly proportional to the surface area and square root of surface area, f ( A s ) = A s and f ( A s ) = √ A s , result in an under- prediction of soot volume fraction. These results suggest that predictions of soot volume fraction are sensitive to the modelling of surface growth.

  2. Dynamic temperature measurements with embedded optical sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H.,; Seagle, Christopher T; Ao, Tommy

    2013-10-01

    This report summarizes LDRD project number 151365, \\Dynamic Temperature Measurements with Embedded Optical Sensors". The purpose of this project was to develop an optical sensor capable of detecting modest temperature states (<1000 K) with nanosecond time resolution, a recurring diagnostic need in dynamic compression experiments at the Sandia Z machine. Gold sensors were selected because the visible re ectance spectrum of gold varies strongly with temperature. A variety of static and dynamic measurements were performed to assess re ectance changes at di erent temperatures and pressures. Using a minimal optical model for gold, a plausible connection between static calibrations and dynamic measurements was found. With re nements to the model and diagnostic upgrades, embedded gold sensors seem capable of detecting minor (<50 K) temperature changes under dynamic compression.

  3. Small particles big effect? - Investigating ice nucleation abilities of soot particles

    Science.gov (United States)

    Mahrt, Fabian; David, Robert O.; Lohmann, Ulrike; Stopford, Chris; Wu, Zhijun; Kanji, Zamin A.

    2017-04-01

    Atmospheric soot particles are primary particles produced by incomplete combustion of biomass and/or fossil fuels. Thus soot mainly originates from anthropogenic emissions, stemming from combustion related processes in transport vehicles, industrial and residential uses. Such soot particles are generally complex mixtures of black carbon (BC) and organic matter (OM) (Bond et al., 2013; Petzold et al., 2013), depending on the sources and the interaction of the primary particles with other atmospheric matter and/or gases BC absorbs solar radiation having a warming effect on global climate. It can also act as a heterogeneous ice nucleating particle (INP) and thus impact cloud-radiation interactions, potentially cooling the climate (Lohmann, 2002). Previous studies, however, have shown conflicting results concerning the ice nucleation ability of soot, limiting the ability to predict its effects on Earth's radiation budget. Here we present a laboratory study where we systematically investigate the ice nucleation behavior of different soot particles. Commercial soot samples are used, including an amorphous, industrial carbon frequently used in coatings and coloring (FW 200, Orion Engineered Carbons) and a fullerene soot (572497 ALDRICH), e.g. used as catalyst. In addition, we use soot generated from a propane flame Combustion Aerosol Standard Generator (miniCAST, JING AG), as a proxy for atmospheric soot particles. The ice nucleation ability of these soot types is tested on size-selected particles for a wide temperature range from 253 K to 218 K, using the Horizontal Ice Nucleation Chamber (HINC), a Continuous Flow Diffusion Chamber (CFDC) (Kanji and Abbatt, 2009). Ice nucleation results from these soot surrogates will be compared to chemically more complex real world samples, collected on filters. Filters will be collected during the 2016/2017 winter haze periods in Beijing, China and represent atmospheric soot particles with sources from both industrial and residential

  4. Emission, Structure and Optical Properties of Overfire Soot from Buoyant Turbulent Diffusion Flames

    Science.gov (United States)

    Koylu, Umit Ozgur

    The present study investigated soot and carbon monoxide emissions, and evaluated the optical properties of soot, in the overfire region of buoyant turbulent diffusion flames burning in still air. Soot and carbon monoxide emissions, and the corresponding correlation between these emissions, were studied experimentally. The optical properties of soot were investigated both experimentally and theoretically. The experiments involved gas (acetylene, propylene, ethylene, propane, methane) and liquid (toluene, benzene, n-heptane, iso-propanol, ethanol, methanol) fuels. The investigation was limited to the fuel-lean (overfire) region of buoyant turbulent diffusion flames burning in still air. Measurements included flame heights, characteristic flame residence times, carbon monoxide and soot concentrations, mixture fractions, ex-situ soot structure parameters (primary particle sizes, number of primary particles in aggregates, fractal dimensions), and in-situ optical cross sections (differential scattering, total scattering, and absorption) of soot in the overfire region of buoyant turbulent diffusion flames, emphasizing conditions in the long residence time regime where these properties are independent of position in the overfire region and flame residence time. The predictions of optical cross sections for polydisperse aggregates were based on Rayleigh-Debye-Gans theory for fractal aggregates; the predictions of this theory were evaluated by combining the TEM structure and the light scattering/extinction measurements. Carbon monoxide concentrations and mixture fractions were correlated in the overfire region of gas- and liquid -fueled turbulent diffusion flames. Soot volume fraction state relationships were observed for liquid fuels, supporting earlier observations for gas fuels. A strong correlation between carbon monoxide and soot concentrations was established in the fuel-lean region of both gas- and liquid-fueled turbulent diffusion flames. The structure and emission

  5. Measuring nanowire thermal conductivity at high temperatures

    Science.gov (United States)

    Wang, Xiaomeng; Yang, Juekuan; Xiong, Yucheng; Huang, Baoling; Xu, Terry T.; Li, Deyu; Xu, Dongyan

    2018-02-01

    This work extends the micro-thermal-bridge method for thermal conductivity measurements of nanowires to high temperatures. The thermal-bridge method, based on a microfabricated device with two side-by-side suspended membranes with integrated platinum resistance heaters/thermometers, has been used to determine thermal conductivity of various nanowires/nanotubes/nanoribbons at relatively low temperatures. However, to date, thermal conductivity characterization of nanowires at temperatures above 600 K has seldom been reported presumably due to several technical difficulties including the instability of the microfabricated thermometers, radiation heat loss, and the effect of the background conductance on the measurement. Here we report on our attempt to address the aforementioned challenges and demonstrate thermal conductivity measurement of boron nanoribbons up to 740 K. To eliminate high temperature resistance instability, the device is first annealed at 1023 K for 5 min in an argon atmosphere. Two radiation shields are installed in the measurement chamber to minimize radiation heat loss from the measurement device to the surroundings; and the temperature of the device at each set point is calibrated by an additional thermocouple directly mounted on the chip carrier. The effect of the background conductance is eliminated by adopting a differential measurement scheme. With all these modifications, we successfully measured the thermal conductivity of boron nanoribbons over a wide temperature range from 27 K to 740 K. The measured thermal conductivity increases monotonically with temperature and reaches a plateau of ~2.5 W m‑1 K‑1 at approximately 400 K, with no clear signature of Umklapp scattering observed in the whole measurement temperature range.

  6. Electron Density and Temperature Measurements, and Abundance ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Using spectra obtained from the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory), we investigate the height dependence of electron density, temperature and abundance anomalies in the solar atmosphere.

  7. General temperature field measurement by digital holography

    Czech Academy of Sciences Publication Activity Database

    Doleček, Roman; Psota, Pavel; Lédl, Vít; Vít, Tomáš; Václavík, Jan; Kopecký, V.

    2013-01-01

    Roč. 52, č. 1 (2013), A319-A325 ISSN 1559-128X Institutional support: RVO:61389021 Keywords : digital holography * temperature field measurement * tomography Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.649, year: 2013

  8. Noise thermometry - a new temperature measuring method

    International Nuclear Information System (INIS)

    Brixy, H.; Hecker, R.; Rittinghaus, K.F.

    1975-01-01

    The thermal Johnson-Niquist noise is the basis of noise thermometry. This temperature measuring method is, e.g., of interest insofar as the noise thermometer gives absolute values as a primary thermometer and is in principle extensively independent of environmental influences and material properties. The resistance values of the measuring probe are about 10 Ohm to a few kOhm. The demands of electronics are high, the self-noise of the measuring apparatus must be as small as possible; a comparative measuring method is advantageous. 1 to 2,500 K are given as a possible temperature range. An accuracy of 0.1% could be achieved in laboratory measurements. Temperature measurements to be used in operation in a few nuclear reactors are mentioned. (HP/LH) [de

  9. Damköhler number effects on soot formation and growth in turbulent nonpremixed flames

    KAUST Repository

    Attili, Antonio

    2015-01-01

    The effect of Damköhler number on turbulent nonpremixed sooting flames is investigated via large scale direct numerical simulation in three-dimensional n-heptane/air jet flames at a jet Reynolds number of 15,000 and at three different Damköhler numbers. A reduced chemical mechanism, which includes the soot precursor naphthalene, and a high-order method of moments are employed. At the highest Damköhler number, local extinction is negligible, while flames holes are observed in the two lowest Damköhler number cases. Compared to temperature and other species controlled by fuel oxidation chemistry, naphthalene is found to be affected more significantly by the Damköhler number. Consequently, the overall soot mass fraction decreases by more than one order of magnitude for a fourfold decrease of the Damköhler number. On the contrary, the overall number density of soot particles is approximately the same, but its distribution in mixture fraction space is different in the three cases. The total soot mass growth rate is found to be proportional to the Damköhler number. In the two lowest Da number cases, soot leakage across the flame is observed. Leveraging Lagrangian statistics, it is concluded that soot leakage is due to patches of soot that cross the stoichiometric surface through flame holes. These results show the leading order effects of turbulent mixing in controlling the dynamics of soot in turbulent flames. © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  10. Wideband filter radiometers for blackbody temperature measurements

    Science.gov (United States)

    Boivin, L. P.; Bamber, C.; Gaertner, A. A.; Gerson, R. K.; Woods, D. J.; Woolliams, E. R.

    2010-10-01

    The use of high-temperature blackbody (HTBB) radiators to realize primary spectral irradiance scales requires that the operating temperature of the HTBB be accurately determined. We have developed five filter radiometers (FRs) to measure the temperature of the National Research Council of Canada's HTBB. The FRs are designed to minimize sensitivity to ambient temperature fluctuations. They incorporate air-spaced colored glass filters and a Si photodiode detector that are housed in a cell whose temperature is controlled to ±0.1°C by means of annular thermoelectric elements at the front and rear of the cell. These wideband filter radiometers operate in four different wavelength bands. The spectral responsivity measurements were performed in an underfill geometry for a power-mode calibration that is traceable to NRC's cryogenic radiometer. The spectral temperature sensitivity of each of these FRs has been measured. The apertures for these FRs were cold-formed by swaging machine-cut apertures onto precision dowel pins. A description of the filter radiometer design, fabrication and testing, together with a detailed uncertainty analysis, is presented. We derive the equations that relate the spectral irradiance measured by the FRs to the spectral radiance and temperature of the HTBB, and deal specifically with the change of index of refraction over the path of the radiation from the interior of the HTBB to the FRs. We believe these equations are more accurate than recently published derivations. Our measurements of the operating temperature of our HTBB working at temperatures near 2500 K, 2700 K and 2900 K, together with measurements using a pyrometer, show agreement between the five filter radiometers and with the pyrometer to within the estimated uncertainties.

  11. Simulation of soot size distribution in an ethylene counterflow flame

    KAUST Repository

    Zhou, Kun

    2014-01-06

    Soot, an aggregate of carbonaceous particles produced during the rich combustion of fossil fuels, is an undesirable pollutant and health hazard. Soot evolution involves various dynamic processes: nucleation soot formation from polycyclic aromatic hydrocarbons (PAHs) condensation PAHs condensing on soot particle surface surface processes hydrogen-abstraction-C2H2-addition, oxidation coagulation two soot particles coagulating to form a bigger particle This simulation work investigates soot size distribution and morphology in an ethylene counterflow flame, using i). Chemkin with a method of moments to deal with the coupling between vapor consumption and soot formation; ii). Monte Carlo simulation of soot dynamics.

  12. Laser-Induced Emissions Sensor for Soot Mass in Rocket Plumes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A method is proposed to measure soot mass concentration non-intrusively from a distance in a rocket engine exhaust stream during ground tests using laser-induced...

  13. Laser-Induced Emissions Sensor for Soot Mass in Rocket Plumes, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A method is proposed to measure soot mass concentration non-intrusively from a distance in a rocket engine exhaust stream during ground tests using laser-induced...

  14. Fragmentation and bond strength of airborne diesel soot agglomerates

    Directory of Open Access Journals (Sweden)

    Messerer Armin

    2008-06-01

    Full Text Available Abstract Background The potential of diesel soot aerosol particles to break up into smaller units under mechanical stress was investigated by a direct impaction technique which measures the degree of fragmentation of individual agglomerates vs. impact energy. Diesel aerosol was generated by an idling diesel engine used for passenger vehicles. Both the aerosol emitted directly and aerosol that had undergone additional growth by Brownian coagulation ("aging" was investigated. Optionally a thermo-desoption technique at 280°C was used to remove all high-volatility and the majority of low-volatility HC adsorbates from the aerosol before aging. Results It was found that the primary soot agglomerates emitted directly from the engine could not be fragmented at all. Soot agglomerates permitted to grow additionally by Brownian coagulation of the primary emitted particles could be fragmented to a maximum of 75% and 60% respectively, depending on whether adsorbates were removed from their surface prior to aging or not. At most, these aged agglomerates could be broken down to roughly the size of the agglomerates from the primary emission. The energy required for a 50% fragmentation probability of all bonds within an agglomerate was reduced by roughly a factor of 2 when aging "dry" agglomerates. Average bond energies derived from the data were 0.52*10-16 and 1.2*10-16 J, respectively. This is about 2 orders of magnitude higher than estimates for pure van-der-Waals agglomerates, but agrees quite well with other observations. Conclusion Although direct conclusions regarding the behavior of inhaled diesel aerosol in contact with body fluids cannot be drawn from such measurements, the results imply that highly agglomerated soot aerosol particles are unlikely to break up into units smaller than roughly the size distribution emitted as tail pipe soot.

  15. Fragmentation and bond strength of airborne diesel soot agglomerates

    Science.gov (United States)

    Rothenbacher, Sonja; Messerer, Armin; Kasper, Gerhard

    2008-01-01

    Background The potential of diesel soot aerosol particles to break up into smaller units under mechanical stress was investigated by a direct impaction technique which measures the degree of fragmentation of individual agglomerates vs. impact energy. Diesel aerosol was generated by an idling diesel engine used for passenger vehicles. Both the aerosol emitted directly and aerosol that had undergone additional growth by Brownian coagulation ("aging") was investigated. Optionally a thermo-desoption technique at 280°C was used to remove all high-volatility and the majority of low-volatility HC adsorbates from the aerosol before aging. Results It was found that the primary soot agglomerates emitted directly from the engine could not be fragmented at all. Soot agglomerates permitted to grow additionally by Brownian coagulation of the primary emitted particles could be fragmented to a maximum of 75% and 60% respectively, depending on whether adsorbates were removed from their surface prior to aging or not. At most, these aged agglomerates could be broken down to roughly the size of the agglomerates from the primary emission. The energy required for a 50% fragmentation probability of all bonds within an agglomerate was reduced by roughly a factor of 2 when aging "dry" agglomerates. Average bond energies derived from the data were 0.52*10-16 and 1.2*10-16 J, respectively. This is about 2 orders of magnitude higher than estimates for pure van-der-Waals agglomerates, but agrees quite well with other observations. Conclusion Although direct conclusions regarding the behavior of inhaled diesel aerosol in contact with body fluids cannot be drawn from such measurements, the results imply that highly agglomerated soot aerosol particles are unlikely to break up into units smaller than roughly the size distribution emitted as tail pipe soot. PMID:18533015

  16. NASA: Black soot fuels global warming

    CERN Multimedia

    2003-01-01

    New research from NASA's Goddard Space Center scientists suggests emissions of black soot have been altering the way sunlight reflects off Earth's snow. The research indicates the soot could be responsible for as much as 25 percent of global warming over the past century (assorted news items, 1 paragraph each).

  17. Empirical Temperature Measurement in Protoplanetary Disks

    Science.gov (United States)

    Weaver, Erik; Isella, Andrea; Boehler, Yann

    2018-02-01

    The accurate measurement of temperature in protoplanetary disks is critical to understanding many key features of disk evolution and planet formation, from disk chemistry and dynamics, to planetesimal formation. This paper explores the techniques available to determine temperatures from observations of single, optically thick molecular emission lines. Specific attention is given to issues such as the inclusion of optically thin emission, problems resulting from continuum subtraction, and complications of real observations. Effort is also made to detail the exact nature and morphology of the region emitting a given line. To properly study and quantify these effects, this paper considers a range of disk models, from simple pedagogical models to very detailed models including full radiative transfer. Finally, we show how the use of the wrong methods can lead to potentially severe misinterpretations of data, leading to incorrect measurements of disk temperature profiles. We show that the best way to estimate the temperature of emitting gas is to analyze the line peak emission map without subtracting continuum emission. Continuum subtraction, which is commonly applied to observations of line emission, systematically leads to underestimation of the gas temperature. We further show that once observational effects such as beam dilution and noise are accounted for, the line brightness temperature derived from the peak emission is reliably within 10%–15% of the physical temperature of the emitting region, assuming optically thick emission. The methodology described in this paper will be applied in future works to constrain the temperature, and related physical quantities, in protoplanetary disks observed with ALMA.

  18. Assessment of body temperature measurement options.

    Science.gov (United States)

    Sund-Levander, Märtha; Grodzinsky, Ewa

    Assessment of body temperature is important for decisions in nursing care, medical diagnosis, treatment and the need of laboratory tests. The definition of normal body temperature as 37°C was established in the middle of the 19th century. Since then the technical design and the accuracy of thermometers has been much improved. Knowledge of physical influence on the individual body temperature, such as thermoregulation and hormones, are still not taken into consideration in body temperature assessment. It is time for a change; the unadjusted mode should be used, without adjusting to another site and the same site of measurement should be used as far as possible. Peripheral sites, such as the axillary and the forehead site, are not recommended as an assessment of core body temperature in adults. Frail elderly individuals might have a low normal body temperature and therefore be at risk of being assessed as non-febrile. As the ear site is close to the hypothalamus and quickly responds to changes in the set point temperature, it is a preferable and recommendable site for measurement of body temperature.

  19. Instabilities and soot formation in spherically expanding, high pressure, rich, iso-octane-air flames

    Energy Technology Data Exchange (ETDEWEB)

    Lockett, R D [School of Engineering and Mathematical Sciences, City University, Northampton Square, London EC1V OHB (United Kingdom)

    2006-07-15

    Flame instabilities, cellular structures and soot formed in high pressure, rich, spherically expanding iso-octane-air flames have been studied experimentally using high speed Schlieren cinematography, OH fluorescence, Mie scattering and laser induced incandescence. Cellular structures with two wavelength ranges developed on the flame surface. The larger wavelength cellular structure was produced by the Landau-Darrieus hydrodynamic instability, while the short wavelength cellular structure was produced by the thermal-diffusive instability. Large negative curvature in the short wavelength cusps caused local flame quenching and fracture of the flame surface. In rich flames with equivalence ratio {phi} > 1.8, soot was formed in a honeycomb-like structure behind flame cracks associated with the large wavelength cellular structure induced by the hydrodynamic instability. The formation of soot precursors through low temperature pyrolysis was suggested as a suitable mechanism for the initiation of soot formation behind the large wavelength flame cracks.

  20. Application of the direct simulation Monte Carlo method to nanoscale heat transfer between a soot particle and the surrounding gas

    International Nuclear Information System (INIS)

    Yang, M.; Liu, F.; Smallwood, G.J.

    2004-01-01

    Laser-Induced Incandescence (LII) technique has been widely used to measure soot volume fraction and primary particle size in flames and engine exhaust. Currently there is lack of quantitative understanding of the shielding effect of aggregated soot particles on its conduction heat loss rate to the surrounding gas. The conventional approach for this problem would be the application of the Monte Carlo (MC) method. This method is based on simulation of the trajectories of individual molecules and calculation of the heat transfer at each of the molecule/molecule collisions and the molecule/particle collisions. As the first step toward calculating the heat transfer between a soot aggregate and the surrounding gas, the Direct Simulation Monte Carlo (DSMC) method was used in this study to calculate the heat transfer rate between a single spherical aerosol particle and its cooler surrounding gas under different conditions of temperature, pressure, and the accommodation coefficient. A well-defined and simple hard sphere model was adopted to describe molecule/molecule elastic collisions. A combination of the specular reflection and completely diffuse reflection model was used to consider molecule/particle collisions. The results obtained by DSMC are in good agreement with the known analytical solution of heat transfer rate for an isolated, motionless sphere in the free-molecular regime. Further the DSMC method was applied to calculate the heat transfer in the transition regime. Our present DSMC results agree very well with published DSMC data. (author)

  1. Turbine gas temperature measurement and control system

    Science.gov (United States)

    Webb, W. L.

    1973-01-01

    A fluidic Turbine Inlet Gas Temperature (TIGIT) Measurement and Control System was developed for use on a Pratt and Whitney Aircraft J58 engine. Based on engine operating requirements, criteria for high temperature materials selection, system design, and system performance were established. To minimize development and operational risk, the TIGT control system was designed to interface with an existing Exhaust Gas Temperature (EGT) Trim System and thereby modulate steady-state fuel flow to maintain a desired TIGT level. Extensive component and system testing was conducted including heated (2300F) vibration tests for the fluidic sensor and gas sampling probe, temperature and vibration tests on the system electronics, burner rig testing of the TIGT measurement system, and in excess of 100 hours of system testing on a J58 engine. (Modified author abstract)

  2. Developing a predictive model for the chemical composition of soot nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Violi, Angela [Univ. of Michigan, Ann Arbor, MI (United States); Michelsen, Hope [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hansen, Nils [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Wilson, Kevin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-04-07

    In order to provide the scientific foundation to enable technology breakthroughs in transportation fuel, it is important to develop a combustion modeling capability to optimize the operation and design of evolving fuels in advanced engines for transportation applications. The goal of this proposal is to develop a validated predictive model to describe the chemical composition of soot nanoparticles in premixed and diffusion flames. Atomistic studies in conjunction with state-of-the-art experiments are the distinguishing characteristics of this unique interdisciplinary effort. The modeling effort has been conducted at the University of Michigan by Prof. A. Violi. The experimental work has entailed a series of studies using different techniques to analyze gas-phase soot precursor chemistry and soot particle production in premixed and diffusion flames. Measurements have provided spatial distributions of polycyclic aromatic hydrocarbons and other gas-phase species and size and composition of incipient soot nanoparticles for comparison with model results. The experimental team includes Dr. N. Hansen and H. Michelsen at Sandia National Labs' Combustion Research Facility, and Dr. K. Wilson as collaborator at Lawrence Berkeley National Lab's Advanced Light Source. Our results show that the chemical and physical properties of nanoparticles affect the coagulation behavior in soot formation, and our results on an experimentally validated, predictive model for the chemical composition of soot nanoparticles will not only enhance our understanding of soot formation since but will also allow the prediction of particle size distributions under combustion conditions. These results provide a novel description of soot formation based on physical and chemical properties of the particles for use in the next generation of soot models and an enhanced capability for facilitating the design of alternative fuels and the engines they will power.

  3. The monolithic transition metal oxide crossed nanosheets used for diesel soot combustion under gravitational contact mode

    Science.gov (United States)

    Cao, Chunmei; Xing, Lingli; Yang, Yuexi; Tian, Ye; Ding, Tong; Zhang, Jing; Hu, Tiandou; Zheng, Lirong; Li, Xingang

    2017-06-01

    Crossed nanosheets of transition metal oxide (TMO-NS: Co-NS, Mn-NS and Fe-NS) were synthesized by a facile hydrothermal method and employed for soot combustion in the NO/O2/N2 and O2/N2 atmosphere under gravitational contact mode (GCM). They show high catalytic activities for soot combustion due to the macroporous structure of the as-prepare catalysts increasing the soot-catalyst contact efficiency. The XRD and XPS results reveal that the active phases in the corresponding catalysts exist as Co3O4, Mn2O3 and Fe2O3, respectively. Among these catalysts, the Co-NS shows the best activity for soot combustion, especially in the presence of NO, whose catalytic activity of T50 (391 °C) and SCO2 (100%) is as good as that of the Pt/Al2O3 catalyst. The excellent performance of the Co-NS catalyst results from several factors: the highest intrinsic activity (TOF = 1.77 × 10-5 s-1); the highest redox property as revealed by H2-TPR and soot-TPR; the largest amount of active oxygen species as clarified by XPS; the highest ability of NO oxidation to NO2 supported by NO-TPO. In addition, the multiporous structure of Co3O4 nanosheets is facilitated for the mass transfer. In the O2 atmosphere, soot particulates are directly oxidized by the surface adsorbed oxygen. After introducing of NO, the soot particulates are readily oxidized by NO2 at the low temperature (< 330 °C); with the increase of the reaction temperature (330-450 °C), both the active oxygen species and NO2 involve in soot combustion.

  4. Effect of aging on morphology, hygroscopicity, and optical properties of soot aerosol

    Science.gov (United States)

    Khalizov, A. F.; Xue, H.; Pagels, J.; McMurry, P. H.; Zhang, R.

    2009-12-01

    Soot from incomplete combustion represents one of the major forms of particulate matter pollution, profoundly impacting human health, air quality, and climate. The direct and indirect radiative effects of soot aerosol depend on particle composition and morphology, which may vary significantly when aerosol is subjected to atmospheric aging. We will present an overview of a comprehensive set of experimental measurements performed in our laboratory at Texas A&M to study the effect of internal mixing with atmospheric species on morphology, hygroscopicity, and optical properties of combustion soot. In our experiments, size-classified soot aerosol was exposed to 0.1 - 1000 ppb (part per billion) mixing ratios of sulfuric acid and dicarboxylic organic acids and resulting changes particle morphology and mixing state under dry and humid conditions were characterized through mass-mobility measurements by aerosol particle mass analyzer (APM) and tandem differential mobility analyzer (TDMA). Light absorption and scattering cross-sections for well-characterized fresh and coated soot aerosol were derived using a cavity ring-down spectrometer and an integrating nephelometer in order to assess the effect of atmospheric processing on the radiative properties of atmospheric soot. Internally mixed soot shows significant changes in particle morphology, increasing with the mass fraction of the coating material and relative humidity. Restructuring was the strongest for aggregates coated by sulfuric and glutaric acids whereas succinic acid coating did not result in observable morphology change. Sulfuric acid - coated particles experienced large hygroscopic growth at sub-saturated conditions and activated to cloud droplets at atmospherically relevant supersaturations. Furthermore, coating and subsequent hygroscopic growth considerably altered the optical properties of soot aerosol, increasing light scattering and absorption cross-sections. We found that irreversible restructuring of soot

  5. Laboratory setup for temperature and humidity measurements

    CERN Document Server

    Eimre, Kristjan

    2015-01-01

    In active particle detectors, the temperature and humidity conditions must be under constant monitoring and control, as even small deviations from the norm cause changes to detector characteristics and result in a loss of precision. To monitor the temperature and humidity, different kinds of sensors are used, which must be calibrated beforehand to ensure their accuracy. To calibrate the large number of sensors that are needed for the particle detectors and other laboratory work, a calibration system is needed. The purpose of the current work was to develop a laboratory setup for temperature and humidity sensor measurements and calibration.

  6. Cutting temperature measurement and material machinability

    Directory of Open Access Journals (Sweden)

    Nedić Bogdan P.

    2014-01-01

    Full Text Available Cutting temperature is very important parameter of cutting process. Around 90% of heat generated during cutting process is then away by sawdust, and the rest is transferred to the tool and workpiece. In this research cutting temperature was measured with artificial thermocouples and question of investigation of metal machinability from aspect of cutting temperature was analyzed. For investigation of material machinability during turning artificial thermocouple was placed just below the cutting top of insert, and for drilling thermocouples were placed through screw holes on the face surface. In this way was obtained simple, reliable, economic and accurate method for investigation of cutting machinability.

  7. Temperature measurements of shock-compressed deuterium

    International Nuclear Information System (INIS)

    Holmes, N.C.; Ross, M.; Nellis, W.J.

    1994-11-01

    The authors measured the temperatures of single and double-shocked D 2 and H 2 up to 85 GPa (0.85 Mbar) and 5,200 K. While single shock temperatures, at pressures to 23 GPa, agree well with previous models, the double shock temperatures are as much as 40% lower than predicted. This is believed to be caused by molecular dissociation, and a new model of the hydrogen EOS at extreme conditions has been developed which correctly predicts their observations. These data and model have important implications for programs which use condensed-phase hydrogen in implosion systems

  8. A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Pitz, W J; Curran, H J

    2005-11-14

    A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.

  9. Temperature measurements at the LMFBR core outlet

    International Nuclear Information System (INIS)

    Argous, J.P.; Berger, R.; Casejuane, R.; Fournier, C.; Girard, J.P.

    1980-04-01

    Over the last few years the temperature sensors used to measure the subassembly outlet temperature in French designed LMFBRs have been modified, basically in an effort to reduce the dispersion of the chromel-alumel thermocouple time constant, and to extend the frequency spectrum of the measurement signals by adding a steel electrode to from a stainless steel-sodium thermocouple. The result of this evolution is the temperature probe immersed in sodium which will be used in the SUPER PHENIX reactor. This paper describes the tests already completed or in progress on this probe. It also presents measurement data on the two basic probe parameters: the thermoelectric power of the stainless steel-sodium thermocouple and the time constant of the chromel-alumel thermocouple

  10. Dual neutron flux/temperature measurement sensor

    Science.gov (United States)

    Mihalczo, John T.; Simpson, Marc L.; McElhaney, Stephanie A.

    1994-01-01

    Simultaneous measurement of neutron flux and temperature is provided by a single sensor which includes a phosphor mixture having two principal constituents. The first constituent is a neutron sensitive 6LiF and the second is a rare-earth activated Y203 thermophosphor. The mixture is coated on the end of a fiber optic, while the opposite end of the fiber optic is coupled to a light detector. The detected light scintillations are quantified for neutron flux determination, and the decay is measured for temperature determination.

  11. Slot Antenna for Wireless Temperature Measurement Systems

    DEFF Research Database (Denmark)

    Acar, Öncel; Jakobsen, Kaj Bjarne

    2016-01-01

    This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

  12. Saturation effects in Na lidar temperature measurements

    International Nuclear Information System (INIS)

    von der Gathen, P.

    1991-01-01

    Na atoms residing in the 80-110 km altitude region can be used to probe the Doppler-broadened hyperfine structure (hfs) of their D 2 resonance by ground-bases lidar and hence to deduce atmospheric temperatures. In principle, two different methods may be employed: (1) wavelength scanning of the hfs with a narrow-band laser and signal detection with a broad-band receiver, and (2) use of a broad-band laser and wavelength scanning of the hfs with a narrow-band receiver. These two methods are affected in different ways by laser-induced saturation in the Na layer, the effect on the measurements of sodium densities and of atmospheric temperatures being quite different. Density measurements are affected by the absolute level of saturation. Temperature measurements, however, are affected by the difference in saturation at the scanned wavelengths. If, additionally, observed signal levels are taken into account, method 1 is more efficient than method 2 for both types of measurements at nighttime, whereas a modified method 2 surpasses method 1 for temperature measurements at daytime

  13. Ion temperature measurements in the Maryland Spheromak

    International Nuclear Information System (INIS)

    Gauvreau, J.L.

    1992-01-01

    Initial spectroscopic data from MS showed evidence of ion heating as deduced from the line widths of different ion species. Detailed measurements of OIV spectral emission line profiles in space and time revealed that heating takes place at early time, before spheromak formation and is occurring within the current discharge. The measured ion temperature is several times the electron temperature and cannot be explained by classical (Spitzer) resistivity. Classically, ions are expected to have lower temperatures than the electrons and therefore, lower temperatures than observed. High ion temperatures have been observed in different RFP's and Spheromaks but are usually associated with relaxation to the Taylor state and occur in the sustainment phase. During formation, the current delivered to start the discharge is not axisymmetric and as a consequence, X-points appear in the magnetic flux. A two dimensional analysis predicts that magnetic reconnection occurring at an X-point can give rise to high ion heating rates. A simple 0-dimensional calculation showed that within the first 20 μs, a conversion of mass flow kinetic energy into ion temperature could take place due to viscosity

  14. Emissions of soot particles from heat generators

    Science.gov (United States)

    Lyubov, V. K.; Popov, A. N.; Popova, E. I.

    2017-11-01

    «Soot carbon» or «Soot» - incomplete combustion or thermal decomposition particulate carbon product of hydrocarbons consisting of particles of various shapes and sizes. Soot particles are harmful substances Class 2 and like a dust dispersed by wind for thousands of kilometers. Soot have more powerful negative factor than carbon dioxide. Therefore, more strict requirements on ecological and economical performance for energy facilities at Arctic areas have to be developed to protect fragile Arctic ecosystems and global climate change from degradation and destruction. Quantity of soot particles in the flue gases of energy facilities is a criterion of effectiveness for organization of the burning process. Some of heat generators do not provide the required energy and environmental efficiency which results in irrational use of energy resources and acute pollution of environment. The paper summarizes the results of experimental study of solid particles emission from wide range of capacity boilers burning different organic fuels (natural gas, fuel oil, coal and biofuels). Special attention is paid to environmental and energy performance of the biofuels combustion. Emissions of soot particles PM2.5 are listed. Structure, composition and dimensions of entrained particles with the use of electronic scanning microscope Zeiss SIGMA VP were also studied. The results reveal an impact of several factors on soot particles emission.

  15. Measurement of rotational temperature at Kolhapur, India

    Directory of Open Access Journals (Sweden)

    G. K. Mukherjee

    2004-09-01

    Full Text Available Measurements of the hydroxyl rotational temperature for the (8,3 Meinel band have been reported from the observations of the ratio of the relative intensities of P1(2 and P1(4 lines of the OH(8,3 band at Kolhapur (16.8° N, 74.2° E, dip lat. 10.6° N in India during the period 1 November 2002-29 April 2003 using tilting-filter photometers. Mean values of rotational temperature have been computed for 60 nights. The monthly mean value of temperature lies in the range 194(±11-208(±18K. The mean rotational temperature obtained from all the measurements was found to be 202±15K. The results agree with other low-latitude measurements of rotational temperature using photometric airglow techniques. Quasi-periodic fluctuations with a period of about one to two hours have been prominent on many nights. Furthermore, the results show the general agreement between observations and model (MSIS-86 predictions.

  16. Measurement of rotational temperature at Kolhapur, India

    Directory of Open Access Journals (Sweden)

    G. K. Mukherjee

    2004-09-01

    Full Text Available Measurements of the hydroxyl rotational temperature for the (8,3 Meinel band have been reported from the observations of the ratio of the relative intensities of P1(2 and P1(4 lines of the OH(8,3 band at Kolhapur (16.8° N, 74.2° E, dip lat. 10.6° N in India during the period 1 November 2002-29 April 2003 using tilting-filter photometers. Mean values of rotational temperature have been computed for 60 nights. The monthly mean value of temperature lies in the range 194(±11-208(±18K. The mean rotational temperature obtained from all the measurements was found to be 202±15K. The results agree with other low-latitude measurements of rotational temperature using photometric airglow techniques. Quasi-periodic fluctuations with a period of about one to two hours have been prominent on many nights. Furthermore, the results show the general agreement between observations and model (MSIS-86 predictions.

  17. Single Particle Soot Photometer intercomparison at the AIDA chamber

    Directory of Open Access Journals (Sweden)

    M. Laborde

    2012-12-01

    Full Text Available Soot particles, consisting of black carbon (BC, organic carbon (OC, inorganic salts, and trace elements, are emitted into the atmosphere during incomplete combustion. Accurate measurements of atmospheric BC are important as BC particles cause adverse health effects and impact the climate.

    Unfortunately, the accurate measurement of the properties and mass concentrations of BC particles remains difficult. The Single Particle Soot Photometer (SP2 can contribute to improving this situation by measuring the mass of refractory BC in individual particles as well as its mixing state.

    Here, the results of the first detailed SP2 intercomparison, involving 6 SP2s from 6 different research groups, are presented, including the most evolved data products that can presently be calculated from SP2 measurements.

    It was shown that a detection efficiency of almost 100% down to 1 fg BC per particle can readily be achieved, and that this limit can be pushed down to ∼0.2 fg BC with optimal SP2 setup. Number and mass size distributions of BC cores agreed within ±5% and ±10%, respectively, in between the SP2s, with larger deviations in the range below 1 fg BC.

    The accuracy of the SP2's mass concentration measurement depends on the calibration material chosen. The SP2 has previously been shown to be equally sensitive to fullerene soot and ambient BC from sources where fossil fuel was dominant and less sensitive to fullerene soot than to Aquadag. Fullerene soot was therefore chosen as the standard calibration material by the SP2 user community; however, many data sets rely solely on Aquadag calibration measurements. The difference in SP2 sensitivity was found to be almost equal (fullerene soot to Aquadag response ratio of ∼0.75 at 8.9 fg BC for all SP2s. This allows the calculation of a fullerene soot equivalent calibration curve from a measured Aquadag calibration, when no fullerene soot calibration is available. It could be

  18. Temperature measurements in ZT-40M

    International Nuclear Information System (INIS)

    Little, E.M.; Haberstich, A.; Thomas, K.S.; Watt, R.G.

    1983-01-01

    Electron temperatures derived from Thomson scattering and ultrasoft x-ray (USXR) measurements taken before and after machine modifications are compared for ZT-40M. Modifications were made to the magnetic field windings to reduce field errors and the joints in the aluminum shell were coated with joint compound to reduce resistance and make all joints electrically uniform. These modifications resulted in increased plasma lifetime in ZT-40M from less than 10 ms to over 20 ms. Thomson scattering measurements were made with a single-point Thomson scattering apparatus. The scattered spectrum is collected by a three-grating spectrometer. The soft x rays are collected by a two-foil differential transmission system whose foil ratios may be easily varied. Before modifications the Thomson scattering and soft x-ray temperatures agreed up until 3 to 4 ms into the discharge. After this time the Thomson scattering temperature decreased slowly while the soft x-ray ''temperature'' increased rapidly. field errors resulted in Thomson scattering and USXR ''temperature'' time histories remaining fairly flat out to 10 to 11 ms, but introduced a small discrepancy (about 50 eV) in the absolute value of the temperatures. This change may be due either to the change in foil thickness used or to changes in radial temperature profiles. Profile changes may have been caused by the addition of four poloidal limiters or improvements to the magnetic field topology. After modifications the temperatures from both Thomson scattering and USXR were lower and the plasma density was higher. This is probably a result of the lower plasma-wall interaction with the new configuration

  19. Two methods to measure granular gas temperature

    Science.gov (United States)

    Chastaing, J.-Y.; Géminard, J.-C.; Naert, A.

    2017-07-01

    Grains are vibrated so as to achieve a granular gas, here regarded as an archetype of a dissipative non equilibrium steady state (NESS). We report on two distinct and concordant experimental measures of the system effective temperature. To do so, a blade fastened to the shaft of a small DC-motor, immersed in the grains, behaves as a driven 1D Brownian rotator, which is used as both actuator and sensor simultaneously. On the one hand, the Gallavotti-Cohen fluctuation theorem, which involves a measure of the asymmetry of the energy exchanges between the rotator and the NESS reservoir, provides a first effective temperature. On the other hand, the fluctuation-dissipation theorem, which involves the relation between the spontaneous fluctuations and the response to a weak perturbation, defines a second, independent, effective temperature. Both methods, even though they are based on drastically different ideas, give nicely concordant results.

  20. Measurement of very rapidly variable temperatures

    International Nuclear Information System (INIS)

    Elberg, S.; Mathonnet, P.

    1974-01-01

    Bibliographical research and visits to laboratories were undertaken in order to survey the different techniques used to measure rapidly variable temperatures, specifying the limits in maximum temperature and variation rate (time constant). On the basis of the bibliographical study these techniques were classified in three categories according to the physical meaning of their response time. Extension of the bibliographical research to methods using fast temperature variation measurement techniques and visits to research and industrial laboratories gave in an idea of the problems raised by the application of these methods. The use of these techniques in fields other than those for which they were developed can sometimes be awkward in the case of thermometric probe devices where the time constant cannot generally be specified [fr

  1. Tokamak Plasmas: Electron temperature $(T_ {e}) $ measurements ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 55; Issue 5-6. Tokamak Plasmas : Electron temperature ( T e ) measurements by Thomson scattering system. R Rajesh B Ramesh Kumar S K Varshney Manoj Kumar Chhaya Chavda Aruna Thakkar N C Patel Ajai Kumar Aditya Team. Contributed Papers Volume 55 ...

  2. New methode of measurement of temperature flow

    Directory of Open Access Journals (Sweden)

    Slávka Grexová

    2008-03-01

    Full Text Available The subject of this article is a measurement of thermal flow under laboratory conditions. We define the thermal flow as an amount of heat transmitted through a surface of rock over a certain period of time. According to the Atlas of Geothermal Energy, thermal flow ranges from 40 to 120 mW/m2. It is not possible to measure it directly on the rock surface. The conventional ways of measurement is a “separation bar” thermic conduction measurement system or measurement of the temperature of the rock in two different places at selected underground depth intervals. These measurements and analyses are not sufficient to make a final conclusion. It is necessary to repeat the measurements under real conditions.

  3. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-05-01

    Full Text Available CuO-CeO2 systems have been proposed as a promising catalyst for low temperature diesel-soot oxidation. CuO-CeO2 catalysts prepared by various methods were examined for air oxidation of the soot in a semi batch tubular flow reactor. The air oxidation of soot was carried out under tight contact with soot/catalyst ratio of 1/10. Air flow rate was 150 ml/min, soot-catalyst mixture was 110 mg, heating rate was 5 0C/min. Prepared catalysts were calcined at 500 0C and their stability was examined by further heating to 800 0C for 4 hours. It was found that the selectivity of all the catalysts was nearly 100% to CO2 production. It was observed that the activity and stability of the catalysts greatly influenced by the preparation methods. The strong interaction between CuO and CeO2 is closely related to the preparation route that plays a crucial role in the soot oxidation over the CuO-CeO2 catalysts. The ranking order of the preparation methods of the catalysts in the soot oxidation performance is as follows: sol-gel > urea nitrate combustion > Urea gelation method > thermal decomposition > co-precipitation. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 27th June 2010, Revised: 7th August 2010; Accepted: 13rd October 2010[How to Cite: R. Prasad, V.R. Bella. (2011. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 15-21. doi:10.9767/bcrec.6.1.822.15-21][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.822.15-21 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/822 | View in 

  4. Simultaneous schlieren photography and soot foil in the study of detonation phenomena

    Science.gov (United States)

    Kellenberger, Mark; Ciccarelli, Gaby

    2017-10-01

    The use of schlieren photography has been essential in unravelling the complex nature of high-speed combustion phenomena, but its line-of-sight integration makes it difficult to decisively determine the nature of multi-dimensional combustion wave propagation. Conventional schlieren alone makes it impossible to determine in what plane across the channel an observed structure may exist. To overcome this, a technique of simultaneous high-speed schlieren photography and soot foils was demonstrated that can be applied to the study of detonation phenomena. Using a kerosene lamp, soot was deposited on a glass substrate resulting in a semi-transparent sheet through which schlieren source light could pass. In order to demonstrate the technique, experiments were carried out in mixtures of stoichiometric hydrogen-oxygen at initial pressures between 10 and 15 kPa. Compared to schlieren imaging obtained without a sooted foil, high-speed video results show schlieren images with a small reduction of contrast with density gradients remaining clear. Areas of high temperature cause soot lofted from the foil to incandescence strongly, resulting in the ability to track hot spots and flame location. Post-processing adjustments were demonstrated to make up for camera sensitivity limitations to enable viewing of schlieren density gradients. High-resolution glass soot foils were produced that enable direct coupling of schlieren video to triple-point trajectories seen on the soot foils, allowing for the study of three-dimensional propagation mechanisms of detonation waves.

  5. The impact of carbon dioxide and exhaust gas recirculation on the oxidative reactivity of soot from ethylene flames and diesel engines

    Science.gov (United States)

    Al-Qurashi, Khalid O.

    Restrictive emissions standards to reduce nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel engines necessitate the development of advanced emission control technology. The engine manufacturers in the United States have implemented the exhaust gas recirculation (EGR) and diesel particulate filters (DPF) to meet the stringent emissions limits on NOx and PM, respectively. Although the EGR-DPF system is an effective means to control diesel engine emissions, there are some concerns associated with its implementation. The chief concern with this system is the DPF regenerability, which depends upon several factors, among which are the physicochemical properties of the soot. Despite the plethora of research that has been conducted on DPF regenerability, the impact of EGR on soot reactivity and DPF regenerability is yet to be examined. This work concerns the impact of EGR on the oxidative reactivity of diesel soot. It is part of ongoing research to bridge the gap in establishing a relationship between soot formation conditions, properties, and reactivity. This work is divided into three phases. In the first phase, carbon dioxide (CO2) was added to the intake charge of a single cylinder engine via cylinders of compressed CO2. This approach simulates the cold-particle-free EGR. The results showed that inclusion of CO2 changes the soot properties and yields synergistic effects on the oxidative reactivity of the resulting soot. The second phase of this research was motivated by the findings from the first phase. In this phase, post-flame ethylene soot was produced from a laboratory co-flow laminar diffusion flame to better understand the mechanism by which the CO2 affects soot reactivity. This phase was accomplished by successfully isolating the dilution, thermal, and chemical effects of the CO2. The results showed that all of these effects account for a measurable increase in soot reactivity. Nevertheless, the thermal effect was found to be the most

  6. Modelling and simulation of soot generation and transport

    OpenAIRE

    Hu, Xiaoqin

    2016-01-01

    Soot released from fires not only causes danger to lives and property damage, but also effects fire spread by altering the radiation characteristics of fire effluents. In many situations, it is the soot concentration that controls the fire development. Therefore, soot modelling is of great importance in fire safety science. This necessitates the development of a global and general soot model within fire field models that can simulate the amount of soot generated and transported in large-scale...

  7. Electrically heated particulate matter filter soot control system

    Science.gov (United States)

    Gonze, Eugene V.; Paratore, Jr., Michael J.; Bhatia, Garima

    2016-03-15

    A regeneration system includes a particulate matter (PM) filter with an upstream end for receiving exhaust gas and a downstream end. A control module determines a current soot loading level of the PM filter and compares the current soot loading level to a predetermined soot loading level. The control module permits regeneration of the PM filter when the current soot loading level is less than the predetermined soot loading level.

  8. Liquid temperature measuring method and device therefor

    International Nuclear Information System (INIS)

    Maruyama, Fumi; Karasawa, Hirokazu.

    1995-01-01

    In the present invention, temperature of liquid metal in coolants in an FBR type reactor can accurately be measured at rapid response time. Namely, ultrasonic waves are emitted from an ultrasonic wave sensor disposed in the air to a guide wave tube. Ultrasonic waves are reflected at reflection plates disposed at front and back or upper and lower portions of a small hole disposed to the wave guide tube. The reflected waves are received by the sensor described above. The difference of the reaching time of the reflected waves from the reflecting plates disposed at the front and the back or the upper and lower portions is measured. The speed of sounds in this case is determined based on the size of the small hole and the distance of the upper and the lower reflection plates. The speed of sounds is determined by the formula below: V(m/s) = 2500 - 0.52 T, where T: temperature. The temperature of the liquid can easily be calculated based on the formula. Accordingly, since the speed of the ultrasonic waves from their emission to the reception is msec order, and the processing of the signals are simple, the temperature can be measured at a response time of several msecs. In addition, since the ultrasonic wave sensor is disposed at the outside of the reactor, no special countermeasure for environmental circumstances is necessary, to improve maintenance ability. (I.S.)

  9. High temperature measurement of water vapor absorption

    Science.gov (United States)

    Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

    1985-01-01

    An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

  10. Plasma temperature measurements in disruption simulated experiment

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wurz, H. [Kernforschungszentrum Karlsruhe, INR (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)

    1995-12-31

    Results are reported of experiments to measure the temporal and spatial distributions of a temperature and radiation of a near surface plasma cloud appearing in the disruption simulated experiments. These measurements are needed to verificate the different numerical models of vapor shielding layer which appears to arise near the divertor plates surface and prevents them from the bulk of the incoming energy. Experiments with graphite and tungsten samples were carried out at the 2MK-200 plasma facility. Long CUSP trap was used as a source of high temperature deuterium plasma with a power density W = 10 MW/cm{sup 2} and time duration t = 20 mcs. Laser scattering, space and time resolved soft x-ray spectroscopy was employed to measure the plasma cloud temperature and radiation. The different behaviour of shielding layer parameters was shown for a graphite and tungsten samples. For a tungsten the sharp boundary existed between the incoming deuterium plasma and the thin layer of ablated material plasma and the strong gradient of electron temperature took place in this zone. For a graphite this boundary was broadened at the distance and the main part of the screening layer consisted of the mixture of the incoming deuterium and ablated carbon plasma. (orig.).

  11. On transient climate change at the Cretaceous-Paleogene boundary due to atmospheric soot injections

    Science.gov (United States)

    Bardeen, Charles G.; Garcia, Rolando R.; Toon, Owen B.; Conley, Andrew J.

    2017-09-01

    Climate simulations that consider injection into the atmosphere of 15,000 Tg of soot, the amount estimated to be present at the Cretaceous-Paleogene boundary, produce what might have been one of the largest episodes of transient climate change in Earth history. The observed soot is believed to originate from global wildfires ignited after the impact of a 10-km-diameter asteroid on the Yucatán Peninsula 66 million y ago. Following injection into the atmosphere, the soot is heated by sunlight and lofted to great heights, resulting in a worldwide soot aerosol layer that lasts several years. As a result, little or no sunlight reaches the surface for over a year, such that photosynthesis is impossible and continents and oceans cool by as much as 28 °C and 11 °C, respectively. The absorption of light by the soot heats the upper atmosphere by hundreds of degrees. These high temperatures, together with a massive injection of water, which is a source of odd-hydrogen radicals, destroy the stratospheric ozone layer, such that Earth’s surface receives high doses of UV radiation for about a year once the soot clears, five years after the impact. Temperatures remain above freezing in the oceans, coastal areas, and parts of the Tropics, but photosynthesis is severely inhibited for the first 1 y to 2 y, and freezing temperatures persist at middle latitudes for 3 y to 4 y. Refugia from these effects would have been very limited. The transient climate perturbation ends abruptly as the stratosphere cools and becomes supersaturated, causing rapid dehydration that removes all remaining soot via wet deposition.

  12. Electrometric aviation soot monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a highly sensitive and portable device to monitor soot particle mass distribution from aircraft engine exhaust. The proposed method is based on...

  13. Global rainbow refractometry for droplet temperature measurement

    Energy Technology Data Exchange (ETDEWEB)

    Pascal Lemaitre; Emmanuel Porcheron; Amandine Nuboer; Philippe Brun; Pierre Cornet; Jeanne Malet; Jacques Vendel; Laurent Bouilloux [Institut de Radioprotection et de Surete Nucleaire DSU/SERAC, BP 68, 91192 Gif-sur-Yvette Cedex (France); Gerard Grehan [UMR 6614 CORIA, Laboratoire d' Electromagnetisme et Systemes Particulaires Site Universitaire du Madrillet, Avenue de l' universite BP 12, 76 801 Saint Etienne du Rouvray Cedex, (France)

    2005-07-01

    Full text of publication follows: In order to establish an accurate database to characterize the heat and mass transfers between a spray and the atmosphere with thermal-hydraulic conditions representative of a hypothetical nuclear reactor accident in the containment enclosure of a pressurized water reactor (PWR), the French Institut de Radioprotection et de Surete Nucleaire (IRSN) has developed the TOSQAN experimental facility. This experiment is highly instrumented with non-intrusive diagnostics allowing to measure droplet size and velocity and gas concentrations [1]. The aim of this work is to present the Global Rainbow Thermometry (GRT), which is an advanced non-intrusive optical diagnostic, developed to measure the mean temperature of a set of falling droplets, in a measurement volume of 1 cm{sup 3}. The final paper will be divided in three parts. In the first one, we will explain the principle of the rainbow formation and how droplet temperature can be deduced from the rainbow analysis [2]. This part will be illustrated with the theoretical background on the rainbow and numerical simulations of the global rainbow. The second part will be devoted to present the global rainbow experimental set-up we have developed on optical table, its experimental qualification and finally its implementation on the TOSQAN facility [3]. Finally, we will present the temperature measurements achieved in TOSQAN for thermal-hydraulic conditions representative of a hypothetical nuclear reactor accident. These measurements are useful to characterize the heat and mass transfers between the spraying droplets and the air-steam mixture composing the atmosphere. This analysis will be exposed in a two companion papers. References: [1] E. Porcheron, P. Brun, P. Cornet, J. Malet, J. Vendel. Optical diagnostics applied for single and multi-phase flow characterization in the TOSQAN facility dedicated for thermal hydraulic containment studies. NURETH-10 Seoul, Korea, October 5-9, 2003. [2] P

  14. Global rainbow refractometry for droplet temperature measurement

    International Nuclear Information System (INIS)

    Pascal Lemaitre; Emmanuel Porcheron; Amandine Nuboer; Philippe Brun; Pierre Cornet; Jeanne Malet; Jacques Vendel; Laurent Bouilloux; Gerard Grehan

    2005-01-01

    Full text of publication follows: In order to establish an accurate database to characterize the heat and mass transfers between a spray and the atmosphere with thermal-hydraulic conditions representative of a hypothetical nuclear reactor accident in the containment enclosure of a pressurized water reactor (PWR), the French Institut de Radioprotection et de Surete Nucleaire (IRSN) has developed the TOSQAN experimental facility. This experiment is highly instrumented with non-intrusive diagnostics allowing to measure droplet size and velocity and gas concentrations [1]. The aim of this work is to present the Global Rainbow Thermometry (GRT), which is an advanced non-intrusive optical diagnostic, developed to measure the mean temperature of a set of falling droplets, in a measurement volume of 1 cm 3 . The final paper will be divided in three parts. In the first one, we will explain the principle of the rainbow formation and how droplet temperature can be deduced from the rainbow analysis [2]. This part will be illustrated with the theoretical background on the rainbow and numerical simulations of the global rainbow. The second part will be devoted to present the global rainbow experimental set-up we have developed on optical table, its experimental qualification and finally its implementation on the TOSQAN facility [3]. Finally, we will present the temperature measurements achieved in TOSQAN for thermal-hydraulic conditions representative of a hypothetical nuclear reactor accident. These measurements are useful to characterize the heat and mass transfers between the spraying droplets and the air-steam mixture composing the atmosphere. This analysis will be exposed in a two companion papers. References: [1] E. Porcheron, P. Brun, P. Cornet, J. Malet, J. Vendel. Optical diagnostics applied for single and multi-phase flow characterization in the TOSQAN facility dedicated for thermal hydraulic containment studies. NURETH-10 Seoul, Korea, October 5-9, 2003. [2] P

  15. Temperature measurement in French atomic piles

    International Nuclear Information System (INIS)

    Weill, J.; Rastoix, G.

    1950-10-01

    In the Chatillon reactor the temperature is measured (1) in the interior of one of the vertical A1 cylinders filled with UO 2 (temperature interval 20 to 70 deg. C), and (2) in the center of the tank containing D 2 O (20 to 50 deg. C). The instruments used are silver-constantan thermocouples; the wires are insulated by SiO 2 sheaths, those immersed in D 2 O being placed within Al cases 10 mm diameter. In the Saclay reactor the temperature is taken (1) in the interior of 4 U rods (20 to 300 deg. C), (2) at 2 points of the D 2 O mass (20 to 60 deg. C), (3) at one point in graphite (20 to 100 deg. C), and (4) at 5 points in the catalytic setup (200 deg. C). Copper-constantan couples are used (Ag-constantan is not suitable above 150 deg. C); the wires are enclosed in a sheath of glass fabric. In both reactors the accuracy of the temperature measurements is 0.5 deg. C. (author)

  16. Soot in the atmosphere and snow surface of Antarctica

    International Nuclear Information System (INIS)

    Warren, S.G.; Clarke, A.D.

    1990-01-01

    Samples of snow collected near the south pole during January and February 1986 were analyzed for the presence of light-absorbing particles by passing the melted snow through a nuclepore filter. Transmission of light through the filter showed that snow far from the station contains the equivalent of 0.1-0.3 ng of carbon per gram of snow (ng/g). Samples of ambient air were filtered and found to contain about 1-2 ng of carbon per kilogram of air, giving a scavenging ratio of about 150. The snow downwind of the station exhibited a well-defined plume of soot due to the burning of diesel fuel, but even in the center of the plume 1 km downwind, the soot concentration was only 3 ng/g, too small to affect snow albedo significantly. Measurements of snow albedo near large inland stations are therefore probably representative of their surrounding regions

  17. Measurements of temperature on LHC thermal models

    CERN Document Server

    Darve, C

    2001-01-01

    Full-scale thermal models for the Large Hadron Collider (LHC) accelerator cryogenic system have been studied at CERN and at Fermilab. Thermal measurements based on two different models permitted us to evaluate the performance of the LHC dipole cryostats as well as to validate the LHC Interaction Region (IR) inner triplet cooling scheme. The experimental procedures made use of temperature sensors supplied by industry and assembled on specially designed supports. The described thermal models took the advantage of advances in cryogenic thermometry which will be implemented in the future LHC accelerator to meet the strict requirements of the LHC for precision, accuracy, reliability, and ease-of-use. The sensors used in the temperature measurement of the superfluid (He II) systems are the primary focus of this paper, although some aspects of the LHC control system and signal conditioning are also reviewed. (15 refs).

  18. Formation, growth, and transport of soot in a three-dimensional turbulent non-premixed jet flame

    KAUST Repository

    Attili, Antonio

    2014-07-01

    The formation, growth, and transport of soot is investigated via large scale numerical simulation in a three-dimensional turbulent non-premixed n-heptane/air jet flame at a jet Reynolds number of 15,000. For the first time, a detailed chemical mechanism, which includes the soot precursor naphthalene and a high-order method of moments are employed in a three-dimensional simulation of a turbulent sooting flame. The results are used to discuss the interaction of turbulence, chemistry, and the formation of soot. Compared to temperature and other species controlled by oxidation chemistry, naphthalene is found to be affected more significantly by the scalar dissipation rate. While the mixture fraction and temperature fields show fairly smooth spatial and temporal variations, the sensitivity of naphthalene to turbulent mixing causes large inhomogeneities in the precursor fields, which in turn generate even stronger intermittency in the soot fields. A strong correlation is apparent between soot number density and the concentration of naphthalene. On the contrary, while soot mass fraction is usually large where naphthalene is present, pockets of fluid with large soot mass are also frequent in regions with very low naphthalene mass fraction values. From the analysis of Lagrangian statistics, it is shown that soot nucleates and grows mainly in a layer close to the flame and spreads on the rich side of the flame due to the fluctuating mixing field, resulting in more than half of the total soot mass being located at mixture fractions larger than 0.6. Only a small fraction of soot is transported towards the flame and is completely oxidized in the vicinity of the stoichiometric surface. These results show the leading order effects of turbulent mixing in controlling the dynamics of soot in turbulent flames. Finally, given the difficulties in obtaining quantitative data in experiments of turbulent sooting flames, this simulation provides valuable data to guide the development of

  19. NATO Workshop on Soot in Combustion Systems

    CERN Document Server

    Prado, G

    1983-01-01

    Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scie...

  20. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    Science.gov (United States)

    Adachi, K.; Buseck, P. R.

    2008-05-01

    Soot particles are major aerosol constituents that result from emissions of burning of fossil fuel and biomass. Because they both absorb sunlight and contribute to cloud formation, they are an influence on climate on local, regional, and global scales. It is therefore important to evaluate their optical and hygroscopic properties and those effects on the radiation budget. Those properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using transmission electron microscopy, we measured ~8000 particles (25 samples) with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC) and adjacent areas. More than 50% of the particles consist of internally mixed soot, organic matter, and sulfate. Imaging combined with chemical analysis of individual particles show that many are coated, consist of aggregates, or both. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetime. Our results suggest that a mixture of materials from multiple sources such as vehicles, power plants, and biomass burning occurs in individual particles, thereby increasing their complexity. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate than uncoated soot particles. Moreover, soot occurs in more than 60% of all particles in the MC plumes, suggesting its important role in the formation of secondary aerosol particles.

  1. Structure-reactivity correlation of diesel soot and characterization of polycyclic aromatic hydrocarbons and carbonyls in biofuel emissions; Struktur-Reaktivitaets-Korrelation von Dieselruss und Charakterisierung von PAHs und Carbonylen im Abgas von Biokraftstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Knauer, Markus

    2009-12-29

    This work reports on the determination of the structure-reactivity correlation of soot using Raman microscopy (RM) and temperature programmed oxidation (TPO), as well as on changes in the emission level of polycyclic aromatic hydrocarbons (PAH) and carbonyls at the combustion of biofuels. To characterize the reactivity of soot the combustion behaviour of model- and diesel soot has been determined by means of TPO in the presence of oxygen. In this context, spark-discharge soot and graphite powder were applied as model substances, and EURO VI and IV diesel soot as real-diesel soots. The structure of soot samples was investigated by RM and structural changes during the TPO were observed. In order to make a statement about the changes in PAH and carbonyl compound emissions during combustion of biofuels, samples were taken at different engine testbenches. Fossil fuel, biodiesel and vegetable oil were used during this study, as well as fuel mixtures with different biofuel fractions.

  2. Sea Surface Temperatures (SST): Significance and Measurement

    Science.gov (United States)

    Singer, S. F.

    2006-05-01

    Oceans cover 71 percent of Earth's surface and control the global climate. Quoted global mean temperature values and trends, largely based on land thermometers, differ substantially -" mainly because of uncertainties about SST. The ongoing controversy about the relative importance of natural climate changes and Anthropogenic Global Warming (AGW) revolves mainly around disparities between temperature trends of the atmosphere and surface (in the tropics and SH, i.e. mostly SST). Accurate measurement of SST is difficult. Geographic coverage is poor and there are many different techniques, each with its own problems and uncertainties: Water temperatures from buckets and ship-engine inlets; fixed and floating buoys; air temperatures from shipboard and island stations; and remote sensing from satellites using IR and microwaves. As is evident, each technique refers to a different level below the air-water interface. Drifter buoys (at around 50 cm) measure temperatures in the euphotic layers that are generally warmer than the bulk mixed layer sampled by ships (typically around 10 m). The IR emission arises from a 10-micron-thick skin that interacts dynamically with the underlying "mixed layer." The microwave data depend also on emissivity and therefore on surface roughness and sea state. SST data derived from corals provide some support for instrumental data but are not conclusive. The majority of corals show a warming trend since 1979; others show cooling or are ambiguous. There are different ways of interpreting this result. Physical optics dictates that the downwelling IR radiation from atmospheric greenhouse gases is absorbed in the first instance within the skin. Only direct measurements can establish how much of this energy is shared with the bulk mixed layer (to which the usual SST values refer.). SST controls evaporation and therefore global precipitation. SST influences tropical cyclones and sea-level rise; but there is lively debate on those issues. Changes in

  3. Temperature measuring element in nuclear reactors

    International Nuclear Information System (INIS)

    Wada, Takashi.

    1987-01-01

    Purpose: To easily measure the partial maximum temperature at a portion within the nuclear reactor where the connection with the external portion is difficult. Constitution: Sodium, potassium or the alloy thereof with high heat expansion coefficient is packed into an elastic vessel having elastic walls contained in a capsule. A piercing member formed into an acute triangle is attached to one end in the direction of expansion and contraction of the elastic container. The two sides of the triangle form an acute knife edge. A diaphragm is disposed within a capsule at a position opposed to the sharpened direction of the piercing member. Such a capsule is placed in a predetermined position of the nuclear reactor. The elastic vessel causes thermal expansion displacement depending on the temperature at a certain position, by which the top end of the pierce member penetrates through the diaphragm. A pierced scar of a penetration length depending on the temperature is resulted to the diaphragm. The length of the piercing damage is electroscopically observed and compared with the calibration curve to recognize the maximum temperature in the predetermined portion of the nuclear reactor. (Kamimura, M.)

  4. Uncertainty evaluation in transition temperature measurements

    Energy Technology Data Exchange (ETDEWEB)

    Brillaud, C. [Electricite de France, Avoine (France); Augendre, H. [Electricite de France, Clamart (France); Bethmont, M. [Electricite de France, Ecuelles (France)

    1996-12-31

    The pressure vessel surveillance program is mainly based on the transition temperature change assessment, a change which is induced by neutron irradiation. Uncertainties in Charpy test measurements are well known; however, the authors are less familiar with uncertainties due to general procedures governing experiments, which can be significant and therefore must be taken into account. In fact, procedures specify neither the number of specimens needed to obtain a transition curve, nor the choice of test temperatures, nor the fitting method for the transition curve. A study has been conducted to determine the influence of the experimental procedure on the accuracy of transition temperature determination, and the initial results are presented in this paper. Two EDF laboratories performed Charpy tests on the surveillance program reference metal, using 8, 16, 24, 32 and 64 specimens to evaluate how the number of specimens affects the transition temperature. The influence of the scatter of mechanical properties has also been studied at two levels of irradiation. The authors have evaluated the effect of different sampling strategies and investigated a new fitting method, which is based on a simultaneous fitting of all curves with common constraints on parameters.

  5. Temperature measurements during laser skin welding

    Science.gov (United States)

    Fried, Nathaniel M.; Choi, Bernard; Welch, Ashley J.; Walsh, Joseph T., Jr.

    1999-06-01

    A thermal camera was used to measure surface temperatures during laser skin welding to provide feedback for optimization of the laser parameters. Two-cm-long, full- thickness incisions were made in guinea pig skin. India ink was used as an absorber. Continuous-wave, 1.06-μm, Nd:YAG laser radiation was scanned over the incisions, producing a pulse duration of approximately 100 ms. Cooling durations between scans of 1.6, 4.0, and 8.0 s were studied with total operation times of 3, 5, and 10 min, respectively. A laser spot diameter of 5 mm was used with the power constant at 10 W. Thermal images were obtained at 30 frames per second with a thermal camera detecting 3.5 micrometers radiation. Surface temperatures were recorded at 0, 1, and 6 mm from the center line of the incision. Cooling durations between scans of 1.6 s and 4.0 s in vitro resulted in temperatures at the weld site remaining above ~65°C for prolonged periods of time. Cooling durations between scans as long as 8.0 s were sufficient both in vitro and in vivo to prevent a significant rise in baseline temperatures at the weld site over time.

  6. An Experimental and Computational Study on Soot Formation in a Coflow Jet Flame Under Microgravity and Normal Gravity

    Science.gov (United States)

    Ma, Bin; Cao, Su; Giassi, Davide; Stocker, Dennis P.; Takahashi, Fumiaki; Bennett, Beth Anne V.; Smooke, Mitchell D.; Long, Marshall B.

    2014-01-01

    Upon the completion of the Structure and Liftoff in Combustion Experiment (SLICE) in March 2012, a comprehensive and unique set of microgravity coflow diffusion flame data was obtained. This data covers a range of conditions from weak flames near extinction to strong, highly sooting flames, and enabled the study of gravitational effects on phenomena such as liftoff, blowout and soot formation. The microgravity experiment was carried out in the Microgravity Science Glovebox (MSG) on board the International Space Station (ISS), while the normal gravity experiment was performed at Yale utilizing a copy of the flight hardware. Computational simulations of microgravity and normal gravity flames were also carried out to facilitate understanding of the experimental observations. This paper focuses on the different sooting behaviors of CH4 coflow jet flames in microgravity and normal gravity. The unique set of data serves as an excellent test case for developing more accurate computational models.Experimentally, the flame shape and size, lift-off height, and soot temperature were determined from line-of-sight flame emission images taken with a color digital camera. Soot volume fraction was determined by performing an absolute light calibration using the incandescence from a flame-heated thermocouple. Computationally, the MC-Smooth vorticity-velocity formulation was employed to describe the chemically reacting flow, and the soot evolution was modeled by the sectional aerosol equations. The governing equations and boundary conditions were discretized on an axisymmetric computational domain by finite differences, and the resulting system of fully coupled, highly nonlinear equations was solved by a damped, modified Newtons method. The microgravity sooting flames were found to have lower soot temperatures and higher volume fraction than their normal gravity counterparts. The soot distribution tends to shift from the centerline of the flame to the wings from normal gravity to

  7. Numerical investigation of soot formation and oxidation processes under large two-stroke marine diesel engine-like conditions using integrated CFD-chemical kinetics

    DEFF Research Database (Denmark)

    Pang, Kar Mun; Karvounis, Nikolas; Walther, Jens Honore

    2016-01-01

    skeletal model are close to those produced by the larger and more comprehensive chemical mechanisms, apart from those at the low pressure condition. The current study also demonstrates that the variation of averaged soot volume fraction with respect to the change of combustion chamber pressure captured...... using the revised soot model agrees reasonably well with the measurements in terms of peak values. The numerical model is subsequently applied to investigate the flame development, soot/nitrogen monoxide formation and heat transfer in a two-stroke, low-speed uniflow-scavenged marine diesel engine......% higher compared to that when only convective heat loss is considered. The averaged nitrogen monoxide concentration is 7.7% lower when both convective and soot radiative heat losses are accounted for but the net soot mass production is less sensitive to soot radiation. A sensitivity study reveals...

  8. Infrared radiometric technique in temperature measurement

    Science.gov (United States)

    Glazer, S.; Madding, R.

    1988-01-01

    One class of commercially available imaging infrared radiometers using cooled detectors is sensitive to radiation over the 3 to 12 micron wavelength band. Spectral filters can tailor instrument sensitivity to specific regions where the target exhibits optimum radiance. The broadband spectral response coupled with real time two-dimensional imaging and emittance/background temperature corrections make the instruments useful for remote measurement of surface temperatures from -20 C to +1500 C. Commonly used radiometric techniques and assumptions are discussed, and performance specifications for a typical modern commercial instrument are presented. The potential usefulness of an imaging infrared radiometer in space laboratories is highlighted through examples of research, nondestructive evaluation, safety, and routine maintenance applications. Future improvements in instrument design and application of the radiometric technique are discussed.

  9. Synthetic fuel combustion: pollutant formation. Soot initiation mechanisms in burning aromatics. First quarterly report, 19 September-31 December 1980

    Energy Technology Data Exchange (ETDEWEB)

    Rawlins, W. T.; Tanzawa, T.

    1981-01-01

    Although considerable progress has been made in recent years in understanding the phenomenology of soot formation in the combustion of hydrocarbon fuels, relatively little attention has been focused upon aromatic fuels of the types commonly found in coal liquids. In particular, the effects of gas-phase free radicals, formed during combustion, on the kinetics of formation of incipient soot particles have not been characterized. Accordingly, an experimental investigation of the detailed kinetics of incipient soot formation in the combustion and pyrolysis of aromatic fuels of the benzene, anisole, phenol, and pyrrole families has been initiated in order to determine soot formation mechanisms and rate parameters. The experiments will be performed in a shock tube over the temperature range 1300 to 2500 K, using multiple ultraviolet, visible, and infrared diagnostics to monitor the kinetic behavior of free radicals (such as OH), incipient soot particles, and combustion products. Experiments will be conducted with artificially enhanced concentrations of free radicals such as OH and O to determine their effects on the kinetics of soot and soot precursors. The experimental work will be supported and directed by a parallel analytical effort using a detailed mechanistic model of the chemical kinetics and dynamics of the reacting systems. In this report, the design and configuration of the experimental apparatus are described, the details of the kinetic model are outlined, and possible reaction pathways are discussed.

  10. Delayed condensation and frost formation on superhydrophobic carbon soot coatings by controlling the presence of hydrophilic active sites

    Science.gov (United States)

    Esmeryan, Karekin D.; Castano, Carlos E.; Mohammadi, Reza; Lazarov, Yuliyan; Radeva, Ekaterina I.

    2018-02-01

    Condensation frosting is an undesired natural phenomenon that could be impeded efficiently using appropriate wettability and morphologically patterned surfaces. The icephobic properties of carbon soot and the fabrication scalability of its synthesis method are a good foundation for anti-frosting applications; however, the fundamentals of frost growth and spreading on sooted surfaces have not been examined yet. In this study, we investigate the anti-frosting performance of three groups of superhydrophobic soot coatings by means of 16 MHz quartz crystal microbalances (QCMs). The analysis of the real-time sensor signal of each soot coated QCM pattern shows that frost formation and its propagation velocity depend on the quantity of oxygen functionalities and structural defects in the material. In turn, the reduction of both parameters shifts the onset of frost growth to temperatures below  -20 °C, whereas the interdroplet ice bridging is slowed by a factor of four. Moreover, high-resolution scanning electron micrographs of the samples imply delamination upon defrosting of the soot with spherical-like morphology via polar interactions driven mechanism. These results reveal an opportunity for control of frost incipiency on sooted surfaces by adjusting the synthesis conditions and depositing soot coatings with as low as possible content of hydrophilic active sites.

  11. Effects of carbon dioxide on isolated droplet combustion for sooting and non-sooting fuels in microgravity

    Science.gov (United States)

    Nakaya, Shinji; Furuta, Tomoya; Nagashima, Yoshiaki; Segawa, Daisuke; Kadota, Toshikazu

    The combustion behavior of ethanol, n-buthanol and n-decane droplets in high concentration of CO2 was experimentally investigated at atmospheric pressure in microgravity. Experiments were performed during a fall of the experimental setup at 1 s drop tower with the total height of 9 m. The initial droplet diameter was ranged from about 0.3 to 0.8 mm. Detail measurements of the projected image of the droplet are conducted by using a high speed video camera and the effective droplet diameter squared are calculated from the surface area of the rotating body of the projected object. Effects of ambient carbon dioxide on unsteady behavior of the instantaneous burning rate for sooting and non-sooting droplet flames were investigated. The behavior of the instantaneous burning rate clearly showed events of the initial thermal expansion, ignition and subsequent burning of the fuel droplet, and it was different from the behavior predicted by d2 law. These fundamental behaviors for ethanol, n-buthanol and n-decane were shown in air and high concentrations of ambient carbon dioxide. In the case of n-decane (sooting fuel), the change in the burning rate after ignition was great while it was small in the case of ethanol. A stepwise increase in the burning rate after ignition could be clearly seen for n-decane droplet when initial droplet diameter was large although the tendency was not observed for ethanol. However, this stepwise behavior disappeared in high concentration of ambient carbon dioxide. In high concentration of ambient carbon dioxide, non-luminous flame was formed. The mitigation of soot production by ambient carbon dioxide was clearly observed and this effect was greater for the smaller droplet.

  12. Apparatus for accurately measuring high temperatures

    Science.gov (United States)

    Smith, D.D.

    The present invention is a thermometer used for measuring furnace temperatures in the range of about 1800/sup 0/ to 2700/sup 0/C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  13. Effect of fuel molecular structure on soot formation in gas turbine combustion

    Science.gov (United States)

    Naegeli, D. W.; Moses, C. A.

    1980-01-01

    The effect of fuel variations at the same hydrogen content on the formation of soot in a gas turbine combustor was studied. Six fuels were burned to a combustor over a matrix of about 50 test conditions with test conditions ranging over 500-1800 kPa (5-18 atm) pressure and 500-1000 K burner inlet temperature; fuel-air ratios were varied from 0.008-0.024. Flame radiation measurements were made through a sapphire window toward the end of the primary zone. The hydrogen content of the six test fuels ranged from 12.80 to 12.88%. Five fuels emphasized hydrocarbon types: (mono, di, and tricyclic), naphthenes (decalin) and partially hydrogenated aromatics (tetralin); the sixth fuel emphasized final boiling point.

  14. Modelling and Simulation of Packed Bed Catalytic Converter for Oxidation of Soot in Diesel Powered Vehicles Flue Gas

    Directory of Open Access Journals (Sweden)

    Mohammad Nasikin

    2010-10-01

    Full Text Available Diesel vehicle is used in Indonesia in very big number. This vehicle exhausts pollutants especially diesel soot that can be reduces by using a catalytic converter to convert the soot to CO2. To obtain the optimal dimension of catalytic converter it is needed a model that can represent the profile of soot weight, temperature and pressure along the catalytic converter. In this study, a model is developed for packed bed catalytic converter in an adiabatic condition based on a kinetic study that has been  reported previously. Calculation of developed equations in this model uses Polymath 5.X solver with Range Kutta Method. The simulation result shows that temperature profile along catalytic converter increases with the decrease of soot weight,  while pressure profile decreases. The increase of soot weight in entering gas increases the needed converter length. On the other hand, the increase of catalyst diameter does not affect to soot weight along converter and temperature profile, but results a less pressure drop. For 2.500 c diesel engine, packed bed catalytic converter with ellipse's cross sectional of 14,5X7,5 cm diagonal and 0,8 cm catalyst particle diameter, needs 4,1 cm length.

  15. Toluene pyrolysis studies and high temperature reactions of propargyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Kern, R.D.; Chen, H.; Qin, Z. [Univ. of New Orleans, LA (United States)

    1993-12-01

    The main focus of this program is to investigate the thermal decompositions of fuels that play an important role in the pre-particle soot formation process. It has been demonstrated that the condition of maximum soot yield is established when the reaction conditions of temperature and pressure are sufficient to establish a radical pool to support the production of polyaromatic hydrocarbon species and the subsequent formation of soot particles. However, elevated temperatures result in lower soot yields which are attributed to thermolyses of aromatic ring structures and result in the bell-shaped dependence of soot yield on temperature. The authors have selected several acyclic hydrocarbons to evaluate the chemical thermodynamic and kinetic effects attendant to benzene formation. To assess the thermal stability of the aromatic ring, the authors have studied the pyrolyses of benzene, toluene, ethylbenzene, chlorobenzene and pyridine. Time-of-flight mass spectrometry (TOF) is employed to analyze the reaction zone behind reflected shock waves. Reaction time histories of the reactants, products, and intermediates are constructed and mechanisms are formulated to model the experimental data. The TOF work is often performed with use of laser schlieren densitometry (LS) to measure density gradients resulting from the heats of various reactions involved in a particular pyrolytic system. The two techniques, TOF and LS, provide independent and complementary information about ring formation and ring rupture reactions.

  16. Numerical investigation on soot particles emission in compression ignition diesel engine by using particulate mimic soot model

    Directory of Open Access Journals (Sweden)

    Ibrahim Fadzli

    2017-01-01

    Full Text Available Research via computational method, specifically by detailed-kinetic soot model offers much more advantages than the simple model as more detailed formation/oxidation process is taken into consideration, thus providing better soot mass concentration, soot size, soot number density as well as information regarding other related species. In the present computational study, investigation of in-cylinder soot concentration as well as other emissions in a single cylinder diesel engine has been conducted, using a commercial multidimensional CFD software, CONVERGE CFD. The simulation was carried out for a close-cycle combustion environment from inlet valve closing (IVC to exhaust valve opening (EVO. In this case, detailed-kinetic Particulate Mimic (PM soot model was implemented as to take benefit of the method of moment, instead of commonly implemented simple soot model. Analyses of the results are successfully plotted to demonstrate that the soot size and soot mass concentration are strongly dependent on the detailed soot formation and oxidation process rates. The calculated of soot mass concentration and average soot size at EVO provide the end value of 29.2 mg/m3 and 2.04 × 10−8 m, respectively. Besides, post-processing using EnSight shows the qualitative results of soot concentration along simulation period in the combustion chamber.

  17. Post-depositional enrichment of black soot in snow-pack and accelerated melting of Tibetan glaciers

    International Nuclear Information System (INIS)

    Xu Baiqing; Joswiak, Daniel R; Zhao Huabiao; Cao Junji; Liu Xianqin; He Jianqiao

    2012-01-01

    The post-depositional enrichment of black soot in snow-pack was investigated by measuring the redistribution of black soot along monthly snow-pits on a Tien Shan glacier. The one-year experiment revealed that black soot was greatly enriched, defined as the ratio of concentration to original snow concentration, in the unmelted snow-pack by at least an order of magnitude. Greatest soot enrichment was observed in the surface snow and the lower firn-pack within the melt season percolation zone. Black carbon (BC) concentrations as high as 400 ng g −1 in the summer surface snow indicate that soot can significantly contribute to glacier melt. BC concentrations reaching 3000 ng g −1 in the bottom portion of the firn pit are especially concerning given the expected equilibrium-line altitude (ELA) rise associated with future climatic warming, which would expose the dirty underlying firn and ice. Since most of the accumulation area on Tibetan glaciers is within the percolation zone where snow densification is characterized by melting and refreezing, the enrichment of black soot in the snow-pack is of foremost importance. Results suggest the effect of black soot on glacier melting may currently be underestimated. (letter)

  18. Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

    Science.gov (United States)

    Kameya, Yuki; Lee, Kyeong O.

    2013-10-01

    Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed.

  19. Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

    International Nuclear Information System (INIS)

    Kameya, Yuki; Lee, Kyeong O.

    2013-01-01

    Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed

  20. Soot formation in a blast furnace - Prediction via a parametric study, using detailed kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nordstroem, T.; Kilpinen, P.; Hupa, M. [Aabo Akademi, Turku (Finland). Combustion Chemistry Group

    1996-12-31

    The objective of this work has been to investigate the soot formation in a blast furnace fired with heavy fuel oil, using detailed kinetic modelling. This work has been concentrated on parameter studies that could explain under which conditions soot is formed and how that formation could be avoided. The parameters investigated were temperature, pressure, stoichiometric ratio, pyrolysis gas composition and reactor model. The calculations were based on a reaction mechanism that consists of 100 species and 446 reactions including polyaromatic hydrocarbons (PAM) up to 7 aromatic rings SULA 2 Research Programme; 4 refs.

  1. Biomass Gasification Behavior in an Entrained Flow Reactor: Gas Product Distribution and Soot Formation

    DEFF Research Database (Denmark)

    Qin, Ke; Jensen, Peter Arendt; Lin, Weigang

    2012-01-01

    Biomass gasification and pyrolysis were studied in a laboratory-scale atmospheric pressure entrained flow reactor. Effects of operating parameters and biomass types on the syngas composition were investigated. In general, the carbon conversion during biomass gasification was higher than 90......% at the optimal conditions of 1400 °C with steam addition. The biomass carbon that was not converted to gas in the gasification process only appeared as soot particles in the syngas in all of the experiments, except for the two experiments performed at 1000 °C, where a very small amount of char was also left....... In comparison to pyrolysis, lower yields of soot, H2, and CO were produced during gasification. The yield of soot could be reduced by a longer residence time, larger feeder air flow, lower oxygen concentration, higher excess air ratio, higher steam/carbon ratio, and higher reactor temperature. Changes...

  2. Optical characterization of multi-scale morphologically complex heterogeneous media - Application to snow with soot impurities

    Science.gov (United States)

    Dai, Xiaoyu; Haussener, Sophia

    2018-02-01

    A multi-scale methodology for the radiative transfer analysis of heterogeneous media composed of morphologically-complex components on two distinct scales is presented. The methodology incorporates the exact morphology at the various scales and utilizes volume-averaging approaches with the corresponding effective properties to couple the scales. At the continuum level, the volume-averaged coupled radiative transfer equations are solved utilizing (i) effective radiative transport properties obtained by direct Monte Carlo simulations at the pore level, and (ii) averaged bulk material properties obtained at particle level by Lorenz-Mie theory or discrete dipole approximation calculations. This model is applied to a soot-contaminated snow layer, and is experimentally validated with reflectance measurements of such layers. A quantitative and decoupled understanding of the morphological effect on the radiative transport is achieved, and a significant influence of the dual-scale morphology on the macroscopic optical behavior is observed. Our results show that with a small amount of soot particles, of the order of 1ppb in volume fraction, the reduction in reflectance of a snow layer with large ice grains can reach up to 77% (at a wavelength of 0.3 μm). Soot impurities modeled as compact agglomerates yield 2-3% lower reduction of the reflectance in a thick show layer compared to snow with soot impurities modeled as chain-like agglomerates. Soot impurities modeled as equivalent spherical particles underestimate the reflectance reduction by 2-8%. This study implies that the morphology of the heterogeneities in a media significantly affects the macroscopic optical behavior and, specifically for the soot-contaminated snow, indicates the non-negligible role of soot on the absorption behavior of snow layers. It can be equally used in technical applications for the assessment and optimization of optical performance in multi-scale media.

  3. Carbon Nanostructure of Diesel Soot Particles Emitted from 2 and 4 Stroke Marine Engines Burning Different Fuels.

    Science.gov (United States)

    Lee, Won-Ju; Park, Seul-Hyun; Jang, Se-Hyun; Kim, Hwajin; Choi, Sung Kuk; Cho, Kwon-Hae; Cho, Ik-Soon; Lee, Sang-Min; Choi, Jae-Hyuk

    2018-03-01

    Diesel soot particles were sampled from 2-stroke and 4-stroke engines that burned two different fuels (Bunker A and C, respectively), and the effects of the engine and fuel types on the structural characteristics of the soot particle were analyzed. The carbon nanostructures of the sampled particles were characterized using various techniques. The results showed that the soot sample collected from the 4-stroke engine, which burned Bunker C, has a higher degree of order of the carbon nanostructure than the sample collected from the 2-stroke engine, which burned Bunker A. Furthermore, the difference in the exhaust gas temperatures originating from the different engine and fuel types can affect the nanostructure of the soot emitted from marine diesel engines.

  4. Kinetics and mechanism of soot formation in hydrocarbon combustion

    Science.gov (United States)

    Frenklach, Michael

    1990-01-01

    The focus of this work was on kinetic modeling. The specific objectives were: detailed modeling of soot formation in premixed flames, elucidation of the effects of fuel structure on the pathway to soot, and the development of a numerical technique for accurate modeling of soot particle coagulation and surface growth. Those tasks were successfully completed and are briefly summarized.

  5. Catalytic soot oxidation over Ce- and Cu-doped hydrotalcites-derived mesoporous mixed oxides.

    Science.gov (United States)

    Wang, Zhongpeng; Wang, Liguo; He, Fang; Jiang, Zheng; Xiao, Tiancun; Zhang, Zhaoliang

    2014-09-01

    Ce- and Cu-doped hydrotalcites derived mixed oxides were prepared through co-precipitation and calcination method, and their catalytic activities for soot oxidation with O2 and O2/NO were investigated. The solids were characterized by XRD, TG-DTG, BET, H2-TPR, in situ FTIR and TPO techniques. All the catalysts precursors showed the typical diffraction patterns of hydrotalcite-like materials having layered structure. The derived mixed oxides exhibited mesoporous properties with specific surface area of 45-160 m2/g. After both Ce and Cu incorporated, mixed crystalline phases of CuO (tenorite), CeO2 (fluorite) and MgAl2O4 (spinel) were formed. As a result, the NO(x) adsorption capacity of this catalyst was largely increased to 201 μmol/g, meanwhile, it was also the most effective to convert NO into NO2 in the sorption process due to the enhanced reducibility. The in situ FTIR spectra revealed that NO(x) were stored mainly as chelating bidentate and monodentate nitrate. The interaction effect between Cu and Ce in the mixed oxide resulted in different NO(x) adsorption behavior. Compared with the non-catalyzed soot oxidation, soot conversion curves over the mixed oxides catalysts shift to low temperature in O2. The presence of NO in the gas phase significantly enhanced the soot oxidation activity with ignition temperature decreased to about 320 degrees C, which is due to NO conversion to NO2 over the catalyst followed by the reaction of NO2 with soot. This explains the cooperative effect of Ce and Cu in the mixed oxide on soot oxidation with high activity and 100% selectivity to CO2 formation.

  6. Characterizing germania concentration and structure in fiber soot using multiphoton microscopy and spectroscopy technology

    Science.gov (United States)

    Chen, Minghan; Li, Ming-Jun; Liu, Anping

    2015-02-01

    Germania doping is commonly used in the core of optical fiber due to its advantages compared to other materials such as superior transparency in near-infrared telecommunication wavelength region. During fiber preform manufacturing using the outside vapor deposition (OVD) process, Ge is doped into a silica soot preform by chemical vapor deposition. Since the Ge doping concentration profile is directly correlated with the fiber refractive index profile, its characterization is critical for the fiber industry. Electron probe micro-analyzer (EPMA) is a conventional analysis method for characterizing the Ge concentration profile. However, it requires extensive sample preparation and lengthy measurement. In this paper, a multiphoton microscopy technique is utilized to measure the Ge doping profile based on the multiphoton fluorescence intensity of the soot layers. Two samples, one with ramped and another with stepped Ge doping profiles were prepared for measurements. Measured results show that the technique is capable of distinguishing ramped and stepped Ge doping profiles with good accuracy. In the ramped soot sample, a sharp increment of doping level was observed in about 2 mm range from soot edge followed by a relative slow gradient doping accretion. As for the stepped doping sample, step sizes ranging from around 1 mm (at soot edge) to 3 mm (at soot center) were observed. All the measured profiles are in close agreement with that of the EPMA measurements. In addition, both multiphoton fluorescence (around 420 nm) and sharp second harmonic generations (at 532 nm) were observed, which indicates the co-existence of crystal and amorphous GeO2.

  7. Improved soot blowing, based on needs, using the mechanical characteristics of the steam pipe - stage 2; Foerbaettrad behovsstyrd sotning med hjaelp av vaermeoeverfoerande tubens mekaniska egenskaper - etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Elisabet; Fredoe, Claes; Gabrielsson, Lars; Eriksson, Daniel

    2011-10-15

    The detection of contamination of the boiler tubes through the tube mechanical properties has been studied. The project has carried out measurements and detection of three different boilers with different conditions in terms of sooting philosophy, combustion method and sooting method. The assembly of the detecting strain gauge takes place on a clip which is screwed and glued onto the tube.

  8. Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials

    Directory of Open Access Journals (Sweden)

    Ganesh Chandra Dhal

    2017-04-01

    Full Text Available In this research paper, the nanometric size effect, the effects of the intrinsic factors including structure, and the redox properties of three systems of nanometric of silver-based catalysts were summarized. In this work, these catalysts were investigated for the simultaneous removal of particulate matter (diesel soot, and NOX was compared with that of a model of Pt-Ba/Al2O3 catalyst. The Silver-Barium based catalytic materials of Ag (5 wt%-Ba(10 wt%/MO (MO=Al2O3, CeO2, ZrO2, and Ag (5 wt%-Sr (10 wt%/CeO2 catalysts have been prepared by wetness impregnation method and characterized by BET, XRD, HRTEM, XPS and TPR (temperature-programmed reduction experiments. The behavior of the catalyst in the soot combustion (under tight conditions and NOX elimination has been separately analyzed by means of temperature programmed oxidation and isothermal concentration step change experiments, respectively. The results showed that all the catalysts were active in soot combustion with an indicative decrease of oxidation onset temperature compared to uncatalyzed soot oxidation. The removal of NOX in the presence and in the absence of soot was investigated under cycling conditions, i.e. alternating lean-rich phases according to the LNT approach. It has been found that the Ag-based samples were able to simultaneously remove soot and NOX. In particular, studying the behavior of the prepared catalysts, the Ba-containing systems exhibited higher NOX storage capacity than Sr-catalyst; also, the nitrogen selectivity increased even if resulted lower than the traditional LNT Pt-based catalyst. An adverse effect of soot on the NOX storage activity has been also observed. Copyright © 2017 BCREC GROUP. All rights reserved Received: 18th August 2016; Revised: 19th October 2016; Accepted: 19th October 2016 How to Cite: Dhal, G.C., Dey, S., Prasad, R., Mohan, D. (2017. Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials. Bulletin of

  9. Crowdsourcing urban air temperature measurements using smartphones

    Science.gov (United States)

    Balcerak, Ernie

    2013-10-01

    Crowdsourced data from cell phone battery temperature sensors could be used to contribute to improved real-time, high-resolution air temperature estimates in urban areas, a new study shows. Temperature observations in cities are in some cases currently limited to a few weather stations, but there are millions of smartphone users in many cities. The batteries in cell phones have temperature sensors to avoid damage to the phone.

  10. Evaluation of a Lagrangian Soot Tracking Method for the prediction of primary soot particle size under engine-like conditions

    DEFF Research Database (Denmark)

    Cai Ong, Jiun; Pang, Kar Mun; Walther, Jens Honore

    2018-01-01

    particles when the mass of incipient soot exceeds a designated threshold value. Their trajectories are then computed using the particle momentum equation. The change of primary soot particle size is dependent on the modified Lagrangian surface growth and soot oxidation models. Performance of the LST model...

  11. Impact of intake CO 2 addition and exhaust gas recirculation on NO x emissions and soot reactivity in a common rail diesel engine

    KAUST Repository

    Al-Qurashi, Khalid

    2012-10-18

    The impact of intake CO 2 addition and exhaust gas recirculation (EGR) on engine combustion characteristics, NO x emissions, and soot oxidative reactivity was studied in a common rail diesel engine equipped with a cooled EGR system. The engine test results and the heat release analysis show that the reduced flame temperature, induced by the reduction of the oxygen concentration (dilution effect) is the dominant mechanism via which CO 2 and EGR lower NO x emissions in diesel engines. On the other hand, the collected soot from the engine tests was examined for its oxidative reactivity using a thermogravimetric analyzer (TGA). Results show that EGR has a significant effect on soot reactivity and results in higher initial active sites compared to the CO 2 case. We conclude that the reduced flame temperature (thermal effect) which is a consequence of the dilution effect is responsible for the observed increase in soot reactivity. These results confirm observations from our past work on flame soot, which showed that the peak adiabatic flame temperature is the governing factor affecting soot reactivity. These findings imply that driving the combustion concepts toward low temperature is favorable to effectively control engine pollutants, including soot reactivity. © 2012 American Chemical Society.

  12. Thermal and optical analysis of selective absorber coatings based on soot for applications in solar cookers

    Science.gov (United States)

    Servín, H.; Peña, M.; Sobral, H.; González, M.

    2017-01-01

    The thermal and optical properties of selective absorber coatings of a solar cooker have been investigated. Coatings have been prepared using soot from pine resin, wood stove and sugarcane, previously separated by size. Results show that the cooking power and the overall efficiency of these pots are higher than others painted with black primer. Besides, by using an integrating sphere, the diffuse reflectance of absorbers has been obtained. Lower values of the reflectance have been measured for the pots covered with soot, showing a high correlation with the results achieved from the thermal tests, considering the measurement errors.

  13. Simulation and analysis of the soot particle size distribution in a turbulent nonpremixed flame

    KAUST Repository

    Lucchesi, Marco

    2017-02-05

    A modeling framework based on Direct Simulation Monte Carlo (DSMC) is employed to simulate the evolution of the soot particle size distribution in turbulent sooting flames. The stochastic reactor describes the evolution of soot in fluid parcels following Lagrangian trajectories in a turbulent flow field. The trajectories are sampled from a Direct Numerical Simulation (DNS) of a n-heptane turbulent nonpremixed flame. The DSMC method is validated against experimentally measured size distributions in laminar premixed flames and found to reproduce quantitatively the experimental results, including the appearance of the second mode at large aggregate sizes and the presence of a trough at mobility diameters in the range 3–8 nm. The model is then applied to the simulation of soot formation and growth in simplified configurations featuring a constant concentration of soot precursors and the evolution of the size distribution in time is found to depend on the intensity of the nucleation rate. Higher nucleation rates lead to a higher peak in number density and to the size distribution attaining its second mode sooner. The ensemble-averaged PSDF in the turbulent flame is computed from individual samples of the PSDF from large sets of Lagrangian trajectories. This statistical measure is equivalent to time-averaged, scanning mobility particle size (SMPS) measurements in turbulent flames. Although individual trajectories display strong bimodality as in laminar flames, the ensemble-average PSDF possesses only one mode and a long, broad tail, which implies significant polydispersity induced by turbulence. Our results agree very well with SMPS measurements available in the literature. Conditioning on key features of the trajectory, such as mixture fraction or radial locations does not reduce the scatter in the size distributions and the ensemble-averaged PSDF remains broad. The results highlight and explain the important role of turbulence in broadening the size distribution of

  14. High-temperature archeointensity measurements from Mesopotamia

    Science.gov (United States)

    Gallet, Yves; Le Goff, Maxime

    2006-01-01

    We present new archeointensity results obtained from 127 potsherds and baked brick fragments dated from the last four millennia BC which were collected from different Syrian archeological excavations. High temperature magnetization measurements were carried out using a laboratory-built triaxial vibrating sample magnetometer (Triaxe), and ancient field intensity determinations were derived from the experimental procedure described by Le Goff and Gallet [Le Goff and Gallet. Earth Planet. Sci. Lett. 229 (2004) 31-43]. As some of the studied samples were previously analyzed using the classical Thellier and Thellier [Thellier and Thellier . Ann. Geophys. 15 (1959) 285-376] method revised by Coe [Coe. J. Geophys. Res. 72 (1967) 3247-3262], a comparison of the results is made from the two methods. The differences both at the fragment and site levels are mostly within ± 5%, which strengthens the validity of the experimental procedure developed for the Triaxe. The new data help to better constrain the geomagnetic field intensity variations in Mesopotamia during archeological times, with the probable occurrence of an archeomagnetic jerk around 2800-2600 BC.

  15. Two-Color Pyrometer for Process Temperature Measurement During Machining

    OpenAIRE

    Tapetado Moraleda, Alberto; Díaz Álvarez, José; Miguélez Garrido, María Henar; Vázquez García, María Carmen

    2016-01-01

    A fast fiber-optic two-color pyrometer operating on the optical communication bands is designed for temperature measurements in machining processes. Off-the-shelf low-loss fiber-optic demultiplexers and optoelectronics equipment are used in order to obtain a cost-effective sensing solution while reducing both the temperature measurement error and the minimum measurable temperature. The system is capable of measuring highly localized temperatures without using collimation lens. The designed py...

  16. Low temperature fiber optic pyrometer for fast time resolved temperature measurements

    Science.gov (United States)

    Willsch, M.; Bosselmann, T.; Gaenshirt, D.; Kaiser, J.; Villnow, M.; Banda, M.

    2016-05-01

    Low temperature Pyrometry at temperatures beyond 150°C is limited in the measurement speed due to slow pyroelectric detectors. To detect the circumferential temperature distribution of fast rotating machines a novel Fiber Optical Pyrometer Type is presented here.

  17. Cloud droplet activity changes of soot aerosol upon smog chamber ageing

    Science.gov (United States)

    Wittbom, C.; Eriksson, A. C.; Rissler, J.; Carlsson, J. E.; Roldin, P.; Nordin, E. Z.; Nilsson, P. T.; Swietlicki, E.; Pagels, J. H.; Svenningsson, B.

    2014-09-01

    parameters describing the organic material), showed good agreement with cloud droplet activation measurements for particles with a SOA mass fraction ≥0.12 (slightly aged particles). The activation properties are enhanced with only a slight increase in organic material coating the soot particles (SOA mass fraction < 0.12), however not as much as predicted by Köhler theory. The discrepancy between theory and experiments during the early stages of ageing might be due to solubility limitations, unevenly distributed organic material or hindering particle morphology. The change in properties of soot nanoparticles upon photochemical processing clearly increases their hygroscopicity, which affects their behaviour both in the atmosphere and in the human respiratory system.

  18. Chinese Soot on a Vietnamese Soup

    Science.gov (United States)

    Mari, X.

    2015-12-01

    Black Carbon (BC) is an aerosol emitted as soot during biomass burning and fossil fuels combustion together with other carbonaceous aerosols such as organic carbon (OC) and polyaromatic hydrocarbons (PAHs). While the impacts of BC on health and climate have been studied for many years, studies about its deposition and impact on marine ecosystems are scares. This is rather surprising considering that a large fraction of atmospheric BC deposits on the surface of the ocean via dry or wet deposition. On a global scale, deposition on the ocean is about 45 Tg C per year, with higher fluxes in the northern hemisphere and in inter-tropical regions, following the occurrence of the hot-spots of concentration. In the present study conducted on shore, in Haiphong and Halong cities, North Vietnam, we measured the seasonal variations of atmospheric BC, OC and PAHs during a complete annual cycle. The presentation will discuss the atmospheric results in terms of seasonal variability and sources. Inputs to the marine system are higher during the dry season, concomitantly with the arrival of air masses enriched in BC coming from the North. However, the carbon fingerprint can significantly differ at shorter time periods depending on the air mass pathway and speed. Our work leads to the characterization and the determination of the relative contribution of more specific sources like local traffic, which includes tourism and fishing boats, coal dust emitted from the nearby mine, and long-range transported aerosols. This variable input of carbonaceous aerosols might have consequences for the cycling and the repartition of carbon and nutrients in the marine ecosystem of Halong Bay.

  19. Bulk temperature measurement in thermally striped pipe flows

    International Nuclear Information System (INIS)

    Lemure, N.; Olvera, J.R.; Ruggles, A.E.

    1995-12-01

    The hot leg flows in some Pressurized Water Reactor (PWR) designs have a temperature distribution across the pipe cross-section. This condition is often referred to as a thermally striped flow. Here, the bulk temperature measurement of pipe flows with thermal striping is explored. An experiment is conducted to examine the feasibility of using temperature measurements on the external surface of the pipe to estimate the bulk temperature of the flow. Simple mixing models are used to characterize the development of the temperature profile in the flow. Simple averaging techniques and Backward Propagating Neural Net are used to predict bulk temperature from the external temperature measurements. Accurate bulk temperatures can be predicted. However, some temperature distributions in the flow effectively mask the bulk temperature from the wall and cause significant error in the bulk temperature predicted using this technique

  20. Soot formation of lignin derived fuels in a laminar co-flow diffusion flame

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, P.A.M.

    2009-07-15

    Due to limited fossil fuels reserves and increasing CO2 and soot concentration in the atmosphere, other cleaner fuels are needed. Use of biomass waste for the production of second generation bio-fuels might lead to a reduction of CO2 emissions. Second generation bio-fuels from biomass waste do not compete with food stock markets. Although limited available per unit time, biomass waste will be produced for ever. Therefore this resource is sustainable. Research on sooting tendency of different types of fuels is needed to find low sooting fuels which decrease air pollution, thereby killing two birds with one stone. Current research investigated sooting tendencies of possible biofuels from lignin. Lignin is a biopolymer which accounts for 15-30 wt.% of woody biomass. Besides lignin, woody biomass consists of mainly cellulose and hemicellulose. Lignin is responsible for mechanical support of the plant, water conduction and protection against biodegradation. A method was searched to assign a value to a fuel which corresponds to the sooting tendency of that fuel. The method should be validated with Threshold Sooting Index (TSI) and Yield Sooting Index (YSI). The former is an aviation fuel testing method based on smoke point height while the latter is a recently developed method which measures soot concentrations using LII, both using laminar diffusion flames. In the current investigation sooting tendency was measured using line-of-sight attenuation in combination with inverse Abel transformation to determine the spatially resolved soot volume fraction. Different concentrations of test fuel (acetone, ethanol, cyclohexene, cyclohexanone, methane and toluene) mixed with base fuel (33,3 wt.% toluene and 66,7 wt.% n-heptane) were investigated. To enable rapid fuel changing a new fuel accumulator system was designed. In this system a syringe with a small amount of test fuel can easily be placed. Therefore no cleaning of the fuel accumulator is required since the syringes are

  1. Abatement of diesel-exhaust pollutants. NO{sub x} storage and soot combustion on K/La{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Milt, V.G.; Pissarello, M.L.; Miro, E.E.; Querini, C.A. [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE, CONICET, Santiago del Estero 2829, Santa Fe 3000 (Argentina)

    2003-03-31

    Potassium-loaded lanthana is a promising catalyst to be used for the simultaneous abatement of soot and NO{sub x}, which are the main diesel-exhaust pollutants. With potassium loadings between 4.5 and 10wt.% and calcination temperatures between 400 and 700C, this catalyst mixed with soot gave maximum combustion rates between 350 and 400C in TPO experiments, showing a good hydrothermal stability. There was no difference in activity when it was either mixed by grinding in an agate mortar or mixed by shaking in a sample bottle (tight and loose conditions, respectively). Moreover, when the K-loaded La{sub 2}O{sub 3} is used as washcoat for a cordierite monolith, there were found no significant differences in the catalytic behaviour of the system, which implies its potentiality for practical purposes. The influence of poisons as water and SO{sub 2} was investigated. While water does not affect the soot combustion activity, SO{sub 2} slightly shift the TPO peak to higher temperature. Surface basicity, which is a key factor, was analysed by measuring the interactions of the catalytic surface with CO{sub 2} using the high frequency CO{sub 2} pulses technique, which proved to be very sensitive, detecting minor changes by modifications in the dynamics of the CO{sub 2} adsorption-desorption process. Water diminishes the interaction with CO{sub 2}, probably as a consequence of an adsorption competition. The SO{sub 2} treated catalyst is equilibrated with the CO{sub 2} atmosphere more rapidly if compared with the untreated one, also showing a lower interaction. The lower the interaction with the CO{sub 2}, the lower the activity. Differential scanning calorimetric (DSC) results indicate that the soot combustion reaction coexists with the thermal decomposition of hydroxide and carbonate species, occurring in the same temperature range (350-460C). The presence of potassium increases surface basicity shifting the endothermic decomposition signal to higher temperatures. We also

  2. 7 CFR 28.301 - Measurement: humidity; temperature.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Measurement: humidity; temperature. 28.301 Section 28... for Length of Staple § 28.301 Measurement: humidity; temperature. The length of staple of any cotton... its fibers under a relative humidity of the atmosphere of 65 percent and a temperature of 70° F. ...

  3. Application of digital holography in temperature distribution measurement

    Science.gov (United States)

    Wang, Guangjun; Li, Yan; Wang, Dayong; Zhao, Jie

    2010-11-01

    A reflection heat source including a radiator as well as an aluminum plate is designed, and the temperature field of the aluminum plate is used as the tested object. The reflection lensless Fourier transform (LFT) digital holography is performed to measure the temperature field distribution. For the comparison, the temperature measurement system within the radiator is used to measure the temperature distributions. The results obtained by these two methods are in good agreement, which demonstrates that the digital holography method is valid for the measurement of the temperature distribution.

  4. On the Response of Nascent Soot Nanostructure and Oxidative Reactivity to Photoflash Exposure

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2017-07-01

    Full Text Available Soot particles are a kind of major pollutant from fuel combustion. To enrich the understanding of soot, this work focuses on investigating detailed influences of instantaneous external irradiation (conventional photoflash exposure on nanostructure as well as oxidation reactivity of nascent soot particles. By detailed soot characterizations flash can reduce the mass of soot and soot nanostructure can be reconstructed substantially without burning. After flash, the degree of soot crystallization increases while the soot reactive rate decreases and the activation energy increases. In addition, nanostructure and oxidative reactivity of soot in air and Ar after flash are different due to their different thermal conductivities.

  5. Measuring the temperature of hot nuclear fragments

    International Nuclear Information System (INIS)

    Wuenschel, S.; Bonasera, A.; May, L.W.; Souliotis, G.A.; Tripathi, R.; Galanopoulos, S.; Kohley, Z.; Hagel, K.; Shetty, D.V.; Huseman, K.; Soisson, S.N.; Stein, B.C.; Yennello, S.J.

    2010-01-01

    A new thermometer based on fragment momentum fluctuations is presented. This thermometer exhibited residual contamination from the collective motion of the fragments along the beam axis. For this reason, the transverse direction has been explored. Additionally, a mass dependence was observed for this thermometer. This mass dependence may be the result of the Fermi momentum of nucleons or the different properties of the fragments (binding energy, spin, etc.) which might be more sensitive to different densities and temperatures of the exploding fragments. We expect some of these aspects to be smaller for protons (and/or neutrons); consequently, the proton transverse momentum fluctuations were used to investigate the temperature dependence of the source.

  6. Numerical Computation of Optical Properties of Internally Mixed Soot in Biomass Burning Constrained by Field and Laboratory Observations

    Science.gov (United States)

    China, S.; Scarnato, B. V.; Gorkowski, K.; Aiken, A. C.; Liu, S.; Dubey, M. K.; Mazzoleni, C.

    2014-12-01

    Carbonaceous aerosol emitted from biomass burning (BB) contributes significantly to atmospheric aerosol loadings regionally and globally. Direct radiative forcing of BB aerosol is highly uncertain due to its complex composition, morphology and mixing state. Soot particles are the strongest light absorbing aerosols in BB smoke. In BB smoke, soot particles are normally internally mixed with other material and the mixing state can affect their optical properties. In this study we investigated morphology and mixing state of soot particles emitted from BB smoke from field and laboratory measurements. Smoke particles were collected 1) during the Las Conchas wildfire in New Mexico (June, 2011) and 2) at the U.S. Forest Service's Fire Science Laboratory in 2012, during the fourth Fire Laboratory at Missoula Experiment (FLAME-4). Single particles were analyzed with electron microscopy, and were categorized and characterized by their morphology, and mixing state. We found that soot particles were mostly heavily coated. Based on the characterization on field and laboratory samples, synthetic soot particles with various morphologies and mixing states were generated and their optical properties were numerically calculated using the discrete dipole approximation. We used organic material as a coating agent and investigated the spectral dependency of scattering and absorption for internally mixed soot particles. We found enhancement in scattering and absorption when most of the soot particle was embedded within the organic coating. The aim of this study is to improve our understanding of the effect of morphology and mixing on light scattering and absorption by soot particles and ultimately their effects on the direct radiative forcing.

  7. Temperature measurements on a HSLA-100 steel confinement vessel

    Energy Technology Data Exchange (ETDEWEB)

    Lohsen, R.A.

    1998-05-07

    Temperature measurements have been made on HSLA-100 steel confinement vessel number 6-2-3-1. These measurements are intended to give a view of the vessel temperature response under conditions similar to operational conditions, starting from worst case. The vessel`s temperature must be above the minimum operating temperature when used to contain an explosive event to ensure that the vessel material has the desired crack arrest properties. Several series of temperature measurements have been conducted over 24 and 48 hour periods during February 1998. These tests were intended to demonstrate that after running the heaters in the environmental shelter for some time, (1) the vessel warms up to temperatures well above the minimum operating temperature, (2) that through-thickness temperature gradients are negligible, and (3) that the temperature differences from one part of the vessel to another are small.

  8. Low Temperature Hall Measurements of Neutron Irradiated Silicon Carbide

    National Research Council Canada - National Science Library

    Bonavita, Ange1o

    2004-01-01

    .... No features suggesting annealing were found below a temperature of 340K. Temperature dependant Hall effect measurements were taken over a range of 100K to 340K recording resistivity, carrier densities, and mobility...

  9. Isothermal temperature reactivity coefficient measurement in TRIGA reactor

    International Nuclear Information System (INIS)

    Zagar, T.; Ravnik, M.; Trkov, A.

    2002-01-01

    Direct measurement of an isothermal temperature reactivity coefficient at room temperatures in TRIGA Mark II research reactor at Jozef Stefan Institute in Ljubljana is presented. Temperature reactivity coefficient was measured in the temperature range between 15 o C and 25 o C. All reactivity measurements were performed at almost zero reactor power to reduce or completely eliminate nuclear heating. Slow and steady temperature decrease was controlled using the reactor tank cooling system. In this way the temperatures of fuel, of moderator and of coolant were kept in equilibrium throughout the measurements. It was found out that TRIGA reactor core loaded with standard fuel elements with stainless steel cladding has small positive isothermal temperature reactivity coefficient in this temperature range.(author)

  10. Investigation of temperature correction for tire/pavement noise measurements

    Science.gov (United States)

    2010-11-01

    The Volpe Center Acoustics Facility, in support of the Federal Highway Administration, : investigated the influence of temperature on tire/pavement noise in order to provide guidance on correcting for temperature variations in measured sound levels. ...

  11. Experimental relations between airborne and ground measured wheat canopy temperatures

    Science.gov (United States)

    Millard, J. P.; Reginato, R. J.; Idso, S. B.; Jackson, R. D.; Goettelman, R. C.; Leroy, M. J.

    1980-01-01

    Experiments using ground-based measurements of canopy temperatures have shown that plant temperatures are good indicators of plant water stress, and thus are useful for assessing water requirements and predicting yields. An intensive 23-day airborne- and ground-measurement program was conducted in Phoenix, Arizona in 1977 to compare airborne-acquired wheat canopy temperatures with simultaneous ground measurements. For canopies that covered at least 85 percent of the soil surface, airborne measurements differed from ground measurements of plant temperature by less than 2 C. Regardless of the amount of plant cover, the airborne measurements were virtually identical to ground-nadir measurements, and thus represent a combination of plant temperature and solid background temperature.

  12. Investigation of soot by two-color four-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B.; Stampanoni-Panariello, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    A novel, non-intrusive technique has been used for the temporally resolved investigation of the interaction of laser radiation and soot in a flame. While there is a fairly good agreement between measurement and simulation remaining discrepancies indicate some shortcomings of the model employed. (author) 2 figs., 2 refs.

  13. Electron Density and Temperature Measurements, and Abundance ...

    Indian Academy of Sciences (India)

    tribpo

    tics—emission lines. Dwivedi, Curdt & Wilhelm (1997, 1999a) carried out an observing sequence based on a theoretical study by Dwivedi & Mohan (1995), with intercombination/forbidden. Ne VI and Mg VI lines, which are formed at essentially the same temperature. (4 × 105 K), according to Arnaud & Rothenflug (1985).

  14. Multidimensional Simulation of NO and Soot from D.I. Diesel Engines with Fuel Injection Rate Shaping

    Science.gov (United States)

    Yamane, Koji; Shimamoto, Yuzuru

    The multidimensional engine simulation code, FREC-3D(CI), has been used to elucidate the effects of injection rate and split injection on diesel combustion, NO, and soot emissions. The combustion submodel has been updated, including the ignition submodel previously based on a one-step global mechanism. In-cylinder NO and soot formations were predicted by a Zeldovich mechanism with a partial equilibrium assumption and Morel’s soot formation with an oxidation submodel, respectively. In result, computations give good agreement between measured and predicted trends of in-cylinder pressure, and rate of heat release, and a trade-off relationship between NO and soot emissions at pilot injection with high pressure injection. Computations also show that a high turbulence kinetic energy caused by a higher initial combustion is retained at the late combustion stage after fuel injection, and promotes the soot oxidation process. Predictions made with split injection suggest that a combination of high pressure injection in conjunction with a short period in second pulse is effective to reduce soot emission.

  15. Nanosecond-resolved temperature measurements using magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wenbiao; Zhang, Pu [School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Wenzhong, E-mail: lwz7410@hust.edu.cn [School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China); Key Laboratory of Image Processing and Intelligent Control, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-05-15

    Instantaneous and noninvasive temperature measurements are important when laser thermotherapy or welding is performed. A noninvasive nanosecond-resolved magnetic nanoparticle (MNP) temperature measurement system is described in which a transient change in temperature causes an instantaneous change in the magnetic susceptibilities of the MNPs. These transient changes in the magnetic susceptibilities are rapidly recorded using a wideband magnetic measurement system with an upper frequency limit of 0.5 GHz. The Langevin function (the thermodynamic model characterizing the MNP magnetization process) is used to obtain the temperature information. Experiments showed that the MNP DC magnetization temperature-measurement system can detect a 14.4 ns laser pulse at least. This method of measuring temperature is likely to be useful for acquiring the internal temperatures of materials irradiated with lasers, as well as in other areas of research.

  16. Nanosecond-resolved temperature measurements using magnetic nanoparticles

    Science.gov (United States)

    Xu, Wenbiao; Liu, Wenzhong; Zhang, Pu

    2016-05-01

    Instantaneous and noninvasive temperature measurements are important when laser thermotherapy or welding is performed. A noninvasive nanosecond-resolved magnetic nanoparticle (MNP) temperature measurement system is described in which a transient change in temperature causes an instantaneous change in the magnetic susceptibilities of the MNPs. These transient changes in the magnetic susceptibilities are rapidly recorded using a wideband magnetic measurement system with an upper frequency limit of 0.5 GHz. The Langevin function (the thermodynamic model characterizing the MNP magnetization process) is used to obtain the temperature information. Experiments showed that the MNP DC magnetization temperature-measurement system can detect a 14.4 ns laser pulse at least. This method of measuring temperature is likely to be useful for acquiring the internal temperatures of materials irradiated with lasers, as well as in other areas of research.

  17. Empirical soot formation and oxidation model

    Directory of Open Access Journals (Sweden)

    Boussouara Karima

    2009-01-01

    Full Text Available Modelling internal combustion engines can be made following different approaches, depending on the type of problem to be simulated. A diesel combustion model has been developed and implemented in a full cycle simulation of a combustion, model accounts for transient fuel spray evolution, fuel-air mixing, ignition, combustion, and soot pollutant formation. The models of turbulent combustion of diffusion flame, apply to diffusion flames, which one meets in industry, typically in the diesel engines particulate emission represents one of the most deleterious pollutants generated during diesel combustion. Stringent standards on particulate emission along with specific emphasis on size of emitted particulates have resulted in increased interest in fundamental understanding of the mechanisms of soot particulate formation and oxidation in internal combustion engines. A phenomenological numerical model which can predict the particle size distribution of the soot emitted will be very useful in explaining the above observed results and will also be of use to develop better particulate control techniques. A diesel engine chosen for simulation is a version of the Caterpillar 3406. We are interested in employing a standard finite-volume computational fluid dynamics code, KIVA3V-RELEASE2.

  18. Temperature Measurement and Numerical Prediction in Machining Inconel 718.

    Science.gov (United States)

    Díaz-Álvarez, José; Tapetado, Alberto; Vázquez, Carmen; Miguélez, Henar

    2017-06-30

    Thermal issues are critical when machining Ni-based superalloy components designed for high temperature applications. The low thermal conductivity and extreme strain hardening of this family of materials results in elevated temperatures around the cutting area. This elevated temperature could lead to machining-induced damage such as phase changes and residual stresses, resulting in reduced service life of the component. Measurement of temperature during machining is crucial in order to control the cutting process, avoiding workpiece damage. On the other hand, the development of predictive tools based on numerical models helps in the definition of machining processes and the obtainment of difficult to measure parameters such as the penetration of the heated layer. However, the validation of numerical models strongly depends on the accurate measurement of physical parameters such as temperature, ensuring the calibration of the model. This paper focuses on the measurement and prediction of temperature during the machining of Ni-based superalloys. The temperature sensor was based on a fiber-optic two-color pyrometer developed for localized temperature measurements in turning of Inconel 718. The sensor is capable of measuring temperature in the range of 250 to 1200 °C. Temperature evolution is recorded in a lathe at different feed rates and cutting speeds. Measurements were used to calibrate a simplified numerical model for prediction of temperature fields during turning.

  19. Temperature Measurement and Numerical Prediction in Machining Inconel 718

    Science.gov (United States)

    Tapetado, Alberto; Vázquez, Carmen; Miguélez, Henar

    2017-01-01

    Thermal issues are critical when machining Ni-based superalloy components designed for high temperature applications. The low thermal conductivity and extreme strain hardening of this family of materials results in elevated temperatures around the cutting area. This elevated temperature could lead to machining-induced damage such as phase changes and residual stresses, resulting in reduced service life of the component. Measurement of temperature during machining is crucial in order to control the cutting process, avoiding workpiece damage. On the other hand, the development of predictive tools based on numerical models helps in the definition of machining processes and the obtainment of difficult to measure parameters such as the penetration of the heated layer. However, the validation of numerical models strongly depends on the accurate measurement of physical parameters such as temperature, ensuring the calibration of the model. This paper focuses on the measurement and prediction of temperature during the machining of Ni-based superalloys. The temperature sensor was based on a fiber-optic two-color pyrometer developed for localized temperature measurements in turning of Inconel 718. The sensor is capable of measuring temperature in the range of 250 to 1200 °C. Temperature evolution is recorded in a lathe at different feed rates and cutting speeds. Measurements were used to calibrate a simplified numerical model for prediction of temperature fields during turning. PMID:28665312

  20. Effects of externally-through-internally-mixed soot inclusions within clouds and precipitation on global climate.

    Science.gov (United States)

    Jacobson, Mark Z

    2006-06-01

    This paper examines the incremental global climate response of black carbon (BC), the main component of soot, due to absorption and scattering by BC inclusions within cloud and precipitation particles. Modeled soot is emitted as an externally mixed aerosol particle. It evolves to an internal mixture through condensation, hydration, dissolution, dissociation, crystallization, aqueous chemistry, coagulation, and cloud processing. Size-resolved cloud liquid and ice particles grow by condensation onto size-resolved soot and other particles. Cloud particles grow to precipitation by coagulation and the Bergeron process. Cloud and precipitation particles also undergo freezing, melting, evaporation, sublimation, and coagulation with interstitial aerosol particles. Soot, which is tracked in cloud and precipitation particles of all sizes, is removed by rainout, washout, sedimentation, and dry deposition. Two methods of treating the optics of BC in size-resolved cloud liquid, ice and graupel are compared: the core-shell approximation (CSA) and the iterative dynamic effective medium approximation (DEMA). The 10-year global near-surface incremental temperature response due to fossil fuel (ff), biofuel (bf), and biomass burning (bb) BC within clouds with the DEMA was slightly stronger than that with the CSA, but both enhancements were clouds may enhance the near-surface temperature response of ff+bf soot due to all processes (estimated as approximately 0.27 K), by climate impact of BC. BC cloud absorption was also found to increase water vapor, decrease precipitation, and decrease cloud fraction. The increase in water vapor at the expense of precipitation contributed to warming in addition to that of the cloud BC absorption itself. Aerosol-hydrometeor coagulation followed by hydrometeor evaporation may have caused almost twice the BC internal mixing as aerosol-aerosol coagulation.

  1. Cryogenic temperature measurement for large applications

    CERN Document Server

    Ylöstalo, J; Kyynäräinen, J; Niinikoski, T O; Voutilainen, R

    1996-01-01

    We have developed a resistance thermometry system for the acquisition, control and monitoring of temperature in large-scale cryogenic applications. The resistance of the sensor is converted to a voltage using a self-balancing AC bridge circuit featuring square-wave excitation currents down to 1 nA. The system is easily scalable and includes intelligent features to treat special situations such as magnet quenches differently from normal operation.

  2. Design and Implementation of High Precision Temperature Measurement Unit

    Science.gov (United States)

    Zeng, Xianzhen; Yu, Weiyu; Zhang, Zhijian; Liu, Hancheng

    2018-03-01

    Large-scale neutrino detector requires calibration of photomultiplier tubes (PMT) and electronic system in the detector, performed by plotting the calibration source with a group of designated coordinates in the acrylic sphere. Where the calibration source positioning is based on the principle of ultrasonic ranging, the transmission speed of ultrasonic in liquid scintillator of acrylic sphere is related to temperature. This paper presents a temperature measurement unit based on STM32L031 and single-line bus digital temperature sensor TSic506. The measurement data of the temperature measurement unit can help the ultrasonic ranging to be more accurate. The test results show that the temperature measurement error is within ±0.1°C, which satisfies the requirement of calibration source positioning. Take energy-saving measures, with 3.7V/50mAH lithium battery-powered, the temperature measurement unit can work continuously more than 24 hours.

  3. ATTREX-Aircraft_RemoteSensing_Temperature_Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — This collection consists of the observational data from the Airborne Tropical TRopopause EXperiment (ATTREX) spectral and broad band irradiance measurements covering...

  4. Nonequilibrium shock layer temperature profiles from arc jet radiation measurements

    Science.gov (United States)

    Blackwell, Harvel E.; Yuen, Eric; Scott, Carl D.; Arepalli, Sivaram

    1989-01-01

    Shock layer temperature profiles are obtained through analysis of radiation from shock layers produced by a blunt body inserted in arc jet flow. Spectral measurements have been made in a nitrogen flow of 54.4 gm/s at an enthalpy of 8.72 MJ/kg. Vibrational temperatures for N2+ are obtained by matching spectral regions from arc jet spectra with spectra generated using the NEQAIR code. Temperature profiles obtained from the radiation layers show a vibrational temperature higher than the rotational temperature near the front of the shock and both temperatures decrease as the flow approaches the body. The spectral measurements are made and analysis completed for four distances, from the surface of the blunt body. The corresponding shock layer thickness is approximately 3.6 cm. Although the shock layer appears to be in thermal nonequilibrium, the measured rotational temperature approaches the single temperature results of viscous shock layer calculations at this test condition.

  5. The liner brightness temperature measurement by two channel optical pyrometer

    Science.gov (United States)

    Kulish, M. I.; Dudin, S. V.; Ushnurtsev, A. E.; Mintsev, V. B.

    2018-01-01

    Measurability of liner inner surface brightness temperature by two channel optical pyrometer is shown. Liner is compressed by detonation products in large-scale experiment. Absolute radiant intensity values were obtained by measuring optical system channel calibration involving tungsten and xenon radiation sources. Three ways of surface brightness temperature measurement are presented at wavelengths of 620 and 850 nm. Using the developed procedure copper and steel liners behavior (brightness temperature, average speed) under compression by detonation products are evaluated.

  6. Temperature Measurement of a Glass Material Using a Multiwavelength Pyrometer

    Science.gov (United States)

    Ng, Daniel

    1997-01-01

    Temperature measurement of a substance that is transparent using the traditional 1-color, 2-color and other pyrometers has been difficult. The radiation detected by pyrometers do not come from a well defined location in the transparent body. The multiwavelength pyrometer developed at the NASA Lewis Research Center can measure the surface temperature of many materials. We show in this paper that it also measures the surface and a bulk subsurface temperature of transparent materials like glass.

  7. Solar energy control system. [temperature measurement

    Science.gov (United States)

    Currie, J. R. (Inventor)

    1981-01-01

    A solar energy control system for a hot air type solar energy heating system wherein thermocouples are arranged to sense the temperature of a solar collector, a space to be heated, and a top and bottom of a heat storage unit is disclosed. Pertinent thermocouples are differentially connected together, and these are employed to effect the operation of dampers, a fan, and an auxiliary heat source. In accomplishing this, the differential outputs from the thermocouples are amplified by a single amplifier by multiplexing techniques. Additionally, the amplifier is corrected as to offset by including as one multiplex channel a common reference signal.

  8. Changes in radiative properties of soot contaminated maize canopy

    Science.gov (United States)

    Illes, B.; Anda, A.

    2012-04-01

    The effect of particle (Black Carbon, BC) on certain radiative characteristics of maize plants was studied over 2011 growing season in a field experiment carried out in Keszthely Agrometeorological Research Station. As the main constituent of BC, the soot that is almost exclusively responsible for light absorption by particles in the atmosphere, thus changing the radiation balance of the Earth and contributing to global warming. Maize hybrid Perlona (FAO 340) with short-season was applied as test plant. Of the two water supply treatments, the rainfed variant was sown in field plots, while compensation evapotranspirometers of the Thornthwaite type were used for the "ad libitum" treatment. The BC applied as pollutant was coming from the Hankook Tyre Company (Dunaújváros, Hungary), where it is used to improve the wear resistance of the tyres. The black carbon was chemically "pure", i.e. it is free of other contaminants (heavy metals etc.), so the reproducibility of the experiment is not problematic, unlike that of tests on other atmospheric air pollutants. Road traffic was simulated by using frequent low particle rates (3 g m-2 week-1) with a motorised sprayer of SP 415 type, during the season. The leaf area index was measured each week on the same 12 sample plants in each treatment using an LI 3000A automatic planimeter (LI-COR, Lincoln, NE). The impact of black carbon on plant radiative properties were analysed in the field (about 0.3 ha/treatment). Pyranometers of the CMA-11 type (Kipp & Zonen, Vaisala) were installed on columns of adjustable height in the centre of the 0.3 ha plots designated for albedo measurements. Data were collected using a Logbox SD (Kipp & Zonen, Vaisala) datalogger in the form of 10-minute means of samples taken every 6 seconds. BC pollution had no effect on maize growth and development. Compared with soot contaminated and control plants, we concluded that the LAI was a few percent higher in polluted plants, but this increment was not

  9. Device for the alternative option of temperature measurement

    Science.gov (United States)

    Jargus, Jan; Nedoma, Jan; Fajkus, Marcel; Novak, Martin; Cubik, Jakub; Cvejn, Daniel; Vasinek, Vladimir

    2017-10-01

    Polydimethylsiloxane (PDMS) has good optical properties, and its composition offers the possibility of use in many applications (industry, security device, medicine applications and etc.). We focused on the alternative option of temperature measurement in this article. Our approach is based on measuring changes of chromaticity correlated temperature corresponding to changes in temperature. Described device uses an optical fiber with a defined layer of PDMS and luminophore and we assume that it can find use also in the field of security. The article describes the process of making the prototype of the device and its verification based on laboratory results. The measured temperature depends mainly on the type of optical fiber and the measured temperature range is determined by the thermal resistance of used optical fiber. Using a calibration measurement can determine the value of temperature with an accuracy of +/- 2,5 %.

  10. Temperature Measurement of Ceramic Materials Using a Multiwavelength Pyrometer

    Science.gov (United States)

    Ng, Daniel; Fralick, Gustave

    1999-01-01

    The surface temperatures of several pure ceramic materials (alumina, beryllia, magnesia, yittria and spinel) in the shape of pellets were measured using a multiwavelength pyrometer. In one of the measurements, radiation signal collection is provided simply by an optical fiber. In the other experiments, a 4.75 inch (12 cm) parabolic mirror collects the signal for the spectrometer. Temperature measurement using the traditional one- and two-color pyrometer for these ceramic materials is difficult because of their complex optical properties, such as low emissivity which varies with both temperature and wavelength. In at least one of the materials, yittria, the detected optical emission increased as the temperature was decreased due to such emissivity variation. The reasons for such changes are not known. The multiwavelength pyrometer has demonstrated its ability to measure surface temperatures under such conditions. Platinum electrodes were embedded in the ceramic pellets for resistance measurements as the temperature changed.

  11. LIDAR for atmospheric backscatter and temperature measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to demonstrate key capabilities of a multifunctional atmospheric lidar. This lidar could be part of a Surface Weather Station to measure atmospheric...

  12. Measurement of magnetic properties at cryogenic temperatures

    CERN Multimedia

    1977-01-01

    This picture shows part of the low-mu permeameter to measure permeability of stainless steels and other low-mu materials used in superconducting magnets. The sample, a 5 mm diam., 45 mm long rod, is suspended to long leads before being inserted in the test cryostat. For the measurement the sample is surrounded by a flux- measuring coil and placed in the field of a superconducting solenoid. At a given field the sample is removed.During the removal, the voltage induced in the flux-measuring coil is time integrated giving the flux variation. This equipment was developed to select stainless steels and other low-mu materials used in the ISR Prototype Superconducting Qaudrupole. The person is W.Ansorge.

  13. Effective density of Aquadag and fullerene soot black carbon reference materials used for SP2 calibration

    Directory of Open Access Journals (Sweden)

    M. Gysel

    2011-12-01

    Full Text Available The mass and effective density of black carbon (BC particles generated from aqueous suspensions of Aquadag and fullerene soot was measured and parametrized as a function of their mobility diameter. The measurements were made by two independent research groups by operating a differential mobility analyser (DMA in series with an aerosol particle mass analyser (APM or a Couette centrifugal particle mass analyser (CPMA. Consistent and reproducible results were found in this study for different production lots of Aquadag, indicating that the effective density of these particles is a stable quantity and largely unaffected by differences in aerosol generation procedures and suspension treatments. The effective density of fullerene soot particles from one production lot was also found to be stable and independent of suspension treatments. Some differences to previous literature data were observed for both Aquadag and fullerene soot at larger particle diameters. Knowledge of the exact relationship between mobility diameter and particle mass is of great importance, as DMAs are commonly used to size-select particles from BC reference materials for calibration of single particle soot photometers (SP2, which quantitatively detect the BC mass in single particles.

  14. Influence of Sensor Ingestion Timing on Consistency of Temperature Measures

    National Research Council Canada - National Science Library

    Goodman, Daniel A; Kenefick, Robert W; Cadarette, Bruce S; Cheuvront, Samuel N

    2009-01-01

    ... (ITS) to measure core body temperature have been demonstrated. However, the effect of elapsed time between ITS ingestion and Tint measurement has not been thoroughly studied. Methods: Eight volunteers...

  15. Measurement of temperature fluctuations and anomalous transport ...

    Indian Academy of Sciences (India)

    (b) Displacement of plasma from the centre of the vacuum vessel; horizontal displacement ¡А ( ve means ... vacuum vessel) and the ion saturation current Б× drawn by the pair is obtained by measur- ing the voltage drop ... sheared E- xB rotation (plasma rotation) as observed in other machines [8]. The fluctuation induced ...

  16. Upgrade of the cooling water temperature measures system for HLS

    International Nuclear Information System (INIS)

    Guo Weiqun; Liu Gongfa; Bao Xun; Jiang Siyuan; Li Weimin; He Duohui

    2007-01-01

    The cooling water temperature measures system for HLS (Hefei Light Source) adopts EPICS to the developing platform and takes the intelligence temperature cruise instrument for the front control instrument. Data of temperatures are required by IOCs through Serial Port Communication, archived and searched by Channel Archiver. The system can monitor the real-time temperatures of many channels cooling water and has the function of history data storage, and data network search. (authors)

  17. Development of electron temperature measuring system by silicon drift detector

    International Nuclear Information System (INIS)

    Song Xianying; Yang Jinwei; Liao Min

    2007-12-01

    Soft X-ray spectroscopy with two channels Silicon Drift Detector (SDD) are adopted for electron temperature measuring on HL-2A tokamak in 2005. The working principle, design and first operation of the SDD soft X-ray spectroscopy are introduced. The measuring results of electron temperature are also presented. The results show that the SDD is very good detector for electron temperature measuring on HL-2A tokamak. These will become a solid basic work to establish SDD array for electron temperature profiling. (authors)

  18. MPPT Technique Based on Current and Temperature Measurements

    OpenAIRE

    Vicente, Eduardo Moreira; Moreno, Robson Luiz; Ribeiro, Enio Roberto

    2015-01-01

    This paper presents a new maximum power point tracking (MPPT) method based on the measurement of temperature and short-circuit current, in a simple and efficient approach. These measurements, which can precisely define the maximum power point (MPP), have not been used together in other existing techniques. The temperature is measured with a low cost sensor and the solar irradiance is estimated through the relationship of the measured short-circuit current and its reference. Fast tracking spee...

  19. Measurement of relative permittivity of LTCC ceramic at different temperatures

    Science.gov (United States)

    Tan, Qiulin; Kang, Hao; Qin, Li; Xiong, Jijun; Zhou, Zhaoying; Zhang, Wendong; Luo, Tao; Xue, Chenyang; Liu, Jun

    2014-03-01

    Devices based on LTCC (low-temperature co-fired ceramic) technology are more widely applied in high temperature environments, and the temperature-dependent properties of the LTCC material play an important role in measurements of the characteristics of these devices at high temperature. In this paper, the temperature-dependence of the relative permittivity of DuPont 951 LTCC ceramic is studied from room temperature to 500 °C. An expression for relative permittivity is obtained, which relates the relative permittivity to the resonant frequency, inductance, parasitic capacitance and electrode capacitance of the LTCC sample. Of these properties, the electrode capacitance is the most strongly temperature-dependent. The LTCC sample resonant frequency, inductance and parasitic capacitance were measured (from room temperature to 500 °C) with a high temperature measurement system comprising a muffle furnace and network analyzer. We found that the resonant frequency reduced and the inductance and parasitic capacitance increased slightly as the temperature increases. The relative permittivity can be calculated from experimental frequency, inductance and parasitic capacitance measurements. Calculating results show that the relative permittivity of DuPont 951 LTCC ceramic ceramic increases to 8.21 from room temperature to 500 °C.

  20. Measurement of relative permittivity of LTCC ceramic at different temperatures

    Directory of Open Access Journals (Sweden)

    Qiulin Tan

    2014-02-01

    Full Text Available Devices based on LTCC (low-temperature co-fired ceramic technology are more widely applied in high temperature environments, and the temperature-dependent properties of the LTCC material play an important role in measurements of the characteristics of these devices at high temperature. In this paper, the temperature-dependence of the relative permittivity of DuPont 951 LTCC ceramic is studied from room temperature to 500 °C. An expression for relative permittivity is obtained, which relates the relative permittivity to the resonant frequency, inductance, parasitic capacitance and electrode capacitance of the LTCC sample. Of these properties, the electrode capacitance is the most strongly temperature-dependent. The LTCC sample resonant frequency, inductance and parasitic capacitance were measured (from room temperature to 500 °C with a high temperature measurement system comprising a muffle furnace and network analyzer. We found that the resonant frequency reduced and the inductance and parasitic capacitance increased slightly as the temperature increases. The relative permittivity can be calculated from experimental frequency, inductance and parasitic capacitance measurements. Calculating results show that the relative permittivity of DuPont 951 LTCC ceramic ceramic increases to 8.21 from room temperature to 500 °C.

  1. Soot, organics, and ultrafine ash from air- and oxy-fired coal combustion

    KAUST Repository

    Andersen, Myrrha E.

    2016-10-19

    Pulverized bituminous coal was burned in a 10. W externally heated entrained flow furnace under air-combustion and three oxy-combustion inlet oxygen conditions (28, 32, and 36%). Experiments were designed to produce flames with practically relevant stoichiometric ratios (SR. =1.2-1.4) and constant residence times (2.3. s). Size-classified fly ash samples were collected, and measurements focused on the soot, elemental carbon (EC), and organic carbon (OC) composition of the total and ultrafine (<0.6. μm) fly ash. Results indicate that although the total fly ash carbon, as measured by loss on ignition, was always acceptably low (<2%) with all three oxy-combustion conditions lower than air-combustion, the ultrafine fly ash for both air-fired and oxy-fired combustion conditions consists primarily of carbonaceous material (50-95%). Carbonaceous components on particles <0.6. μm measured by a thermal optical method showed that large fractions (52-93%) consisted of OC rather than EC, as expected. This observation was supported by thermogravimetric analysis indicating that for the air, 28% oxy, and 32% oxy conditions, 14-71% of this material may be OC volatilizing between 100. C and 550. C with the remaining 29-86% being EC/soot. However, for the 36% oxy condition, OC may comprise over 90% of the ultrafine carbon with a much smaller EC/soot contribution. These data were interpreted by considering the effects of oxy-combustion on flame attachment, ignition delay, and soot oxidation of a bituminous coal, and the effects of these processes on OC and EC emissions. Flame aerodynamics and inlet oxidant composition may influence emissions of organic hazardous air pollutants (HAPs) from a bituminous coal. During oxy-coal combustion, judicious control of inlet oxygen concentration and placement may be used to minimize organic HAP and soot emissions.

  2. Measuring transient high temperature thermal phenomena in hostile environment

    International Nuclear Information System (INIS)

    Brenden, B.B.; Hartman, J.S.; Reich, F.R.

    1980-01-01

    The design of equipment for measuring temperature and strain in a rapidly heated and pressurized cylinder of stainless steel is discussed. Simultaneous cinematography of the full circumference of the cylinder without interference with temperature and strain measurements is also illustrated. The integrated system uses a reflective chamber for the sample and requires careful consideration of the spectral energy distribution utilized by each instrument

  3. Diagnostic accuracy of routine postoperative body temperature measurements

    NARCIS (Netherlands)

    Vermeulen, Hester; Storm-Versloot, Marja N.; Goossens, Astrid; Speelman, Peter; Legemate, Dink A.

    2005-01-01

    BACKGROUND: On surgical wards, body temperature is routinely measured, but there is no proof that this is useful for detecting postoperative infection. The aim of this study was to compare temperature measurements (the test) with the confirmed absence or presence of a postoperative infection (the

  4. An array for measuring detailed soil temperature profiles

    Science.gov (United States)

    Soil temperature dynamics can provide insights into soil variables which are much more difficult or impossible to measure. We designed an array to measure temperature at precise depth increments. Data was collected to determine if the construction materials influence surface and near-surface tempera...

  5. Thermocouple design for measuring temperatures of small insects

    Science.gov (United States)

    A.A. Hanson; R.C. Venette

    2013-01-01

    Contact thermocouples often are used to measure surface body temperature changes of insects during cold exposure. However, small temperature changes of minute insects can be difficult to detect, particularly during the measurement of supercooling points. We developed two thermocouple designs, which use 0.51 mm diameter or 0.127 mm diameter copper-constantan wires, to...

  6. Three-wavelength pyrometer for measuring flame temperatures.

    Science.gov (United States)

    Cashdollar, K L

    1979-08-01

    This paper describes a pyrometer that measures the continuum radiation from particles in a flame or explosion at three wavelengths (0.8 microm, 0.9 microm, and 1.0 microm). The particle temperature is calculated from the radiation data using the Planck equation. Temperatures measured for coal dust explosions in a closed vessel are presented.

  7. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.

    2011-02-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well as the cell junction in thermal equilibrium with the chamber. The open-circuit voltage of PV module Voc is then measured using a short pulse of solar irradiation provided by a solar simulator. Repeating the measurements at different environment temperature (40-80°C) and solar irradiation S (200-1000W/m2), the correlation between the open-circuit voltage Voc, the junction temperature Tj, and solar irradiation S is derived.The fundamental correlation of the PV module is utilized for on-site monitoring of solar cell junction temperature using the measured Voc and S at a short time instant with open circuit. The junction temperature Tj is then determined using the measured S and Voc through the fundamental correlation. The outdoor test results show that the junction temperature measured using the present method, Tjo, is more accurate. The maximum error using the average surface temperature Tave as the junction temperature is 4.8 °C underestimation; while the maximum error using the present method is 1.3 °C underestimation. © 2010 Elsevier Ltd.

  8. Chemical composition and heterogeneous reactivity of soot generated in the combustion of diesel and GTL (Gas-to-Liquid) fuels and amorphous carbon Printex U with NO2 and CF3COOH gases

    Science.gov (United States)

    Tapia, A.; Salgado, S.; Martín, P.; Villanueva, F.; García-Contreras, R.; Cabañas, B.

    2018-03-01

    The heterogeneous reactions of nitrogen dioxide (NO2) and trifluoroacetic acid (CF3COOH) with soot produced by diesel and GTL (gas-to-liquid) fuels were investigated using a Knudsen flow reactor with mass spectrometry as a detection system for gas phase species. Soot was generated with a 4 cylinder diesel engine working under steady-state like urban operation mode. Heterogeneous reaction of the mentioned gases with a commercial carbon, Printex U, used as reference, was also analyzed. The initial and the steady-state uptake coefficients, γ0 and γss, respectively, were measured indicating that GTL soot reacts faster than diesel soot and Printex U carbon for NO2 gas reactant. According to the number of reacted molecules on the surface, Printex U soot presents more reducing sites than diesel and GTL soot. Initial uptake coefficients for GTL and diesel soot for the reaction with CF3COOH gas reactant are very similar and no clear conclusions can be obtained related to the initial reactivity. The number of reacted molecules calculated for CF3COOH reactions shows values two orders of magnitude higher than the corresponding to NO2 reactions, indicating a greater presence of basic functionalities in the soot surfaces. More information of the surface composition has been obtained using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) before and after the reaction of soot samples with gas reactants. As conclusion, the interface of diesel and GTL soot before reaction mainly consists of polycyclic aromatic hydrocarbons (PAHs), nitro-compounds as well as ether functionalities. After reaction with gas reactant, it was observed that PAHs and nitro-compounds remain on the soot surface and new spectral bands such as carbonyl groups (carboxylic acids, aldehydes, esters and ketones) are observed. Physical properties of soot from both fuels studied such as BET surface isotherm and SEM analysis were also developed and related to the observed reactivity.

  9. Multi-channel temperature measurement system for automotive battery stack

    Science.gov (United States)

    Lewczuk, Radoslaw; Wojtkowski, Wojciech

    2017-08-01

    A multi-channel temperature measurement system for monitoring of automotive battery stack is presented in the paper. The presented system is a complete battery temperature measuring system for hybrid / electric vehicles that incorporates multi-channel temperature measurements with digital temperature sensors communicating through 1-Wire buses, individual 1-Wire bus for each sensor for parallel computing (parallel measurements instead of sequential), FPGA device which collects data from sensors and translates it for CAN bus frames. CAN bus is incorporated for communication with car Battery Management System and uses additional CAN bus controller which communicates with FPGA device through SPI bus. The described system can parallel measure up to 12 temperatures but can be easily extended in the future in case of additional needs. The structure of the system as well as particular devices are described in the paper. Selected results of experimental investigations which show proper operation of the system are presented as well.

  10. Study on a transient optical fiber high temperature measurement system

    Science.gov (United States)

    Cai, Lulu; Liu, Yusha; Wang, Yutian

    2009-07-01

    High temperature is one of the most important parameters in the fields of scientific research and industrial production. At present, thermocouple, thermo resistive and radiance thermometer are already technologically mature which can be adopted to measure the general temperature, but when it comes to the transient high temperature that changes pretty quickly in wretched conditions, those traditional pyrometers can not meet the requirements any more. In this paper, we designed a transient optical high temperature measurement system. First, design of the temperature measurement probe. The system took blackbody cavity sensor together with optical fiber to receive the measured signal, here, the integrated emissivity model of the blackbody cavity was established and the optimum structure parameters were confirmed. Secondly, design of the entire temperature measurement system. A contact-noncontact measurement method was applied, which is to make the blackbody cavity and the measured high-temperature source contact, the fiber probe and the blackbody cavity noncontact, as a result, the error caused by contact measurement is overcame and the precision is guaranteed at the same time. In addition, a fiber grating was introduced as the wavelength filter device which can realize the dynamic filter of narrow-band signals and reduce the impact of background light. Thirdly, signal processing. In this part, we applied labVIEW software and wavelet analysis method. All of the signal acquisition and processing were realized in the labVIEW environment. Through calling matlab in labVIEW, the signals from optical fiber detector were wavelet denoised and decomposed, thus the temperature information was extracted, and the temperature value was obtained. On basis of wavelet transformation, the paper adopted the 4dB wavelet with horizontal scale of 5 to realize the feature extraction and noise removal, parts of the signals before and after the wavelet noise removal were given and analyzed

  11. Quantification of in situ temperature measurements on a PBI-based high temperature PEMFC unit cell

    DEFF Research Database (Denmark)

    Lebæk, Jesper; Ali, Syed Talat; Møller, Per

    2010-01-01

    The temperature is a very important operating parameter for all types of fuel cells. In the present work distributed in situ temperature measurements are presented on a polybenzimidazole based high temperature PEM fuel cell (HT-PEM). A total of 16 T-type thermocouples were embedded on both the an...

  12. Temperature lags of luminescence measurements in a commercial luminescence reader

    Energy Technology Data Exchange (ETDEWEB)

    Kitis, George [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece); Kiyak, Nafiye G. [ISIK University, Faculty of Science and Arts, Physics Department, Sile, 34980 Istanbul (Turkey); Polymeris, George S., E-mail: gspolymeris@ankara.edu.tr [Ankara University, Institute of Nuclear Sciences, Beşevler, 06100 Ankara (Turkey)

    2015-09-15

    The temperature recorded in thermoluminescence and optically stimulated luminescence equipments is not the temperature of the sample but that of the heating element on which the thermocouple is attached. Depending upon the rate of heating, a temperature difference appears between the samples and the heating element, termed as temperature lag, which could have serious effects on the curve shapes and trapping parameters. In the present work the temperature lag effect is studied in a newly developed luminescence equipment measuring both thermoluminescence and optically stimulated luminescence. It is found that the temperature lag could be large for heating rates above 2 K/s and it is strongly dependent upon the sample holder. A simple approximation method is proposed in order to both predict as well as correct for temperature lag effects in luminescence measurements.

  13. How is it possible to measure a nuclear temperature

    International Nuclear Information System (INIS)

    Tamain, B.

    1989-01-01

    Several methods for the measurement of nuclear temperatures are summarized. The concepts of hot nuclei and temperature are defined. The nuclear equation of state is presented. The statistical theory of hot nuclei decay properties is analyzed. The obtention of the excitation energy from the recoil velocity measurement is considered in the case of complete and incomplete fusion. The measurements of temperature and excitation energy from the properties of decay products are reviewed. The study shows that no measurement method is perfect. Moreover, it is necessary to select events for which the degree of dissipation of the incident energy is estimated

  14. Measuring temperatures with modified Kleiber 270B pyrometer

    International Nuclear Information System (INIS)

    Osch, E.V. van.

    1995-05-01

    At ECN a fast pyrometer is being used as a diagnostic tool for plasma disruption simulation experiments on candidate plasma facing materials for future thermonuclear fusion devices such as NET or ITER. The pyrometer is being used to measure the surface temperature response of the materials to short pulse high heat loads as induced by high power laser or electron beam, simulating the disrupting plasma's energy deposition. A procedure to measure surface temperatures without having to know surface emissivity in advance is described. The formulae needed in this procedure to obtain the correct temperature, starting from the initial incorrect temperature reading, are derived. Inversely, the formula to determine the emissivity of the surface when its temperature is known is equally derived. Finally, a small study on background level sensitivity is presented, showing the, in general, small effect of background on the temperature measurement. (orig.)

  15. Mutagenicity of diesel exhaust soot dispersed in phospholipid surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, W.; Keane, M.; Xing, S.; Harrison, J.; Gautam, M.; Ong, T.

    1994-06-01

    Organics extractable from respirable diesel exhaust soot particles by organic solvents have been known for some time to be direct acting frameshift mutagens in the Ames Salmonella typhimurium histidine reversion assay. Upon deposition in a pulmonary alveolus or respiratory bronchiole, respirable diesel soot particles will contact first the hypophase which is coated by and laden with surfactants. To model interactions of soot and pulmonary surfactant, the authors dispersed soots in vitro in the primary phospholipid pulmonary surfactant dipalmitoyl glycerophosphorylcholine (lecithin) (DPL) in physiological saline. They have shown that diesel soots dispersed in lecithin surfactant can express mutagenic activity, in the Ames assay system using S. typhimurium TA98, comparable to that expressed by equal amounts of soot extracted by dichloromethane/dimethylsulfoxide (DCM/DMSO). Here the authors report additional data on the same system using additional exhaust soots and also using two other phospholipids, dipalmitoyl glycerophosphoryl ethanolamine (DPPE), and dipalmitoyl phosphatidic acid (DPPA), with different ionic character hydrophilic moieties. A preliminary study of the surfactant dispersed soot in an eucaryotic cell test system also is reported.

  16. Measured gas and particle temperatures in VTT's entrained flow reactor

    DEFF Research Database (Denmark)

    Clausen, Sønnik; Sørensen, L.H.

    2006-01-01

    Particle and gas temperature measurements were carried out in experiments on VTTs entrained flow reactor with 5% and 10% oxygen using Fourier transform infrared emission spectroscopy (FTIR). Particle temperature measurements were performed on polish coal,bark, wood, straw particles, and bark...... and wood particles treated with additive. A two-color technique with subtraction of the background light was used to estimate particle temperatures during experiments. A transmission-emission technique was used tomeasure the gas temperature in the reactor tube. Gas temperature measurements were in good...... agreement with thermocouple readings. Gas lines and bands from CO, CO2 and H2O can be observed in the spectra. CO was only observed at the first measuring port (100ms) with the strongest CO-signal seen during experiments with straw particles. Variations in gas concentration (CO2 and H2O) and the signal from...

  17. An anatomically realistic temperature phantom for radiofrequency heating measurements

    Science.gov (United States)

    Graedel, Nadine N.; Polimeni, Jonathan R.; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L.

    2014-01-01

    Purpose An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the un-perfused case. We describe an anatomically realistic human head phantom that allows rapid 3D temperature mapping at 7 T. Methods The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature sensitive contrast agent (TmDOTMA−) validated by direct fiber optic temperature measurements. Results Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2–4 minutes. Conclusion Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. PMID:24549755

  18. Body Temperature Measurements for Metabolic Phenotyping in Mice

    Directory of Open Access Journals (Sweden)

    Carola W. Meyer

    2017-07-01

    Full Text Available Endothermic organisms rely on tightly balanced energy budgets to maintain a regulated body temperature and body mass. Metabolic phenotyping of mice, therefore, often includes the recording of body temperature. Thermometry in mice is conducted at various sites, using various devices and measurement practices, ranging from single-time probing to continuous temperature imaging. Whilst there is broad agreement that body temperature data is of value, procedural considerations of body temperature measurements in the context of metabolic phenotyping are missing. Here, we provide an overview of the various methods currently available for gathering body temperature data from mice. We explore the scope and limitations of thermometry in mice, with the hope of assisting researchers in the selection of appropriate approaches, and conditions, for comprehensive mouse phenotypic analyses.

  19. Thermoacoustic measurement of the temperature during microwave thermotherapy

    Science.gov (United States)

    Lou, Cunguang; Xing, Da; Nie, Liming

    2009-08-01

    Microwave thermotherapy (MT) has been an important treatment in oncology. The measurement of temperature during microwave thermotherapy is vital to ensure the safety of normal tissues. Thermoacoustic signals induced are temperature dependent. This phenomenon demonstrates that the thermal parameters are closely related to the generation of thermoacoustic pressure. Here we present the studies on pulsed microwave-induced thermoacoustic signals toward temperature monitoring of tissue thermotherapy. A high power pulsed microwave was used as thermoacoustic excitation source and heating source simultaneously, thermoacoustic pressure was captured by a multi-element linear transducer array. Excellent agreement was obtained between the inversion calculation results and the actual measurement temperature. The results suggest that thermoacoustic signals can be used to monitor thermotherapy temperature, and has the potential of reconstruct the temperature distribution by filter back-projection algorithm. This method has a great potential to develop into an integrated system for pulsed microwave thermotherapy and curative effect monitoring.

  20. Noncontact true temperature measurement. [of levitated sample using laser pyrometer

    Science.gov (United States)

    Lee, Mark C.; Allen, James L.

    1987-01-01

    A laser pyrometer has been developed for acquiring the true temperature of a levitated sample. The laser beam is first expanded to cover the entire cross-sectional surface of the target. For calibration of such a system, the reflectivity signal of an ideal 0.95 cm diameter gold-coated sphere (reflectivity = 0.99) is used as the reference for any other real targets. The emissivity of the real target can then be calculated. The overall system constant is obtained by passively measuring the radiance of a blackbody furnace (emissivity = 1.0) at a known, arbitrary temperature. Since the photo sensor used is highly linear over the entire operating temperature range, the true temperature of the target can then be computed. Preliminary results indicate that true temperatures thus obtained are in excellent correlation with thermocouple measured temperatures.

  1. Body Temperature Measurements for Metabolic Phenotyping in Mice

    Science.gov (United States)

    Meyer, Carola W.; Ootsuka, Youichirou; Romanovsky, Andrej A.

    2017-01-01

    Endothermic organisms rely on tightly balanced energy budgets to maintain a regulated body temperature and body mass. Metabolic phenotyping of mice, therefore, often includes the recording of body temperature. Thermometry in mice is conducted at various sites, using various devices and measurement practices, ranging from single-time probing to continuous temperature imaging. Whilst there is broad agreement that body temperature data is of value, procedural considerations of body temperature measurements in the context of metabolic phenotyping are missing. Here, we provide an overview of the various methods currently available for gathering body temperature data from mice. We explore the scope and limitations of thermometry in mice, with the hope of assisting researchers in the selection of appropriate approaches, and conditions, for comprehensive mouse phenotypic analyses. PMID:28824441

  2. Influence of soot mixing state on aerosol light absorption and single scattering albedo during air mass aging at a polluted regional site in northeastern China

    Science.gov (United States)

    Cheng, Y. F.; Berghof, M.; Garland, R. M.; Wiedensohler, A.; Wehner, B.; Müller, T.; Su, H.; Zhang, Y. H.; Achtert, P.; Nowak, A.; PöSchl, U.; Zhu, T.; Hu, M.; Zeng, L. M.

    2009-01-01

    An aerosol optical closure study was performed using the observed high time- and size-resolved soot mixing states determined by a Volatility Tandem Differential Mobility Analyzer (VTDMA) at a polluted regional site, Yufa, in the south of Beijing during the summer of 2006. Good agreement was found between the simulated and measured aerosol absorption (σap, R = 0.9) and scattering (σsp, R ≥ 0.95). The soot mixing state at Yufa can be generally determined by VTDMA, in terms of properly predicting the σap using a simple optical model combined with spherical homogeneous and core-shell coated Mie codes. The possible uncertainties in the modeled σap were discussed. Rapid soot aging was observed, which led to large variations in the fractional contributions to σap by externally mixed and coated soot. On average, about 37% of the σap (˜10-60%) arose by the coated soot. The coating enhancement in σap and σsp of the coated soot can reach up to a factor of 8-10 within several hours owing to the secondary processing during daytime. It was contributed not only by the increased thickness of coating shell, but also the transition of soot from externally mixed to coated one. Hence, assuming constant soot mixing state for the regional climate model is not realistic and may lead to uncertainties. In the highly polluted region in northeastern China, the aerosol single scattering albedo may increase very fast owing to the rapid secondary particle formation and condensation (up to 0.90-0.95). This increase took place although the concurrent coating processing enhanced the light absorption capability of soot.

  3. The realization of temperature controller for small resistance measurement system

    Science.gov (United States)

    Sobecki, Jakub; Walendziuk, Wojciech; Idzkowski, Adam

    2017-08-01

    This paper concerns the issues of construction and experimental tests of a temperature stabilization system for small resistance increments measurement circuits. After switching the system on, a PCB board heats up and the long-term temperature drift altered the measurement result. The aim of this work is reducing the time of achieving constant nominal temperature by the measurement system, which would enable decreasing the time of measurements in the steady state. Moreover, the influence of temperatures higher than the nominal on the measurement results and the obtained heating curve were tested. During the working process, the circuit heats up to about 32 °C spontaneously, and it has the time to reach steady state of about 1200 s. Implementing a USART terminal on the PC and an NI USB-6341 data acquisition card makes recording the data (concerning temperature and resistance) in the digital form and its further processing easier. It also enables changing the quantity of the regulator settings. This paper presents sample results of measurements for several temperature values and the characteristics of the temperature and resistance changes in time as well as their comparison with the output values. The object identification is accomplished due to the Ziegler-Nichols method. The algorithm of determining the step characteristics parameters and examples of computations of the regulator settings are included together with example characteristics of the object regulation.

  4. The extent of temporal smearing in surface-temperature histories derived from borehole temperature measurements

    Science.gov (United States)

    Clow, G.D.

    1992-01-01

    The ability of borehole temperature data to resolve past climatic events is investigated using Backus-Gilbert inversion methods. Two experimental approaches are considered: (1) the data consist of a single borehole temperature profile, and (2) the data consist of climatically-induced temperature transients measured within a borehole during a monitoring experiment. The sensitivity of the data's resolving power to the vertical distribution of the measurements, temperature measurement errors, the inclusion of a local meteorological record, and the duration of a monitoring experiment, are investigated. The results can be used to help interpret existing surface temperature histories derived from borehole temperature data and to optimize future experiments for the detection of climatic signals. ?? 1992.

  5. Surface temperature measurements of heterogeneous explosives by IR emission

    Energy Technology Data Exchange (ETDEWEB)

    Henson, B.F.; Funk, D.J.; Dickson, P.M.; Fugard, C.S.; Asay, B.W.

    1998-03-01

    The authors present measurements of the integrated IR emission (1--5 {micro}m) from both the heterogeneous explosive PBX 9501 and pure HMX at calibrated temperatures from 300 C to 2,500 C. The IR power emitted as a function of temperature is that expected of a black body, attenuated by a unique temperature independent constant which the authors report as the thermal emissivity. The authors have utilized this calibration of IR emission in measurements of the surface temperature from PBX 9501 subject to 1 GPa, two dimensional impact, and spontaneous ignition in unconfined cookoff. They demonstrate that the measurement of IR emission in this spectral region provides a temperature probe of sufficient sensitivity to resolve the thermal response from the solid explosive throughout the range of weak mechanical perturbation, prolonged heating to ignition, and combustion.

  6. Scanning optical pyrometer for measuring temperatures in hollow cathodes.

    Science.gov (United States)

    Polk, J E; Marrese-Reading, C M; Thornber, B; Dang, L; Johnson, L K; Katz, I

    2007-09-01

    Life-limiting processes in hollow cathodes are determined largely by the temperature of the electron emitter. To support cathode life assessment, a noncontact temperature measurement technique which employs a stepper motor-driven fiber optic probe was developed. The probe is driven inside the hollow cathode and collects light radiated by the hot interior surface of the emitter. Ratio pyrometry is used to determine the axial temperature profile. Thermocouples on the orifice plate provide measurements of the external temperature during cathode operation and are used to calibrate the pyrometer system in situ with a small oven enclosing the externally heated cathode. The diagnostic method and initial measurements of the temperature distribution in a hollow cathode are discussed.

  7. The electronic temperature control and measurements reactor fuel rig circuits

    International Nuclear Information System (INIS)

    Glowacki, S.W.

    1980-01-01

    The electronic circuits of two digital temperature meters developed for the thermocouple of Ni-NiCr type are described. The output thermocouple signal as converted by means of voltage-to-freguency converter. The frequency is measured by a digital scaler controled by quartz generator signals. One of the described meter is coupled with digital temperature controler which drives the power stage of the reactor rig heater. The internal rig temperature is measured by the thermocouple providing the input signal to the mentioned voltage-to-frequency converter, that means the circuits work in the negative feedback loop. The converter frequency-to-voltage ratio is automatically adjusted to match to thermocouple sensitivity changes in the course of the temperature variations. The accuracy of measuring system is of order of +- 1degC for thermocouple temperature changes from 523 K up to 973 K (50degC up to 700degC). (author)

  8. Acoustic temperature profile measurement technique for large combustion chambers

    Science.gov (United States)

    Venkateshan, S. P.; Shakkottai, P.; Kwack, E. Y.; Back, L. H.

    1989-01-01

    Measurement of times of flight of sound waves can be used to determine temperatures in a gas. This paper describes a system, based on this principle, that is capable of giving the temperature profile in a nonisothermal gas volume, for example, prevalent in a large furnace. The apparatus is simple, rugged, accurate, and capable of being automated for process control applications. It is basically an acoustic waveguide where the outside temperature profile is transferred to a chosen gas contained inside the guide.

  9. Technology and education: First approach for measuring temperature with Arduino

    Science.gov (United States)

    Carrillo, Alejandro

    2017-04-01

    This poster session presents some ideas and approaches to understand concepts of thermal equilibrium, temperature and heat in order to bulid a man-nature relationship in a harmonious and responsible manner, emphasizing the interaction between science and technology, without neglecting the relationship of the environment and society, an approach to sustainability. It is proposed the development of practices that involve the use of modern technology, of easy access and low cost to measure temperature. We believe that the Arduino microcontroller and some temperature sensors can open the doors of innovation to carry out such practices. In this work we present some results of simple practices presented to a population of students between the ages of 16 and 17 years old. The practices in this proposal are: Zero law of thermodynamics and the concept of temperature, calibration of thermometers and measurement of temperature for heating and cooling of three different substances under the same physical conditions. Finally the student is asked to make an application that involves measuring of temperature and other physical parameters. Some suggestions are: to determine the temperature at which we take some food, measure the temperature difference at different rooms of a house, housing constructions that favour optimal condition, measure the temperature of different regions, measure of temperature trough different colour filters, solar activity and UV, propose applications to understand current problems such as global warming, etc. It is concluded that the Arduino practices and electrical sensors increase the cultural horizon of the students while awaking their interest to understand their operation, basic physics and its application from a modern perspective.

  10. Magnetometry and electrical transport measurements of high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Mun Keat [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-13

    Prior to preparing and performing measurements in pulsed magnetic fields, it is necessary to characterize them. For the cuprates such as HgBa2CuO4+δ (Hg1201), measurements of the superconducting temperature is essential. This experiment comprises just such a characterization of Hg1201 crystals to be used for pulsed magnetic field measurements.

  11. Spectroscopic analysis applied to temperature measurement in plasmas

    International Nuclear Information System (INIS)

    Fieffe-Prevost, P.

    1978-01-01

    The plasma temperature is defined only if the plasma is in a state near thermodynamic equilibrium. This plasma state is analysed in detail and spectroscopic methods for measuring the temperature are discussed. As an application the hydrogen arc of the National Institute of Metrology of the Conservatoire National des Arts et Metiers (Paris) is briefly described [fr

  12. Two particle correlation studies and measurement of temperature

    International Nuclear Information System (INIS)

    Rana, T.K.; Bhattacharya, C.; Kundu, S.; Banerjee, K.; Dey, A.; Ghosh, T.K.; Mukherjee, G.; Gupta, D.; Meena, J.K.; Roy, A.; Dhara, P.; Banerjee, S.R.; Bhattacharya, S.

    2007-01-01

    In order to obtain more detailed information about the emission temperatures, we have measured two particle correlation function at small relative momenta for the reaction 20 Ne+ 12 C at 145 MeV. Here, we report the temperature extracted from the correlation studies and compared it with those obtained from slope thermometer

  13. Survey of Temperature Measurement Techniques For Studying Underwater Shock Waves

    Science.gov (United States)

    Danehy, Paul M.; Alderfer, David W.

    2004-01-01

    Several optical methods for measuring temperature near underwater shock waves are reviewed and compared. The relative merits of the different techniques are compared, considering accuracy, precision, ease of use, applicable temperature range, maturity, spatial resolution, and whether or not special additives are required.

  14. Miniature ingestible telemeter devices to measure deep-body temperature

    Science.gov (United States)

    Pope, J. M.; Fryer, T. B. (Inventor)

    1976-01-01

    A telemetry device comprised of a pill-size ingestible transmitter developed to obtain deep body temperature measurements of a human is described. The device has particular utility in the medical field where deep body temperatures provide an indication of general health.

  15. Time-Resolved Surface Temperature Measurement for Pulsed Ablative Thrusters

    National Research Council Canada - National Science Library

    Antonsen, Erik

    2003-01-01

    .... The diagnostic draws on heritage from the experimental dynamic crack propagation community which has used photovoltaic infrared detectors to measure temperature rise in materials in the process of fracture...

  16. On bias of kinetic temperature measurements in complex plasmas

    DEFF Research Database (Denmark)

    Kantor, M.; Moseev, D.; Salewski, Mirko

    2014-01-01

    The kinetic temperature in complex plasmas is often measured using particle tracking velocimetry. Here, we introduce a criterion which minimizes the probability of faulty tracking of particles with normally distributed random displacements in consecutive frames. Faulty particle tracking results i...

  17. Lower atmospheric temperature profile measurements using a Raman lidar

    Science.gov (United States)

    Melfi, S. H.; Whiteman, D.

    1986-01-01

    A Raman lidar system was used to measure the temperature profile of the upper troposphere and lower stratosphere. The system consists of a tripled Nd-YAG laser and a 1.5 meter diameter telescope. Two photomultipliers are used at the output of the telescope to allow for measurements at both the laser wavelength and at the Raman shifted wavelength due to atmospheric nitrogen. The signal from the photomultipliers is recorded as photon counts in 1 microsec bins. The results of a number of laser shots are summed together to provide atmospheric returns which have acceptable signal to noise characteristics. Measurements of the Raman nitrogen return were acquired up to an altitude in excess of 20 km. Temperature profiles were retrieved from the attenuation corrected Raman nitrogen return assuming the atmosphere to be in hydrostatic equilibrium and using the ideal gas law. Retrieved temperature profiles are shown compared with independent temperature measurements.

  18. Automated measurement of cattle surface temperature and its correlation with rectal temperature.

    Directory of Open Access Journals (Sweden)

    HongXiang Kou

    Full Text Available The body temperature of cattle varies regularly with both the reproductive cycle and disease status. Establishing an automatic method for monitoring body temperature may facilitate better management of reproduction and disease control in cattle. Here, we developed an Automatic Measurement System for Cattle's Surface Temperature (AMSCST to measure the temperature of metatarsus by attaching a special shell designed to fit the anatomy of cattle's hind leg. Using AMSCST, the surface temperature (ST on the metatarsus of the hind leg was successively measured during 24 hours a day with an interval of one hour in three tested seasons. Based on ST and rectal temperature (RT detected by AMSCST and mercury thermometer, respectively, a linear mixed model was established, regarding both the time point and seasonal factors as the fixed effects. Unary linear correlation and Bland-Altman analysis results indicated that the temperatures measured by AMSCST were closely correlated to those measured by mercury thermometer (R2 = 0.998, suggesting that the AMSCST is an accurate and reliable way to detect cattle's body temperature. Statistical analysis showed that the differences of STs among the three seasons, or among the different time points were significant (P<0.05, and the differences of RTs among the different time points were similarly significant (P<0.05. The prediction accuracy of the mixed model was verified by 10-fold cross validation. The average difference between measured RT and predicted RT was about 0.10 ± 0.10°C with the association coefficient of 0.644, indicating the feasibility of this model in measuring cattle body temperature. Therefore, an automated technology for accurately measuring cattle body temperature was accomplished by inventing an optimal device and establishing the AMSCST system.

  19. Combined NMR moisture, temperature and pressure measurements during heating

    Directory of Open Access Journals (Sweden)

    Pel L.

    2013-09-01

    Full Text Available For model validation, quantitative measurements of the evolution of moisture, temperature, and pressure distributions in time are needed. For this purpose, we have developed an NMR setup to measure the moisture transport in heated building materials. The measured combined moisture content and temperature profiles give a unique insight in the moisture transport and dehydration kinetics inside concrete during fire. These measurements give the first quantitative proof for the build-up of a moisture peak due to the vapor pressure build-up. In this study we have also combined for the first time the measurement of the moisture and temperature profiles with the measurement of the pressure at one position, which show that the pressure build up is directly related to the moisture profiles.

  20. Investigation of soot and carbon formation in small gas turbine combustors

    Science.gov (United States)

    Rosfjord, T. J.

    1982-01-01

    An investigation of hardware configurations which attempt to minimize carbon and soot-production without sacrificing performance in small gas turbine combustors was conducted. Four fuel injectors, employing either airblast atomization, pressure atomization, or fuel vaporization techniques were combined with nozzle air swirlers and injector sheaths. Eight configurations were screened at sea-level takeoff and idle test conditions. Selected configurations were focused upon in an attempt to quantify the influence of combustor pressure, inlet temperature, primary zone operation, and combustor loading on soot and carbon formation. Cycle tests were also performed. It was found that smoke emission levels depended on the combustor fluid mechanics, the atomization quality of the injector and the fuel hydrogen content.

  1. Wet method for measuring starch gelatinization temperature using electrical conductivity.

    Science.gov (United States)

    Morales-Sanchez, E; Figueroa, J D C; Gaytan-Martínez, M

    2009-09-01

    The objective of the present study was to develop a method for obtaining the gelatinization temperature of starches by using electrical conductivity. Native starches from corn, rice, potato, and wheat were prepared with different proportions of water and heated from room temperature to 90 degrees C, in a device especially designed for monitoring the electrical conductivity as a function of temperature. The results showed a linear trend of the electrical conductivity with the temperature until it reaches the onset gelatinization temperature. After that point, the electrical conductivity presented an increment or decrement depending on the water content in the sample and it was related to starch swelling and gelatinization phenomena. At the end gelatinization temperature, the conductivity becomes stable and linear, indicating that there are no more changes of phase. The starch gelatinization parameter, which was evaluated in the 4 types of starches using the electrical conductivity, was compared with those obtained by using differential scanning calorimeter (DSC). The onset temperature at which the electrical conductivity increased or decreased was found to be similar to that obtained by DSC. Also, the final temperature at which the electrical conductivity returned to linearity matched the end gelatinization temperature of the DSC. Further, a wet method for measuring the onset, peak, and end gelatinization temperatures as a function of temperature using the electrical conductivity curves is presented for a starch-water suspension.

  2. Immobilization of soot particles in a silica matrix: A sorbent-carrier system for studying organic chemical sorption.

    Science.gov (United States)

    Nguyen, Thanh H; Sabbah, Isam; Ball, William P

    2005-09-01

    A new method for studying sorption with diesel and hexane sootwas developed, tested, and applied. A commercial silica-based chromatography medium was used as an inert inorganic carrier for immobilization (entrapment) of soot particles and their aggregates, thus creating a combined sorbent for sorption of hydrophobic organic chemicals (HOCs). After precombustion to remove potential organic carbon contaminants, the silica particles and soot samples were mixed under dry conditions that allowed the soot to be incorporated within the pore structure of the much larger (> 180 microm) carrier particles. Unincorporated soot was removed by multiple rinses with Milli-Q water. Sorption rate and equilibrium experiments were conducted, using phenanthrene as a probe HOC. Strong nonlinear sorption of phenanthrene was observed, in agreement with results previously obtained using air-bridge and flocculation-based methods. Batch kinetic studies suggested that 60 d of prewetting is required to obtain full water saturation, as perhaps needed for proper assessment of phenanthrene uptake rate by soot in aqueous systems. Forthe determination of equilibrium phenanthrene sorption, however, 1-d prewetting is sufficient so long as final equilibration is for at least 60 d. The new method is a practical approach to sorption measurement that may prove especially useful for study of strongly sorbing chemicals.

  3. Temperature and voltage measurement in quantum systems far from equilibrium

    Science.gov (United States)

    Shastry, Abhay; Stafford, Charles A.

    2016-10-01

    We show that a local measurement of temperature and voltage for a quantum system in steady state, arbitrarily far from equilibrium, with arbitrary interactions within the system, is unique when it exists. This is interpreted as a consequence of the second law of thermodynamics. We further derive a necessary and sufficient condition for the existence of a solution. In this regard, we find that a positive temperature solution exists whenever there is no net population inversion. However, when there is a net population inversion, we may characterize the system with a unique negative temperature. Voltage and temperature measurements are treated on an equal footing: They are simultaneously measured in a noninvasive manner, via a weakly coupled thermoelectric probe, defined by requiring vanishing charge and heat dissipation into the probe. Our results strongly suggest that a local temperature measurement without a simultaneous local voltage measurement, or vice versa, is a misleading characterization of the state of a nonequilibrium quantum electron system. These results provide a firm mathematical foundation for voltage and temperature measurements far from equilibrium.

  4. MPPT Technique Based on Current and Temperature Measurements

    Directory of Open Access Journals (Sweden)

    Eduardo Moreira Vicente

    2015-01-01

    Full Text Available This paper presents a new maximum power point tracking (MPPT method based on the measurement of temperature and short-circuit current, in a simple and efficient approach. These measurements, which can precisely define the maximum power point (MPP, have not been used together in other existing techniques. The temperature is measured with a low cost sensor and the solar irradiance is estimated through the relationship of the measured short-circuit current and its reference. Fast tracking speed and stable steady-state operation are advantages of this technique, which presents higher performance when compared to other well-known techniques.

  5. Continuous temperature measurements on the pouring stand for casting moulds

    Directory of Open Access Journals (Sweden)

    W. Leśniewski

    2008-04-01

    Full Text Available The results of temperature measurements of liquid iron alloys obtained by means of the pyrometer, PDR-1800 series, are presented in the paper. The measurements were performed in conditions determined by the kind of a pouring device. The results obtained for bottom-tap ladles were supplemented by laboratory measurements. These results allow explaining significant differences in the results of temperature measurements performed in pouring ladles by means of the pyrometric method and immersible thermocouple, which - in turn - improves assessment of metal thermal parameters in pouring devices.

  6. Ring to measure magnetic permeability at cryogenic temperatures

    CERN Multimedia

    1977-01-01

    While for magn. permeability measurements at room temperature a split-coil permeameter is used (see photo 7708553X), for measurements at cryogenic temperatures the excitation and the flux-measuring coils are wound directly on the ring sample by means of a toroidal winding machine. The ring in the picture was made to select the mild steel for the ISR Prototype Superconducting Quadrupole(see photo 7702690X). The excitation coil was wound with 1 mm diam. copper wire and had about 2730 turns. For measurements at 4.2 K a max. current of 90 A was used. See also photos 7708553X,7708100,7708103.

  7. Kinetic study of diesel soot oxidation: application to simulation of diesel particulate filter regeneration; Etude cinetique de la combustion des suies diesel: application a la modelisation de la regeneration du filtre a particule

    Energy Technology Data Exchange (ETDEWEB)

    Huguet, Ch.

    2005-11-15

    Because of their toxicity, soot are considered as the most important pollutant from Diesel engines. The Diesel Particulate Filter (DPF) is widely deployed in Europe to address the significant reductions in particulate emissions required by increasingly stringent emission standards, both for heavy duty vehicles and passenger cars. Such a DPF filtrates above 99% of soot emissions and must be regularly regenerated. The use of additive allows to decrease the soot oxidation temperature to values which can be reached by appropriate engine tuning. The soot addition is a dominant parameter for the development of regeneration strategies. Its influence must be correctly represented by models. This Ph-D was performed at IFP in collaboration with ADEME and was supported by the LCSR at Orleans. The aim of the present research is to develop a kinetic mechanism characteristic of Diesel soot oxidation, which can be integrated into a DPF regeneration model and used for engine control. The oxidation study was based on soot characterisation and reaction kinetics investigations. The samples of Diesel soot were collected, without and with Cerium/Iron additive, by using two engines points representative of two normalized European cycles (ECE and EUDC). Thermal and composition analyses with techniques such as XPS, XRD or TEM were used to determine their physical and chemical properties. Their oxidation kinetics was experimentally studied on a synthetic gas bench (SGB) with a fixed bed reactor. Different tests were performed: temperature-programmed oxidation (TPO), Isothermal oxidation (IO), and sequential oxidation. The results allowed to correlate Diesel soot physical and chemical properties with their oxidation rate. A kinetic model was developed, which is based on global carbon consummation law and distinguishes the oxidation of different soot components. The simulation results agree very well with the experimental results of Diesel soot oxidation. (author)

  8. FFTF fuel assembly outlet temperature measurements and comparison to predictions

    International Nuclear Information System (INIS)

    Cramer, E.R.

    1984-06-01

    The data from the FFTF core outlet thermocouples have been valuable in verifying the performance of the core assemblies. The data have been useful to the experimental program and as an aid in understanding some reactor operating phenomena. The thermocouple reliability and repeatability have been good. Almost all of the fueled positions in the core have 3 operable thermocouples and every position has at least one. Differences between the measured assembly outlet temperatures and the calculated outlet temperatures have generally been small. Where significant differences have occurred, an explanation has been found. The difference between the measured and calculated outlet temperatures for each assembly remains constant during the cycle

  9. Evaluation of Raytek infrared pyrometer for continuous propellant temperature measurement

    Science.gov (United States)

    Dykstra, Mark D.

    1990-01-01

    The primary purpose of this evaluation was to determine if the Raytek IR pyrometer that was installed in the 600 gallon propellant mixers could be used to provide a continuous, accurate, reliable measurement of the propellant temperature during mixing. The Raytek infrared sensor is not recommended to be used for controlling propellant temperature nor for inspection buy-off. The first part of the evaluation was to determine the accuracy of the sensor in measuring the propellant temperature. The second part was to determine the reliability of the air purge design in preventing contamination of the IR window.

  10. Measurement of Temperature Dependent Apparent Specific Heat Capacity in Electrosurgery.

    Science.gov (United States)

    Karaki, Wafaa; Akyildiz, Ali; Borca Tasciuc, Diana-Andra; De, Suvranu

    2016-01-01

    This paper reports on the measurement of temperature dependent apparent specific heat of ex-vivo porcine liver tissue during radiofrequency alternating current heating for a large temperature range. The difference between spatial and temporal evolution of experimental temperature, obtained during electrosurgical heating by infrared thermometry, and predictions based on finite element modeling was minimized to obtain the apparent specific heat. The model was based on transient heat transfer with internal heat generation considering heat storage along with conduction. Such measurements are important to develop computational models for real time simulation of electrosurgical procedures.

  11. Influence of temperature to quenching on liquid scintillation measurement

    CERN Document Server

    Kato, T

    2003-01-01

    The amount of quench is measured with liquid scintillation spectrometer changing the temperature of the sample. The range of the changed temperature is between 0 deg C and 35 deg C. The measurement is carried out for three kinds of unquenched standard, two quenched standards and fifteen kinds of scintillation cocktail and the mixed sample. It is confirmed that the amount of quench increases for all samples as the temperature rises. The influence of the changed amount of quench to the quench correction is examined. (author)

  12. Dielectric properties measurement system at cryogenic temperatures and microwave frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Molla, J.; Ibarra, A.; Margineda, J.; Zamarro, J. M.; Hernandez, A.

    1994-07-01

    A system based on the resonant cavity method has been developed to measure the permittivity and loss tangent at 12-18 GHz over the temperature range 80 K to 300 K. Changes of permittivity as low as 0.01 % in the range 1 to 30, and 3 x 10{sup 6} for loss tangent values below 10{sup 2}, can be obtained without requiring temperature stability. The thermal expansion coefficient and resistivity factor of copper have been measured between 80 K and 300 K. Permittivity of sapphire and loss tangent of alumina of 99.9 % purity in the same temperature range are presented. (Author) 23 refs.

  13. Modeling the wet bulb globe temperature using standard meteorological measurements.

    Science.gov (United States)

    Liljegren, James C; Carhart, Richard A; Lawday, Philip; Tschopp, Stephen; Sharp, Robert

    2008-10-01

    The U.S. Army has a need for continuous, accurate estimates of the wet bulb globe temperature to protect soldiers and civilian workers from heat-related injuries, including those involved in the storage and destruction of aging chemical munitions at depots across the United States. At these depots, workers must don protective clothing that increases their risk of heat-related injury. Because of the difficulty in making continuous, accurate measurements of wet bulb globe temperature outdoors, the authors have developed a model of the wet bulb globe temperature that relies only on standard meteorological data available at each storage depot for input. The model is composed of separate submodels of the natural wet bulb and globe temperatures that are based on fundamental principles of heat and mass transfer, has no site-dependent parameters, and achieves an accuracy of better than 1 degree C based on comparisons with wet bulb globe temperature measurements at all depots.

  14. Measuring gas temperature during spin-exchange optical pumping process

    Science.gov (United States)

    Normand, E.; Jiang, C. Y.; Brown, D. R.; Robertson, L.; Crow, L.; Tong, X.

    2016-04-01

    The gas temperature inside a Spin-Exchange Optical Pumping (SEOP) laser-pumping polarized 3He cell has long been a mystery. Different experimental methods were employed to measure this temperature but all were based on either modelling or indirect measurement. To date there has not been any direct experimental measurement of this quantity. Here we present the first direct measurement using neutron transmission to accurately determine the number density of 3He, the temperature is obtained using the ideal gas law. Our result showed a surprisingly high gas temperature of 380°C, compared to the 245°C of the 3He cell wall temperature and 178°C of the optical pumping oven temperature. This experiment result may be used to further investigate the unsolved puzzle of the "X-factor" in the SEOP process which places an upper bound to the 3He polarization that can be achieved. Additional spin relaxation mechanisms might exist due to the high gas temperature, which could explain the origin of the X-factor.

  15. Low-temperature mobility measurements on CMOS devices

    International Nuclear Information System (INIS)

    Hairpetian, A.; Gitlin, D.; Viswanathan, C.R.

    1989-01-01

    The surface channel mobility of carriers in eta- and rho-MOS transistors fabricated in a CMOS process was accurately determined at low temperatures down to 5 Κ. The mobility was obtained by an accurate measurement of the inversion charge density using a split C-V technique and the conductance at low drain voltages. The split C-V technique was validated at all temperatures using a one-dimensional Poisson solver (MOSCAP), which was modified for low-temperature application. The mobility dependence on the perpendicular electric field for different substrate bias values appears to have different temperature dependence for eta- and rho-channel devices. The electron mobility increases with a decrease in temperature at all gate voltages. On the other hand, the hole mobility exhibits a different temperature behavior depending upon whether the gate voltage corresponds to strong inversion or is near threshold

  16. Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

    International Nuclear Information System (INIS)

    Liu Qiuyan; Li Hong; Chen Zhipeng; Xie Jinlin; Liu Wandong

    2011-01-01

    Continuous emission spectrum measurement is applied for the inconvenient diagnostics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron temperature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method. (low temperature plasma)

  17. Modern gas-based temperature and pressure measurements

    CERN Document Server

    Pavese, Franco

    2013-01-01

    This 2nd edition volume of Modern Gas-Based Temperature and Pressure Measurements follows the first publication in 1992. It collects a much larger set of information, reference data, and bibliography in temperature and pressure metrology of gaseous substances, including the physical-chemical issues related to gaseous substances. The book provides solutions to practical applications where gases are used in different thermodynamic conditions. Modern Gas-Based Temperature and Pressure Measurements, 2nd edition is the only comprehensive survey of methods for pressure measurement in gaseous media used in the medium-to-low pressure range closely connected with thermometry. It assembles current information on thermometry and manometry that involve the use of gaseous substances which are likely to be valid methods for the future. As such, it is an important resource for the researcher. This edition is updated through the very latest scientific and technical developments of gas-based temperature and pressure measurem...

  18. Soil temperature variability in complex terrain measured using fiber-optic distributed temperature sensing

    Science.gov (United States)

    Soil temperature (Ts) exerts critical controls on hydrologic and biogeochemical processes but magnitude and nature of Ts variability in a landscape setting are rarely documented. Fiber optic distributed temperature sensing systems (FO-DTS) potentially measure Ts at high density over a large extent. ...

  19. A nonintrusive temperature measuring system for estimating deep body temperature in bed.

    Science.gov (United States)

    Sim, S Y; Lee, W K; Baek, H J; Park, K S

    2012-01-01

    Deep body temperature is an important indicator that reflects human being's overall physiological states. Existing deep body temperature monitoring systems are too invasive to apply to awake patients for a long time. Therefore, we proposed a nonintrusive deep body temperature measuring system. To estimate deep body temperature nonintrusively, a dual-heat-flux probe and double-sensor probes were embedded in a neck pillow. When a patient uses the neck pillow to rest, the deep body temperature can be assessed using one of the thermometer probes embedded in the neck pillow. We could estimate deep body temperature in 3 different sleep positions. Also, to reduce the initial response time of dual-heat-flux thermometer which measures body temperature in supine position, we employed the curve-fitting method to one subject. And thereby, we could obtain the deep body temperature in a minute. This result shows the possibility that the system can be used as practical temperature monitoring system with appropriate curve-fitting model. In the next study, we would try to establish a general fitting model that can be applied to all of the subjects. In addition, we are planning to extract meaningful health information such as sleep structure analysis from deep body temperature data which are acquired from this system.

  20. Towards predictive simulations of soot formation: from surrogate to turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Blanquart, Guillaume [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2017-03-28

    The combustion of transportation fuels leads to the formation of several kinds of pollutants, among which are soot particles. These particles, also formed during coal combustion and in fires, are the source of several health problems and environmental issues. Unfortunately, our current understanding of the chemical and physical phenomena leading to the formation of soot particles remains incomplete, and as a result, the predictive capability of our numerical tools is lacking. The objective of the work was to reduce the gap in the present understanding and modeling of soot formation both in laminar and turbulent flames. The effort spanned several length scales from the molecular level to large scale turbulent transport.

  1. X3 expansion tube driver gas spectroscopy and temperature measurements

    Science.gov (United States)

    Parekh, V.; Gildfind, D.; Lewis, S.; James, C.

    2017-11-01

    The University of Queensland's X3 facility is a large, free-piston driven expansion tube used for super-orbital and high Mach number scramjet aerothermodynamic studies. During recent development of new scramjet test flow conditions, experimentally measured shock speeds were found to be significantly lower than that predicted by initial driver performance calculations. These calculations were based on ideal, isentropic compression of the driver gas and indicated that loss mechanisms, not accounted for in the preliminary analysis, were significant. The critical determinant of shock speed is peak driver gas sound speed, which for a given gas composition depends on the peak driver gas temperature. This temperature may be inaccurately estimated if an incorrect fill temperature is assumed, or if heat losses during driver gas compression are significant but not accounted for. For this study, the ideal predicted peak temperature was 3750 K, without accounting for losses. However, a much lower driver temperature of 2400 K is suggested based on measured experimental shock speeds. This study aimed to measure initial and peak driver gas temperatures for a representative X3 operating condition. Examination of the transient temperatures of the driver gas and compression tube steel wall during the initial fill process showed that once the filling process was complete, the steady-state driver gas temperature closely matched the tube wall temperature. Therefore, while assuming the gas is initially at the ambient laboratory temperature is not a significant source of error, it can be entirely mitigated by simply monitoring tube wall temperature. Optical emission spectroscopy was used to determine the driver gas spectra after diaphragm rupture; the driver gas emission spectrum exhibited a significant continuum radiation component, with prominent spectral lines attributed to contamination of the gas. A graybody approximation of the continuum suggested a peak driver gas temperature of

  2. Self-calibrated active pyrometer for furnace temperature measurements

    Science.gov (United States)

    Woskov, Paul P.; Cohn, Daniel R.; Titus, Charles H.; Surma, Jeffrey E.

    1998-01-01

    Pyrometer with a probe beam superimposed on its field-of-view for furnace temperature measurements. The pyrometer includes a heterodyne millimeter/sub-millimeter-wave or microwave receiver including a millimeter/sub-millimeter-wave or microwave source for probing. The receiver is adapted to receive radiation from a surface whose temperature is to be measured. The radiation includes a surface emission portion and a surface reflection portion which includes the probe beam energy reflected from the surface. The surface emission portion is related to the surface temperature and the surface reflection portion is related to the emissivity of the surface. The simultaneous measurement of surface emissivity serves as a real time calibration of the temperature measurement. In an alternative embodiment, a translatable base plate and a visible laser beam allow slow mapping out of interference patterns and obtaining peak values therefor. The invention also includes a waveguide having a replaceable end portion, an insulating refractory sleeve and/or a source of inert gas flow. The pyrometer may be used in conjunction with a waveguide to form a system for temperature measurements in a furnace. The system may employ a chopper or alternatively, be constructed without a chopper. The system may also include an auxiliary reflector for surface emissivity measurements.

  3. Inverse analysis of inner surface temperature history from outer surface temperature measurement of a pipe

    International Nuclear Information System (INIS)

    Kubo, S; Ioka, S; Onchi, S; Matsumoto, Y

    2010-01-01

    When slug flow runs through a pipe, nonuniform and time-varying thermal stresses develop and there is a possibility that thermal fatigue occurs. Therefore it is necessary to know the temperature distributions and the stress distributions in the pipe for the integrity assessment of the pipe. It is, however, difficult to measure the inner surface temperature directly. Therefore establishment of the estimation method of the temperature history on inner surface of pipe is needed. As a basic study on the estimation method of the temperature history on the inner surface of a pipe with slug flow, this paper presents an estimation method of the temperature on the inner surface of a plate from the temperature on the outer surface. The relationship between the temperature history on the outer surface and the inner surface is obtained analytically. Using the results of the mathematical analysis, the inverse analysis method of the inner surface temperature history estimation from the outer surface temperature history is proposed. It is found that the inner surface temperature history can be estimated from the outer surface temperature history by applying the inverse analysis method, even when it is expressed by the multiple frequency components.

  4. Mold temperature measurement for glass-pressing processes

    International Nuclear Information System (INIS)

    Holman, R.A.

    1985-01-01

    The largest use of radiation thermometers within Corning Glass Works is for mold temperature measurement for the glass-pressing process. Pressing television panels at today's high quality would be very difficult without a mold temperature measurement system and the computer manipulation of the quality control data to supervise the mold temperature control loop. The most critical part of a television panel is the inside surface curvature. The ideal surface is usually defined as a spherical surface. The tolerance for a normal TV panel is +-0.30 mm (+-0.012 in.). High resolution display panels are more critical, having a dimensional tolerance only one half as large as TV panels. Panel curvature is a direct (but negative) function of mold temperature. Every 1 0 C increase in mold temperature results in the panel center being 0.025 mm (0.001 in.) shorter (flatter). Random dimensional variations within a panel take up most of the dimensional tolerance. The result is that each mold is controlled to its own individual temperature set point, +-1 0 C. Hot panel and cold panel curvature measurements are correlated by a process computer and used to update the mold temperature set points. The same computer adjusts the mold cooling air to maintain the required mold temperatures. From the temperature measurement standpoint, the significant problem is the changing emissivity of the mold surface when the mold is new or reconditioned. The selection of a radiation thermometer with a short wavelength was an obvious choice to minimize the effect of emissivity variations

  5. Comparison of elemental carbon in lake sediments measured by three different methods and 150-year pollution history in Eastern China.

    Science.gov (United States)

    Han, Y M; Cao, J J; Yan, B Z; Kenna, T C; Jin, Z D; Cheng, Y; Chow, Judith C; An, Z S

    2011-06-15

    Concentrations of elemental carbon (EC) were measured in a 150 yr sediment record collected from Lake Chaohu in Anhui Province, eastern China, using three different thermal analytical methods: IMPROVE_A thermal optical reflectance (TOR), STN_thermal optical transmittance (TOT), and chemothermal oxidation (CTO). Distribution patterns for EC concentrations are different among the three methods, most likely due to the operational definition of EC and different temperature treatments prescribed for each method. However, similar profiles were found for high-temperature EC fractions among different methods. Historical soot(TOR) (high-temperature EC fractions measured by the IMPROVE_A TOR method) from Lake Chaohu exhibited stable low concentrations prior to the late 1970s and a sharp increase thereafter, corresponding well with the rapid industrialization of China in the last three decades. This may suggest that high-temperature thermal protocols are suitable for differentiating between soot and other carbon fractions. A similar soot(TOR) record was also obtained from Lake Taihu (~200 km away), suggesting a regional source of soot. The ratio of char(TOR) (low-temperature EC fraction measured by the IMPROVE_A TOR method, after correction for pyrolysis) to soot(TOR) in Lake Chaohu shows an overall decreasing trend, consistent with gradual changes in fuel use from wood burning to increasing fossil fuel combustions. Average higher char(TOR)/soot(TOR) was observed in Lake Taihu than in Lake Chaohu in the past 150 years, consistent with the longer and more extensive industrialization around the Taihu region.

  6. Online junction temperature measurement using peak gate current

    DEFF Research Database (Denmark)

    Baker, Nick; Munk-Nielsen, Stig; Iannuzzo, Francesco

    2015-01-01

    A new method for junction temperature measurement of MOS-gated power semiconductor switches is presented. The measurement method involves detecting the peak voltage over the external gate resistor of an IGBT or MOSFET during turn-on. This voltage is directly proportional to the peak gate current...

  7. In-core moderator temperature measurement within candu reactors

    Science.gov (United States)

    Sion, N.

    1983-03-01

    The temperature profile of the D 2O moderator inside a CANDU (Canada Deuterium Uranium) reactor, within the calandria vessel, was measured by means of a specially instrumented probe introduced within the core. Measurements were made under steady and transient reactor conditions using two different sensors, viz. resistance temperature detectors (RTD) and type K chromel-alumel thermocouples. The results established the feasibility of in-core moderatortemperature measurement and indicated that the thermocouples used were relatively not affected by the intense radiation fields thus producing more accurate data.

  8. Space potential, temperature, and density profile measurements on RENTOR

    International Nuclear Information System (INIS)

    Schoch, P.M.

    1983-05-01

    Radial profiles of the space potential, electron temperature, and density have been measured on RENTOR with a heavy-ion-beam probe. The potential profile has been compared to predictions from a stochastic magnetic field fluctuation theory, using the measured temperature and density profiles. The comparison shows strong qualitative agreement in that the potential is positive and the order of T/sub e//e. There is some quantitative disagreement in that the measured radial electric fields are somewhat smaller than the theoretical predictions. To facilitate this comparison, a detailed analysis of the possible errors has been completed

  9. Innovative Instrumentation and Analysis of the Temperature Measurement for High Temperature Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Seong W. Lee

    2005-10-01

    The objectives of this project during this semi-annual reporting period are to test the effects of coating layer of the thermal couple on the temperature measurement and to screen out the significant factors affecting the temperature reading under different operational conditions. The systematic tests of the gasifier simulator on the high velocity oxygen fuel (HVOF) spray coated thermal couples were completed in this reporting period. The comparison tests of coated and uncoated thermal couples were conducted under various operational conditions. The temperature changes were recorded and the temperature differences were calculated to describe the thermal spray coating effect on the thermal couples. To record the temperature data accurately, the computerized data acquisition system (DAS) was adopted to the temperature reading. The DAS could record the data with the accuracy of 0.1 C and the recording parameters are configurable. In these experiments, DAS was set as reading one data for every one (1) minute. The operational conditions are the combination of three parameters: air flow rate, water/ammonia flow rate and the amount of fine dust particles. The results from the temperature readings show the temperature of uncoated thermal couple is uniformly higher than that of coated thermal couple for each operational condition. Analysis of Variances (ANOVA) was computed based on the results from systematic tests to screen out the significant factors and/or interactions. The temperature difference was used as dependent variable and three operational parameters (i.e. air flow rate, water/ammonia flow rate and amount of fine dust particle) were used as independent factors. The ANOVA results show that the operational parameters are not the statistically significant factors affecting the temperature readings which indicate that the coated thermal couple could be applied to temperature measurement in gasifier. The actual temperature reading with the coated thermal couple in

  10. Measurement of critical temperature as a function of field

    Science.gov (United States)

    McInturff, A. D.; Ishibashi, K.; Heard, G. D.

    The critical temperature has been measured for various magnet conductors as a function of the perpendicular applied magnetic field. The isothermal environment was provided by a variable temperature cryostat which fits into the bore of a 10 telsa solenoid. The temperature gradient across the sample volume was measured to be less than 25 millikelvins. The superconducting to normal state transition was measured resistively, using sample current densities from 0.01 to 2 A cm -2. The maximum applied magnetic field was 10 T and varied less than 0.5% in the sample volume. The critical transport current range of the samples measured from tens to thousands of amperes in the presence of a 10 T perpendicular magnetic field at 4.2 K.

  11. Measurement of rock properties at elevated pressures and temperatures

    International Nuclear Information System (INIS)

    Pincus, H.J.; Hoskins, E.R.

    1985-01-01

    The papers in this volume were presented at an ASTM symposium held on 20 June 1983 in conjunction with the 24th Annual Rock Mechanics Symposium at Texas A and M University, College Station, TX. The purpose of these papers is to present recent developments in the measurement of rock properties at elevated pressures and temperatures, and to examine and interpret the data produced by such measurement. The need for measuring rock properties at elevated pressures and temperatures has become increasingly important in recent years. Location and design of nuclear waste repositories, development of geothermal energy sites, and design and construction of deep excavations for civil, military, and mining engineering require significantly improved capabilities for measuring rock properties under conditions substantially different from those prevailing in most laboratory and in situ work. The development of high-pressure, high-temperature capabilities is also significant for the analysis of tectonic processes

  12. Surface temperature measurement of plasma facing components in tokamaks

    International Nuclear Information System (INIS)

    Amiel, Stephane

    2014-01-01

    During this PhD, the challenges on the non-intrusive surface temperature measurements of metallic plasma facing components in tokamaks are reported. Indeed, a precise material emissivity value is needed for classical infrared methods and the environment contribution has to be known particularly for low emissivities materials. Although methods have been developed to overcome these issues, they have been implemented solely for dedicated experiments. In any case, none of these methods are suitable for surface temperature measurement in tokamaks.The active pyrometry introduced in this study allows surface temperature measurements independently of reflected flux and emissivities using pulsed and modulated photothermal effect. This method has been validated in laboratory on metallic materials with reflected fluxes for pulsed and modulated modes. This experimental validation is coupled with a surface temperature variation induced by photothermal effect and temporal signal evolvement modelling in order to optimize both the heating source characteristics and the data acquisition and treatment. The experimental results have been used to determine the application range in temperature and detection wavelengths. In this context, the design of an active pyrometry system on tokamak has been completed, based on a bicolor camera for a thermography application in metallic (or low emissivity) environment.The active pyrometry method introduced in this study is a complementary technique of classical infrared methods used for thermography in tokamak environment which allows performing local and 2D surface temperature measurements independently of reflected fluxes and emissivities. (author) [fr

  13. Characterization and reactivity of soot from fast pyrolysis of lignocellulosic compounds and monolignols

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Brown, Avery; Tompsett, Geoffrey

    2018-01-01

    This study presents the effect of lignocellulosic compounds and monolignols on the yield, nanostructure and reactivity of soot generated at 1250 °C in a drop tube furnace. The structure of soot was characterized by electron microscopy techniques, Raman spectroscopy and electron spin resonance spe...... of the extraction solvent had a strong influence on the soot reactivity. The Soxhlet extraction of softwood and wheat straw lignin soot using methanol decreased the soot reactivity, whereas acetone extraction had only a modest effect....

  14. A Temperature Sensor using a Silicon-on-Insulator (SOI) Timer for Very Wide Temperature Measurement

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik; Culley, Dennis E.

    2008-01-01

    A temperature sensor based on a commercial-off-the-shelf (COTS) Silicon-on-Insulator (SOI) Timer was designed for extreme temperature applications. The sensor can operate under a wide temperature range from hot jet engine compartments to cryogenic space exploration missions. For example, in Jet Engine Distributed Control Architecture, the sensor must be able to operate at temperatures exceeding 150 C. For space missions, extremely low cryogenic temperatures need to be measured. The output of the sensor, which consisted of a stream of digitized pulses whose period was proportional to the sensed temperature, can be interfaced with a controller or a computer. The data acquisition system would then give a direct readout of the temperature through the use of a look-up table, a built-in algorithm, or a mathematical model. Because of the wide range of temperature measurement and because the sensor is made of carefully selected COTS parts, this work is directly applicable to the NASA Fundamental Aeronautics/Subsonic Fixed Wing Program--Jet Engine Distributed Engine Control Task and to the NASA Electronic Parts and Packaging (NEPP) Program. In the past, a temperature sensor was designed and built using an SOI operational amplifier, and a report was issued. This work used an SOI 555 timer as its core and is completely new work.

  15. Is Oral Temperature an Accurate Measurement of Deep Body Temperature? A Systematic Review

    Science.gov (United States)

    Mazerolle, Stephanie M.; Ganio, Matthew S.; Casa, Douglas J.; Vingren, Jakob; Klau, Jennifer

    2011-01-01

    Context: Oral temperature might not be a valid method to assess core body temperature. However, many clinicians, including athletic trainers, use it rather than criterion standard methods, such as rectal thermometry. Objective: To critically evaluate original research addressing the validity of using oral temperature as a measurement of core body temperature during periods of rest and changing core temperature. Data Sources: In July 2010, we searched the electronic databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTDiscus, Academic Search Premier, and the Cochrane Library for the following concepts: core body temperature, oral, and thermometers. Controlled vocabulary was used, when available, as well as key words and variations of those key words. The search was limited to articles focusing on temperature readings and studies involving human participants. Data Synthesis: Original research was reviewed using the Physiotherapy Evidence Database (PEDro). Sixteen studies met the inclusion criteria and subsequently were evaluated by 2 independent reviewers. All 16 were included in the review because they met the minimal PEDro score of 4 points (of 10 possible points), with all but 2 scoring 5 points. A critical review of these studies indicated a disparity between oral and criterion standard temperature methods (eg, rectal and esophageal) specifically as the temperature increased. The difference was −0.50°C ± 0.31°C at rest and −0.58°C ± 0.75°C during a nonsteady state. Conclusions: Evidence suggests that, regardless of whether the assessment is recorded at rest or during periods of changing core temperature, oral temperature is an unsuitable diagnostic tool for determining body temperature because many measures demonstrated differences greater than the predetermined validity threshold of 0.27°C (0.5°F). In addition, the differences were greatest at the highest rectal temperatures. Oral temperature cannot

  16. Temperature, its measurement and control in industry - ITM '90

    International Nuclear Information System (INIS)

    Fischer, H.; Blieck, L.; Jescheck, M.; Neubert, W.; Kunze, D.

    1990-01-01

    The publication refers to the new VDE/VDI guideline 3511 and explains its practical intentions and implications by thoroughly discussing the applications of temperature sensors and their limits of use. The current state of the art in temperature measuring is fully described by the discussion of the new temperature scale introduced recently, the ITS '90. The authors of the book look in detail at the particular requirements and conditions of infrared measuring techniques using radiation thermometers as defined in DIN 5496, the applications of microprocessors (DIN-measuring-field-bus, etc.), time program emitters, and measuring transducers (EX ib, etc.). A full chapter has been devoted to the subject of surface temperature measurement. Examples referring to practical applications in industry serve as an introduction to thermal control engineering, in particular with infrared sensors, for processes such as thermal forming. New, optical thermometers for the low temperature range have been given much attention. An annex presents comprehensive tables for calculation and conversion of thermal quantities. (orig./HP) With 192 figs., 134 refs [de

  17. High-temperature absorbed dose measurements in the megagray range

    International Nuclear Information System (INIS)

    Balian, P.; Ardonceau, J.; Zuppiroli, L.

    1988-01-01

    Organic conductors of the tetraselenotetracene family have been tested as ''high-temperature'' absorbed dose dosimeters. They were heated up to 120 0 C and irradiated at this temperature with 1-MeV electrons in order to simulate, in a short time, a much longer γ-ray irradiation. The electric resistance increase of the crystal can be considered a good measurement of the absorbed dose in the range 10 6 Gy to a few 10 8 Gy and presumably one order of magnitude more. This dosimeter also permits on-line (in-situ) measurements of the absorbed dose without removing the sensor from the irradiation site. The respective advantages of organic and inorganic dosimeters at these temperature and dose ranges are also discussed. In this connection, we outline new, but negative, results concerning the possible use of silica as a high-temperature, high-dose dosimeter. (author)

  18. Fuel centerline temperature measurement experiment in JMTR, 2

    International Nuclear Information System (INIS)

    Ando, Hiroei; Kawamura, Hiroshi; Sezaki, Katsuji; Komukai, Bunsaku

    1980-11-01

    Fuel centerline temperature measurement experiment which is the most fundamental for the LWR fuel safety study, is planned to conduct in JMTR using OWL-1 loop facility. Irradiation of the first test assembly was completed. In this paper, the comparison between measured fuel centerline temperature data and predicted ones by JAERI's FREG-4 code which is a computer program to calculate fuel temperature distribution is made. Furthermore, the data analysis method such as how to estimate local linear power and inpile behavior of the instrumentations are described. The maximum fuel center temperature was 1250 0 C at steady state, the maximum linear power was 320 W/cm, and the maximum burnup was about 1600 MWD/T. (author)

  19. Gas Temperature Measurement in a Glow Discharge Plasma

    Science.gov (United States)

    Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

    2009-10-01

    In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

  20. Measuring Skin Temperatures with the IASI Hyperspectral Mission

    Science.gov (United States)

    Safieddine, S.; George, M.; Clarisse, L.; Clerbaux, C.

    2017-12-01

    Although the role of satellites in observing the variability of the Earth system has increased in recent decades, remote-sensing observations are still underexploited to accurately assess climate change fingerprints, in particular temperature variations. The IASI - Flux and Temperature (IASI-FT) project aims at providing new benchmarks for temperature observations using the calibrated radiances measured twice a day at any location by the IASI thermal infrared instrument on the suite of MetOp satellites (2006-2025). The main challenge is to achieve the accuracy and stability needed for climate studies, particularly that required for climate trends. Time series for land and sea skin surface temperatures are derived and compared with in situ measurements and atmospheric reanalysis. The observed trends are analyzed at seasonal and regional scales in order to disentangle natural (weather/dynamical) variability and human-induced climate forcings.

  1. Prediction and measurement of selected phase transformation temperatures of steels

    Directory of Open Access Journals (Sweden)

    Martiník O.

    2017-01-01

    Full Text Available The study deals with precise determination of phase transformation temperatures of steel. A series of experimental measurements were carried out by Differential Thermal Analysis (DTA and Direct Thermal Analysis (TA to obtain temperatures very close to the equilibrium temperatures. There are presented results from the high temperatures region, above 1000°C, with focus on the solidus temperatures (TS, peritectic transition (TP and liquidus (TL of multicomponent steels. The data obtained were verified by statistical evaluation and compared with computational thermodynamic and empirical calculations. The calculations were performed using 15 empirical equations obtained by literature research (10 for TL and 5 for TS, as well as by software InterDendritic Solidification (IDS and Thermo-Calc (2015b, TCFE8; TC. It was verified that both thermo-analytical methods used are set correctly; the results are reproducible, comparable and close to equilibrium state.

  2. Time-averaged probability density functions of soot nanoparticles along the centerline of a piloted turbulent diffusion flame using a scanning mobility particle sizer

    KAUST Repository

    Chowdhury, Snehaunshu

    2017-01-23

    In this study, we demonstrate the use of a scanning mobility particle sizer (SMPS) as an effective tool to measure the probability density functions (PDFs) of soot nanoparticles in turbulent flames. Time-averaged soot PDFs necessary for validating existing soot models are reported at intervals of ∆x/D∆x/D = 5 along the centerline of turbulent, non-premixed, C2H4/N2 flames. The jet exit Reynolds numbers of the flames investigated were 10,000 and 20,000. A simplified burner geometry based on a published design was chosen to aid modelers. Soot was sampled directly from the flame using a sampling probe with a 0.5-mm diameter orifice and diluted with N2 by a two-stage dilution process. The overall dilution ratio was not evaluated. An SMPS system was used to analyze soot particle concentrations in the diluted samples. Sampling conditions were optimized over a wide range of dilution ratios to eliminate the effect of agglomeration in the sampling probe. Two differential mobility analyzers (DMAs) with different size ranges were used separately in the SMPS measurements to characterize the entire size range of particles. In both flames, the PDFs were found to be mono-modal in nature near the jet exit. Further downstream, the profiles were flatter with a fall-off at larger particle diameters. The geometric mean of the soot size distributions was less than 10 nm for all cases and increased monotonically with axial distance in both flames.

  3. Measuring temperature using MRI: a powerful and versatile technique.

    Science.gov (United States)

    Turner, Robert; Streicher, Markus

    2012-02-01

    The Larmor frequency of water protons has reliably linear temperature dependence. Since this frequency shift is easily measurable using relatively simple MRI techniques, a remarkable opportunity arises for uniquely non-invasive and accurate temperature evaluation, deep within any water-containing object. Major applications are appearing in the field of image-guided surgery. The cutting-edge papers collected in this Special Issue demonstrate both the versatility and the power of MRI thermometry.

  4. Reaction mechanism for the free-edge oxidation of soot by O 2

    KAUST Repository

    Raj, Abhijeet

    2012-11-01

    The reaction pathways for the oxidation by O 2 of polycyclic aromatic hydrocarbons present in soot particles are investigated using density functional theory at B3LYP/6-311++G(d,p) level of theory. For this, pyrene radical (4-pyrenyl) is chosen as the model molecule, as most soot models present in the literature employ the reactions involving the conversion of 4-pyrenyl to 4-phenanthryl by O 2 and OH to account for soot oxidation. Several routes for the formation of CO and CO 2 are proposed. The addition of O 2 on a radical site to form a peroxyl radical is found to be barrierless and exothermic with reaction energy of 188kJ/mol. For the oxidation reaction to proceed further, three pathways are suggested, each of which involve the activation energies of 104, 167 and 115kJ/mol relative to the peroxyl radical. The effect of the presence of H atom on a carbon atom neighboring the radical site on the energetics of carbon oxidation is assessed. Those intermediate species formed during oxidation with seven-membered rings or with a phenolic group are found to be highly stable. The rate constants evaluated using transition state theory in the temperature range of 300-3000K for the reactions involved in the mechanism are provided. © 2012 The Combustion Institute.

  5. Diamond micro-Raman thermometers for accurate gate temperature measurements

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Roland B.; Pomeroy, James W.; Kuball, Martin [Center for Device Thermography and Reliability, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

    2014-05-26

    Determining the peak channel temperature in AlGaN/GaN high electron mobility transistors and other devices with high accuracy is an important and challenging issue. A surface-sensitive thermometric technique is demonstrated, utilizing Raman thermography and diamond microparticles to measure the gate temperature. This technique enhances peak channel temperature estimation, especially when it is applied in combination with standard micro-Raman thermography. Its application to other metal-covered areas of devices, such as field plates is demonstrated. Furthermore, this technique can be readily applied to other material/device systems.

  6. Diamond micro-Raman thermometers for accurate gate temperature measurements

    International Nuclear Information System (INIS)

    Simon, Roland B.; Pomeroy, James W.; Kuball, Martin

    2014-01-01

    Determining the peak channel temperature in AlGaN/GaN high electron mobility transistors and other devices with high accuracy is an important and challenging issue. A surface-sensitive thermometric technique is demonstrated, utilizing Raman thermography and diamond microparticles to measure the gate temperature. This technique enhances peak channel temperature estimation, especially when it is applied in combination with standard micro-Raman thermography. Its application to other metal-covered areas of devices, such as field plates is demonstrated. Furthermore, this technique can be readily applied to other material/device systems.

  7. Containerless high temperature property measurements by atomic fluorescence

    Science.gov (United States)

    Schiffman, R. A.; Walker, C. A.

    1984-01-01

    Laser induced fluorescence (LIF) techniques for containerless study of high temperature processes and material properties was studied. Gas jet and electromagnetic levitation and electromagnetic and laser heating techniques are used with LIF in earth-based containerless high temperature experiments. Included are the development of an apparatus and its use in the studies of (1) chemical reactions on Al2O3, molybdenum, tungsten and LaB6 specimens, (2) methods for noncontact specimen temperature measurement, (3) levitation jet properties and (4) radiative lifetime and collisional energy transfer rates for electronically excited atoms.

  8. Study of Optical Fiber Sensors for Cryogenic Temperature Measurements

    Directory of Open Access Journals (Sweden)

    Veronica De Miguel-Soto

    2017-11-01

    Full Text Available In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg grating (FBG, and a π-phase shifted fiber Bragg grating interrogated in a random distributed feedback fiber laser have been studied. Their sensitivities and resolutions as sensors for cryogenic temperatures have been compared regarding their advantages and disadvantages. Additionally, the results have been compared with the given by a commercial optical backscatter reflectometer that allowed for distributed temperature measurements of a single mode fiber.

  9. Study of Optical Fiber Sensors for Cryogenic Temperature Measurements.

    Science.gov (United States)

    De Miguel-Soto, Veronica; Leandro, Daniel; Lopez-Aldaba, Aitor; Beato-López, Juan Jesus; Pérez-Landazábal, José Ignacio; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; Lopez-Amo, Manuel

    2017-11-30

    In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg grating (FBG), and a π-phase shifted fiber Bragg grating interrogated in a random distributed feedback fiber laser have been studied. Their sensitivities and resolutions as sensors for cryogenic temperatures have been compared regarding their advantages and disadvantages. Additionally, the results have been compared with the given by a commercial optical backscatter reflectometer that allowed for distributed temperature measurements of a single mode fiber.

  10. Temperature measurements in a wall stabilized steady flame using CARS

    KAUST Repository

    Sesha Giri, Krishna

    2017-01-05

    Flame quenching by heat loss to a surface continues to be an active area of combustion research. Close wall temperature measurements in an isothermal wall-stabilized flame are reported in this work. Conventional N-vibrational Coherent Anti-Stokes Raman Scattering (CARS) thermometry as close as 275 μm to a convex wall cooled with water has been carried out. The standard deviation of mean temperatures is observed to be ~6.5% for high temperatures (>2000K) and ~14% in the lower range (<500K). Methane/air and ethylene/air stoichiometric flames for various global strain rates based on exit bulk velocities are plotted and compared. CH* chemiluminescence is employed to determine the flame location relative to the wall. Flame locations are shown to move closer to the wall with increasing strain rates in addition to higher near-wall temperatures. Peak temperatures for ethylene are considerably higher (~250-300K) than peak temperatures for methane. Preheat zone profiles are similar for different strain rates across fuels. This work demonstrates close wall precise temperature measurments using CARS.

  11. Downhole temperature tool accurately measures well bore profile

    International Nuclear Information System (INIS)

    Cloud, W.B.

    1992-01-01

    This paper reports that an inexpensive temperature tool provides accurate temperatures measurements during drilling operations for better design of cement jobs, workovers, well stimulation, and well bore hydraulics. Valid temperature data during specific wellbore operations can improve initial job design, fluid testing, and slurry placement, ultimately enhancing well bore performance. This improvement applies to cement slurries, breaker activation for slurries, breaker activation for stimulation and profile control, and fluid rheological properties for all downhole operations. The temperature tool has been run standalone mounted inside drill pipe, on slick wire line and braided cable, and as a free-falltool. It has also been run piggyback on both directional surveys (slick line and free-fall) and standard logging runs. This temperature measuring system has been used extensively in field well bores to depths of 20,000 ft. The temperature tool is completely reusable in the field, ever similar to the standard directional survey tools used on may drilling rigs. The system includes a small, rugged, programmable temperature sensor, a standard body housing, various adapters for specific applications, and a personal computer (PC) interface

  12. [Comparison of different methods of temperature measurment in children].

    Science.gov (United States)

    Pavlović, Momcilo; Radlović, Nedeljko; Leković, Zoran; Berenji, Karolina

    2008-01-01

    The consequences of failing to notice fever in children can be serious. On the other hand, false positive reading can result in unnecesery investigation or diagnostic approach. The aim of this study was to compare different ways of body temperature measurement. This prospective study was carried out on Pediatric Department of General Hospital in Subotica during 10 months (March-December 2006). In 263 children aged 1 month to 18 years of age, the body temperature was obtained from 4 measurement sites: tactile assesment, forehead and ear by electronic thermometer, rectal temperature in small children (up to 2 years of age) or axillar temperature in older children by mercury thermometer. Tympanic thermometry was considered as a standard for fever detection. The sensitivity of rectal temperature to detect fever is 46.67%, while specificity is 92.19%. The sensitivity of fever detection by electronic thermometry on the forehead is lower according to rectal thermometry - 36.08%, while specificity is 95.18%. The lowest values ofsensitivity are recorded in axillar thermometry (35.82%), specificity is 90.20%. The correlation coefficient is higher between tympanic and rectal temperature measurement (r=0.5076, pchildren and tympanic thermometry in children over 2 years of age.

  13. A Phenomenological Model for Prediction Auto-Ignition and Soot Formation of Turbulent Diffusion Combustion in a High Pressure Common Rail Diesel Engine

    Directory of Open Access Journals (Sweden)

    Qinghui Zhou

    2011-06-01

    Full Text Available A new phenomenological model, the TP (Temperature Phase model, is presented to carry out optimization calculations for turbulent diffusion combustion in a high-pressure common rail diesel engine. Temperature is the most important parameter in the TP model, which includes two parts: an auto-ignition and a soot model. In the auto-ignition phase, different reaction mechanisms are built for different zones. For the soot model, different methods are used for different temperatures. The TP model is then implemented in KIVA code instead of original model to carry out optimization. The results of cylinder pressures, the corresponding heat release rates, and soot with variation of injection time, variation of rail pressure and variation of speed among TP model, KIVA standard model and experimental data are analyzed. The results indicate that the TP model can carry out optimization and CFD (computational fluid dynamics and can be a useful tool to study turbulent diffusion combustion.

  14. Numerical Investigation of Soot Formation in Non-premixed Flames

    KAUST Repository

    Abdelgadir, Ahmed Gamaleldin

    2017-05-01

    Soot is a carbon particulate formed as a result of the combustion of fossil fuels. Due to the health hazard posed by the carbon particulate, government agencies have applied strict regulations to control soot emissions from road vehicles, airplanes, and industrial plants. Thus, understanding soot formation and evolution is critical. Practical combustion devices operate at high pressure and in the turbulent regime. Elevated pressures and turbulence on soot formation significantly and fundamental understanding of these complex interactions is still poor. In this study, the effects of pressure and turbulence on soot formation and growth are investigated numerically. As the first step, the evolution of the particle size distribution function (PSDF) and soot particles morphology are investigated in turbulent non-premixed flames. A Direct Simulation Monte Carlo (DSMC) code is developed and used. The stochastic reactor describes the evolution of soot in fluid parcels following Lagrangian trajectories in a turbulent flow field. The trajectories are sampled from a Direct Numerical Simulation (DNS) of an n-heptane turbulent non-premixed flame. Although individual trajectories display strong bimodality as in laminar flames, the ensemble-average PSDF possesses only one mode and a broad tail, which implies significant polydispersity induced by turbulence. Secondly, the effect of the flow and mixing fields on soot formation at atmospheric and elevated pressures is investigated in coflow laminar diffusion flames. The experimental observation and the numerical prediction of the spatial distribution are in good agreement. Based on the common scaling methodology of the flames (keeping the Reynolds number constant), the scalar dissipation rate decreases as pressure increases, promoting the formation of PAH species and soot. The decrease of the scalar dissipation rate significantly contributes to soot formation occurring closer to the nozzle and outward on the flames wings as pressure

  15. Artefacts in intracavitary temperature measurements during regional hyperthermia

    International Nuclear Information System (INIS)

    Kok, H P; Berg, C A T Van den; Haaren, P M A Van; Crezee, J

    2007-01-01

    For adequate hyperthermia treatments, reliable temperature information during treatment is essential. During regional hyperthermia, temperature information is preferably obtained non-invasively from intracavitary or intraluminal measurements to avoid implant risks for the patient. However, for intracavitary or intraluminal thermometry optimal tissue contact is less natural as for invasive thermometry. In this study, the reliability of intraluminal/intracavitary measurements was examined in phantom experiments and in a numerical model for various extents of thermal contact between thermometry and the surroundings. Both thermocouple probes and fibre optic probes were investigated. Temperature rises after a 30 s power pulse of the 70 MHz AMC-4 hyperthermia system were measured in a tissue-equivalent phantom using a multisensor thermocouple probe placed centrally in a hollow tube. The tube was filled with (1) air (2) distilled water or (3) saline solution that mimics the properties of tissue, simulating situations with (1) bad thermal contact and no power dissipation in the tube (2) good thermal contact but no power dissipation or (3) good thermal contact and tissue representative power dissipation. For numerical simulations, a cylindrical symmetric model of a thermocouple probe or a fibre optic probe in a cavity was developed. The cavity was modelled as air, distilled water or saline solution. A generalised E-Field distribution was assumed, resulting in a power deposition. With this power deposition, the temperature rise after a 30 s power pulse was calculated. When thermal contact was bad (1), both phantom measurements and simulations with a thermocouple probe showed very high temperature rises (>0.5 0 C), which are artefacts due to self-heating of the thermocouple probe, since no power is dissipated in air. Simulations with a fibre optic probe showed almost no temperature rise when the cavity was filled with air. When thermal contact was good, but no power was

  16. Reconstructing bottom water temperatures from measurements of temperature and thermal diffusivity in marine sediments

    Science.gov (United States)

    Miesner, F.; Lechleiter, A.; Müller, C.

    2015-07-01

    Continuous monitoring of oceanic bottom water temperatures is a complicated task, even in relatively easy-to-access basins like the North or Baltic seas. Here, a method to determine annual bottom water temperature variations from inverse modeling of instantaneous measurements of temperatures and sediment thermal properties is presented. This concept is similar to climate reconstructions over several thousand years from deep borehole data. However, in contrast, the presented method aims at reconstructing the recent temperature history of the last year from sediment thermal properties and temperatures from only a few meters depth. For solving the heat equation, a commonly used forward model is introduced and analyzed: knowing the bottom water temperature variations for the preceding years and the thermal properties of the sediments, the forward model determines the sediment temperature field. The bottom water temperature variation is modeled as an annual cosine defined by the mean temperature, the amplitude and a phase shift. As the forward model operator is non-linear but low-dimensional, common inversion schemes such as the Newton algorithm can be utilized. The algorithms are tested for artificial data with different noise levels and for two measured data sets: from the North Sea and from the Davis Strait. Both algorithms used show stable and satisfying results with reconstruction errors in the same magnitude as the initial data error. In particular, the artificial data sets are reproduced with accuracy within the bounds of the artificial noise level. Furthermore, the results for the measured North Sea data show small variances and resemble the bottom water temperature variations recorded from a nearby monitoring site with relative errors smaller than 1 % in all parameters.

  17. Sensitive Dependence of Gibbs Measures at Low Temperatures

    Science.gov (United States)

    Coronel, Daniel; Rivera-Letelier, Juan

    2015-09-01

    The Gibbs measures of an interaction can behave chaotically as the temperature drops to zero. We observe that for some classical lattice systems there are interactions exhibiting a related phenomenon of sensitive dependence of Gibbs measures: An arbitrarily small perturbation of the interaction can produce significant changes in the low-temperature behavior of its Gibbs measures. For some one-dimensional XY models we exhibit sensitive dependence of Gibbs measures for a (nearest-neighbor) interaction given by a smooth function, and for perturbations that are small in the smooth category. We also exhibit sensitive dependence of Gibbs measures for an interaction on a classical lattice system with finite-state space. This interaction decreases exponentially as a function of the distance between sites; it is given by a Lipschitz continuous potential in the configuration space. The perturbations are small in the Lipschitz topology. As a by-product we solve some problems stated by Chazottes and Hochman.

  18. Electron Tomography of Nanoparticle Clusters: Implications for Atmospheric Lifetimes and Radiative Forcing of Soot

    Science.gov (United States)

    vanPoppel, Laura H.; Friedrich, Heiner; Spinsby, Jacob; Chung, Serena H.; Seinfeld, John H.; Buseck, Peter R.

    2005-01-01

    Nanoparticles are ubiquitous in nature. Their large surface areas and consequent chemical reactivity typically result in their aggregation into clusters. Their chemical and physical properties depend on cluster shapes, which are commonly complex and unknown. This is the first application of electron tomography with a transmission electron microscope to quantitatively determine the three-dimensional (3D) shapes, volumes, and surface areas of nanoparticle clusters. We use soot (black carbon, BC) nanoparticles as an example because it is a major contributor to environmental degradation and global climate change. To the extent that our samples are representative, we find that quantitative measurements of soot surface areas and volumes derived from electron tomograms differ from geometrically derived values by, respectively, almost one and two orders of magnitude. Global sensitivity studies suggest that the global burden and direct radiative forcing of fractal BC are only about 60% of the value if it is assumed that BC has a spherical shape.

  19. Estimation of piping temperature fluctuations based on external strain measurements

    International Nuclear Information System (INIS)

    Morilhat, P.; Maye, J.P.

    1993-01-01

    Due to the difficulty to carry out measurements at the inner sides of nuclear reactor piping subjected to thermal transients, temperature and stress variations in the pipe walls are estimated by means of external thermocouples and strain-gauges. This inverse problem is solved by spectral analysis. Since the wall harmonic transfer function (response to a harmonic load) is known, the inner side signal will be obtained by convolution of the inverse transfer function of the system and of the strain measurement enables detection of internal temperature fluctuations in a frequency range beyond the scope of the thermocouples. (authors). 5 figs., 3 refs

  20. Temperature dependence of the Brewer global UV measurements

    Science.gov (United States)

    Fountoulakis, Ilias; Redondas, Alberto; Lakkala, Kaisa; Berjon, Alberto; Bais, Alkiviadis F.; Doppler, Lionel; Feister, Uwe; Heikkila, Anu; Karppinen, Tomi; Karhu, Juha M.; Koskela, Tapani; Garane, Katerina; Fragkos, Konstantinos; Savastiouk, Volodya

    2017-11-01

    Spectral measurements of global UV irradiance recorded by Brewer spectrophotometers can be significantly affected by instrument-specific optical and mechanical features. Thus, proper corrections are needed in order to reduce the associated uncertainties to within acceptable levels. The present study aims to contribute to the reduction of uncertainties originating from changes in the Brewer internal temperature, which affect the performance of the optical and electronic parts, and subsequently the response of the instrument. Until now, measurements of the irradiance from various types of lamps at different temperatures have been used to characterize the instruments' temperature dependence. The use of 50 W lamps was found to induce errors in the characterization due to changes in the transmissivity of the Teflon diffuser as it warms up by the heat of the lamp. In contrast, the use of 200 or 1000 W lamps is considered more appropriate because they are positioned at longer distances from the diffuser so that warming is negligible. Temperature gradients inside the instrument can cause mechanical stresses which can affect the instrument's optical characteristics. Therefore, during the temperature-dependence characterization procedure warming or cooling must be slow enough to minimize these effects. In this study, results of the temperature characterization of eight different Brewer spectrophotometers operating in Greece, Finland, Germany and Spain are presented. It was found that the instruments' response changes differently in different temperature regions due to different responses of the diffusers' transmittance. The temperature correction factors derived for the Brewer spectrophotometers operating at Thessaloniki, Greece, and Sodankylä, Finland, were evaluated and were found to remove the temperature dependence of the instruments' sensitivity.

  1. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  2. Response to Comment on “Modeling Maximum Adsorption Capacities of Soot and Soot-like Materials for PAHs and PCBs”

    NARCIS (Netherlands)

    Noort, van P.C.M.; Jonker, M.T.O.; Koelmans, A.A.

    2005-01-01

    A comment by John C. Fetzer on modeling maximum adsorption capacities of soot and soot-like materials for PAH and PCB and the adsorption behavior of PAH on soots and on other adsorptive materials is presented. The authors (van Noort et al.) base their model on van der Waal's forces only. This may be

  3. Fundamental insight in soot oxidation over a Ag/Co3O4 catalyst by means of Environmental TEM

    DEFF Research Database (Denmark)

    Gardini, Diego; Christiansen, J. M.; Jensen, Anker Degn

    to minimize the filter regeneration temperature – ideally down to the normal temperature of the exhaust gas - a new catalyst for soot oxidation consisting of Ag nanoparticles supported on Co3O4 has been synthesized using flame spray pyrolysis and characterized using electron microscopy and X-Ray diffraction...

  4. Core-temperature sensor ingestion timing and measurement variability.

    Science.gov (United States)

    Domitrovich, Joseph W; Cuddy, John S; Ruby, Brent C

    2010-01-01

    Telemetric core-temperature monitoring is becoming more widely used as a noninvasive means of monitoring core temperature during athletic events. To determine the effects of sensor ingestion timing on serial measures of core temperature during continuous exercise. Crossover study. Outdoor dirt track at an average ambient temperature of 4.4°C ± 4.1°C and relative humidity of 74.1% ± 11.0%. Seven healthy, active participants (3 men, 4 women; age  =  27.0 ± 7.5 years, height  =  172.9 ± 6.8 cm, body mass  =  67.5 ± 6.1 kg, percentage body fat  =  12.7% ± 6.9%, peak oxygen uptake [Vo(2peak)]  =  54.4 ± 6.9 mL•kg⁻¹•min⁻¹) completed the study. Participants completed a 45-minute exercise trial at approximately 70% Vo(2peak). They consumed core-temperature sensors at 24 hours (P1) and 40 minutes (P2) before exercise. Core temperature was recorded continuously (1-minute intervals) using a wireless data logger worn by the participants. All data were analyzed using a 2-way repeated-measures analysis of variance (trial × time), Pearson product moment correlation, and Bland-Altman plot. Fifteen comparisons were made between P1 and P2. The main effect of time indicated an increase in core temperature compared with the initial temperature. However, we did not find a main effect for trial or a trial × time interaction, indicating no differences in core temperature between the sensors (P1  =  38.3°C ± 0.2°C, P2  =  38.3°C ± 0.4°C). We found no differences in the temperature recordings between the 2 sensors. These results suggest that assumed sensor location (upper or lower gastrointestinal tract) does not appreciably alter the transmission of reliable and repeatable measures of core temperature during continuous running in the cold.

  5. Real-time temperature field measurement based on acoustic tomography

    International Nuclear Information System (INIS)

    Bao, Yong; Jia, Jiabin; Polydorides, Nick

    2017-01-01

    Acoustic tomography can be used to measure the temperature field from the time-of-flight (TOF). In order to capture real-time temperature field changes and accurately yield quantitative temperature images, two improvements to the conventional acoustic tomography system are studied: simultaneous acoustic transmission and TOF collection along multiple ray paths, and an offline iteration reconstruction algorithm. During system operation, all the acoustic transceivers send modulated and filtered wideband Kasami sequences simultaneously to facilitate fast and accurate TOF measurements using cross-correlation detection. For image reconstruction, the iteration process is separated and executed offline beforehand to shorten computation time for online temperature field reconstruction. The feasibility and effectiveness of the developed methods are validated in the simulation study. The simulation results demonstrate that the proposed method can reduce the processing time per frame from 160 ms to 20 ms, while the reconstruction error remains less than 5%. Hence, the proposed method has great potential in the measurement of rapid temperature change with good temporal and spatial resolution. (paper)

  6. Photoacoustic temperature measurements for monitoring of thermal therapy

    Science.gov (United States)

    Wang, Shiou-Han; Wei, Chen-Wei; Jee, Shiou-Hwa; Li, Pai-Chi

    2009-02-01

    Plasmonic photothermal therapy is a new cancer thermotherapy method based on surface plasmon resonance of nanoparticles. It is important to measure the temperature during thermotherapy for safety and efficacy. In this study, we apply a photoacoustic (PA) method for real-time, non-invasive temperature measurements. In particular, this method can be effectively combined with a photothermal therapy system that we developed in parallel. The method is based on the fact that the PA pressure amplitude is linearly related to temperature. To explore its potential, a home-made, 20 MHz PA transducer was used, in which an optical fiber was inserted in its center for emitting laser pulses while the PA signal was simultaneously detected. Continuous wave (CW) laser was used to heat the subject, including both phantoms and mice. The temperature of the region of interest was also measured by a fine-needle thermal couple. Results show that the temperature was linearly proportional to the PA signal with good correlation with the CW laser irradiation. The in vivo study also demonstrated potential of this technique.

  7. Constituent Ion Temperatures Measured in the Topside Ionosphere

    Science.gov (United States)

    Hsu, C. T.; Heelis, R. A.

    2017-12-01

    Plasma temperatures in the ionosphere are associated with both the dynamics and structure of the neutral and charge particles. The temperatures are determined by solar energy inputs and energy exchange between charged particles and neutrals. Previous observations show that during daytime the O+ temperature is generally higher when the fractional contribution of H+ to the plasma is high. Further simulations confirm that the daytime heat balance between the H+ and O+ always keeps the H+ at a temperature higher than the O+. In addition the plasma transport parallel and perpendicular to the magnetic field influences the plasma temperature through adiabatic heating and cooling effects. These processes are also important during the nighttime, when the source of photoionization is absent. In this work we examine a more sophisticated analysis procedure to extract individual mass dependent ion temperature and apply it on the DMSP F15 RPA measurements. The result shows that the daytime TH+ is a few hundred degrees higher than the TO+ and the nighttime temperature difference between TH+ and TO+ is indicative of mass dependent adiabatic heating and cooling processes across the equatorial region.

  8. On Possibility of Detonation Products Temperature Measurements of Emulsion Explosives

    Directory of Open Access Journals (Sweden)

    Silvestrov V. V.

    2014-10-01

    Full Text Available The new view on the structure of the radiance signal recorded by optical pyrometer and the preliminary results of brightness detonation temperature of the emulsion explosive are presented. The structure of an optical signal observed is typical for the heterogeneous explosives. First, there is the short temperature spike to 2500 ÷ 3300 K connecting with a formation of “hot spots” assembly that fire the matrix capable of exothermal reaction. Then the relaxation of radiance to equilibrium level is observed that corresponds to brightness temperature 1840 ÷ 2260 K of explosion products at detonation pressure 1 ÷ 11 GPa. Experimental results are compared with the calculations of other authors. The detonation temperature of the investigated explosive is measured for the first time.

  9. CARS Temperature Measurements in a Combustion-Heated Supersonic Jet

    Science.gov (United States)

    Tedder, S. A.; Danehy, P. M.; Magnotti, G.; Cutler, A. D.

    2009-01-01

    Measurements were made in a combustion-heated supersonic axi-symmetric free jet from a nozzle with a diameter of 6.35 cm using dual-pump Coherent Anti-Stokes Raman Spectroscopy (CARS). The resulting mean and standard deviation temperature maps are presented. The temperature results show that the gas temperature on the centerline remains constant for approximately 5 nozzle diameters. As the heated gas mixes with the ambient air further downstream the mean temperature decreases. The standard deviation map shows evidence of the increase of turbulence in the shear layer as the jet proceeds downstream and mixes with the ambient air. The challenges of collecting data in a harsh environment are discussed along with influences to the data. The yield of the data collected is presented and possible improvements to the yield is presented are discussed.

  10. A lidar system for measuring atmospheric pressure and temperature profiles

    Science.gov (United States)

    Schwemmer, Geary K.; Dombrowski, Mark; Korb, C. Laurence; Milrod, Jeffry; Walden, Harvey

    1987-01-01

    The design and operation of a differential absorption lidar system capable of remotely measuring the vertical structure of tropospheric pressure and temperature are described. The measurements are based on the absorption by atmospheric oxygen of the spectrally narrowband output of two pulsed alexandrite lasers. Detailed laser output spectral characteristics, which are critical to successful lidar measurements, are presented. Spectral linewidths of 0.026 and 0.018 per cm for the lasers were measured with over 99.99 percent of the energy contained in three longitudinal modes.

  11. Electrical measurement of absolute temperature and temperature transients in a buried nanostructure under ultrafast optical heating

    Science.gov (United States)

    Yang, H. F.; Hu, X. K.; Liebing, N.; Böhnert, T.; Costa, J. D.; Tarequzzaman, M.; Ferreira, R.; Sievers, S.; Bieler, M.; Schumacher, H. W.

    2017-06-01

    We report absolute temperature measurements in a buried nanostructure with a sub-nanosecond temporal resolution. For this purpose, we take advantage of the temperature dependence of the resistance of a magnetic tunnel junction (MTJ) as detected by a fast sampling oscilloscope. After calibrating the measurement setup using steady-state electric heating, we are able to quantify temperature changes in the MTJ induced by femtosecond optical heating of the metal contact lying several 100 nm above the MTJ. We find that a femtosecond pulse train with an average power of 400 mW and a repetition rate of 76 MHz leads to a constant temperature increase of 80 K and a temporally varying temperature change of 2 K in the MTJ. The maximum temperature change in the MTJ occurs 4 ns after the femtosecond laser pulses hit the metal contact, which is supported by simulations. Our work provides a scheme to quantitatively study local temperatures in nanoscale structures and might be important for the testing of nanoscale thermal transport simulations.

  12. Comparison of MODIS-derived land surface temperature with air temperature measurements

    Science.gov (United States)

    Georgiou, Andreas; Akçit, Nuhcan

    2017-09-01

    Air surface temperature is an important parameter for a wide range of applications such as agriculture, hydrology and climate change studies. Air temperature data is usually obtained from measurements made in meteorological stations, providing only limited information about spatial patterns over wide areas. The use of remote sensing data can help overcome this problem, particularly in areas with low station density, having the potential to improve the estimation of air surface temperature at both regional and global scales. Land Surface (skin) Temperatures (LST) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra and Aqua satellite platforms provide spatial estimates of near-surface temperature values. In this study, LST values from MODIS are compared to groundbased near surface air (Tair) measurements obtained from 14 observational stations during 2011 to 2015, covering coastal, mountainous and urban areas over Cyprus. Combining Terra and Aqua LST-8 Day and Night acquisitions into a mean monthly value, provide a large number of LST observations and a better overall agreement with Tair. Comparison between mean monthly LSTs and mean monthly Tair for all sites and all seasons pooled together yields a very high correlation and biases. In addition, the presented high standard deviation can be explained by the influence of surface heterogeneity within MODIS 1km2 grid cells, the presence of undetected clouds and the inherent difference between LST and Tair. However, MODIS LST data proved to be a reliable proxy for surface temperature and mostly for studies requiring temperature reconstruction in areas with lack of observational stations.

  13. Infrared thermography for temperature measurement and non-destructive testing.

    Science.gov (United States)

    Usamentiaga, Rubén; Venegas, Pablo; Guerediaga, Jon; Vega, Laura; Molleda, Julio; Bulnes, Francisco G

    2014-07-10

    The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed.

  14. Estimating local heat transfer coefficients from thin wall temperature measurements

    Science.gov (United States)

    Gazizov, I. M.; Davletshin, I. A.; Paereliy, A. A.

    2017-09-01

    An approach to experimental estimation of local heat transfer coefficient on a plane wall has been described. The approach is based on measurements of heat-transfer fluid and wall temperatures during some certain time of wall cooling. The wall was a thin plate, a printed circuit board, made of composite epoxy material covered with a copper layer. The temperature field can be considered uniform across the plate thickness when heat transfer is moderate and thermal resistance of the plate in transversal direction is low. This significantly simplifies the heat balance written for the wall sections that is used to estimate the heat transfer coefficient. The copper layer on the plate etched to form a single strip acted as resistance thermometers that measured the local temperature of the wall.

  15. Measured energy savings from using night temperature setback

    International Nuclear Information System (INIS)

    Szydlowski, R.F.; Wrench, L.E.; O'Neill, P.J.

    1993-01-01

    The measured energy savings resulting from using night temperature setback in typical light-construction wooden office buildings was determined. Researchers installed monitoring equipment in a six-building sample of two-story wooden buildings at Fort Devens, Massachusetts. Data obtained during both single-setting and night-setback operating modes were used to develop models of each building's heat consumption as a function of the difference between inside and outside temperature. These models were used to estimate seasonal savings that could be obtained from the use of night-setback thermostat control. The measured savings in heating energy from using night temperature setback for the six Fort Devens buildings ranged from 14% to 25%; the mean savings was 19.2%. Based on an energy cost of $0.65/therm of natural gas, the estimated average cost savings of using automatic setback thermostats in these buildings is $780 per year per building

  16. Infrared Thermography for Temperature Measurement and Non-Destructive Testing

    Science.gov (United States)

    Usamentiaga, Rubèn; Venegas, Pablo; Guerediaga, Jon; Vega, Laura; Molleda, Julio; Bulnes, Francisco G.

    2014-01-01

    The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed. PMID:25014096

  17. Infrared Thermography for Temperature Measurement and Non-Destructive Testing

    Directory of Open Access Journals (Sweden)

    Rubén Usamentiaga

    2014-07-01

    Full Text Available The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed.

  18. Parametrization of optimum filter passbands for rotational Raman temperature measurements.

    Science.gov (United States)

    Hammann, Eva; Behrendt, Andreas

    2015-11-30

    We revisit the methodology of rotational Raman temperature measurements covering both lidar and non-range-resolved measurements, e.g., for aircraft control. The results of detailed optimization calculations are presented for the commonly used extraction of signals from the anti-Stokes branch. Different background conditions and realistic shapes of the filter transmission curves are taken into account. Practical uncertainties of the central passbands and widths are discussed. We found a simple parametrization for the optimum filter passband shifts depending on the atmospheric temperature range of interest and the background. The approximation errors of this parametrization are smaller than 2% for temperatures between 200 and 300 K and smaller than 4% between 180 and 200 K.

  19. Ultra sound absorption measurements in rock samples at low temperatures

    Science.gov (United States)

    Herminghaus, C.; Berckhemer, H.

    1974-01-01

    A new technique, comparable with the reverberation method in room acoustics, is described. It allows Q-measurements at rock samples of arbitrary shape in the frequency range of 50 to 600 kHz in vacuum (.1 mtorr) and at low temperatures (+20 to -180 C). The method was developed in particular to investigate rock samples under lunar conditions. Ultrasound absorption has been measured at volcanics, breccia, gabbros, feldspar and quartz of different grain size and texture yielding the following results: evacuation raises Q mainly through lowering the humidity in the rock. In a dry compact rock, the effect of evacuation is small. With decreasing temperature, Q generally increases. Between +20 and -30 C, Q does not change much. With further decrease of temperature in many cases distinct anomalies appear, where Q becomes frequency dependent.

  20. Temperature Measurements of Dense Plasmas by Detailed Balance

    International Nuclear Information System (INIS)

    Holl, A; Redmer, R; Ropke, G; Reinholz, H; Thiele, R; Fortmann, C; Forster, E; Cao, L; Tschentscher, T; Toleikis, S; Glenzer, S H

    2006-01-01

    Plasmas at high electron densities of n e = 10 20 - 10 26 cm -3 and moderate temperatures T e = 1 - 20 eV are important for laboratory astrophysics, high energy density science and inertial confinement fusion. These plasmas are usually referred to as Warm Dense Matter (WDM) and are characterized by a coupling parameter of Λ ∼> 1 where correlations become important. The characterization of such plasmas is still a challenging task due to the lack of direct measurement techniques for temperatures and densities. They propose to measure the Thomson scattering spectrum of vacuum-UV radiation off density fluctuations in the plasma. Collective Thomson scattering provides accurate data for the electron temperature applying first principles. Further, this method takes advantage of the spectral asymmetry resulting from detailed balance and is independent of collisional effects in these dense systems

  1. A Measurement of the Cosmic Microwave Background Temperature ...

    Indian Academy of Sciences (India)

    tribpo

    •calibrating the contributions from the feed assembly and receiver. The thermodynamic temperature of the CMB is estimated to be. 3.45 ± 0.78 K. Key words. Cosmic microwave background — cosmology: observations. 1. Introduction. The spectrum of the cosmic microwave background (CMB) has been measured by the.

  2. Tokamak Plasmas: Measurement of temperature fluctuations and ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Pramana – Journal of Physics; Volume 55; Issue 5-6. Tokamak Plasmas : Measurement of temperature fluctuations and anomalous transport in the SINP tokamak. R Kumar S K Saha. Contributed Papers Volume 55 Issue 5-6 November-December 2000 pp ...

  3. Measurements of plasma temperature and electron density in laser

    Indian Academy of Sciences (India)

    The temperature and electron density characterizing the plasma are measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time window of 300–2000 ns. An echelle spectrograph coupled with a gated intensified charge coupled detector is used to record the plasma emissions.

  4. Elevated-temperature luminescence measurements to improve spatial resolution

    Science.gov (United States)

    Pluska, Mariusz; Czerwinski, Andrzej

    2018-01-01

    Various branches of applied physics use luminescence based methods to investigate light-emitting specimens with high spatial resolution. A key problem is that luminescence signals lack all the advantages of high locality (i.e. of high spatial resolution) when structures with strong built-in electric field are measured. Such fields exist intentionally in most photonic structures, and occur unintentionally in many other materials. In this case, as a result of beam-induced current generation and its outflow, information that indicates irregularities, nonuniformities and inhomogeneities, such as defects, is lost. We show that to avoid nonlocality and enable truly local luminescence measurements, an elevated measurement temperature as high as 350 K (or even higher) is, perhaps surprisingly, advantageous. This is in contrast to a widely used approach, where cryogenic temperatures, or at least room temperature, are recommended. The elevated temperature of a specimen, together with the current outflow being limited by focused ion beam (FIB) milling, is shown to improve the spatial resolution of luminescence measurements greatly. All conclusions drawn using the example of cathodoluminescence are useful for other luminescence techniques.

  5. Measurements of plasma temperature and electron density in laser ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 74; Issue 6. Measurements of plasma temperature and electron density in laser-induced copper plasma by time-resolved spectroscopy of neutral atom and ion emissions. V K Unnikrishnan Kamlesh Alti V B Kartha C Santhosh G P Gupta B M Suri. Research Articles ...

  6. Effects of non-unity Lewis number of gas-phase species in turbulent nonpremixed sooting flames

    KAUST Repository

    Attili, Antonio

    2016-02-13

    Turbulence statistics from two three-dimensional direct numerical simulations of planar n-heptane/air turbulent jets are compared to assess the effect of the gas-phase species diffusion model on flame dynamics and soot formation. The Reynolds number based on the initial jet width and velocity is around 15, 000, corresponding to a Taylor scale Reynolds number in the range 100 ≤ Reλ ≤ 150. In one simulation, multicomponent transport based on a mixture-averaged approach is employed, while in the other the gas-phase species Lewis numbers are set equal to unity. The statistics of temperature and major species obtained with the mixture-averaged formulation are very similar to those in the unity Lewis number case. In both cases, the statistics of temperature are captured with remarkable accuracy by a laminar flamelet model with unity Lewis numbers. On the contrary, a flamelet with a mixture-averaged diffusion model, which corresponds to the model used in the multi-component diffusion three-dimensional DNS, produces significant differences with respect to the DNS results. The total mass of soot precursors decreases by 20-30% with the unity Lewis number approximation, and their distribution is more homogeneous in space and time. Due to the non-linearity of the soot growth rate with respect to the precursors\\' concentration, the soot mass yield decreases by a factor of two. Being strongly affected by coagulation, soot number density is not altered significantly if the unity Lewis number model is used rather than the mixture-averaged diffusion. The dominant role of turbulent transport over differential diffusion effects is expected to become more pronounced for higher Reynolds numbers. © 2016 The Combustion Institute.

  7. Radon measurements with charcoal canisters temperature and humidity considerations

    Directory of Open Access Journals (Sweden)

    Živanović Miloš Z.

    2016-01-01

    Full Text Available Radon testing by using open-faced charcoal canisters is a cheap and fast screening method. Many laboratories perform the sampling and measurements according to the United States Environmental Protection Agency method - EPA 520. According to this method, no corrections for temperature are applied and corrections for humidity are based on canister mass gain. The EPA method is practiced in the Vinča Institute of Nuclear Sciences with recycled canisters. In the course of measurements, it was established that the mass gain of the recycled canisters differs from mass gain measured by Environmental Protection Agency in an active atmosphere. In order to quantify and correct these discrepancies, in the laboratory, canisters were exposed for periods of 3 and 4 days between February 2015 and December 2015. Temperature and humidity were monitored continuously and mass gain measured. No significant correlation between mass gain and temperature was found. Based on Environmental Protection Agency calibration data, functional dependence of mass gain on humidity was determined, yielding Environmental Protection Agency mass gain curves. The results of mass gain measurements of recycled canisters were plotted against these curves and a discrepancy confirmed. After correcting the independent variable in the curve equation and calculating the corrected mass gain for recycled canisters, the agreement between measured mass gain and Environmental Protection Agency mass gain curves was attained. [Projekat Ministarstva nauke Republike Srbije, br. III43009: New Technologies for Monitoring and Protection of Environment from Harmful Chemical Substances and Radiation Impact

  8. Fiber-optical method of pyrometric measurement of melts temperature

    Science.gov (United States)

    Zakharenko, V. A.; Veprikova, Ya R.

    2018-01-01

    There is a scientific problem of non-contact measurement of the temperature of metal melts now. The problem is related to the need to achieve the specified measurement errors in conditions of uncertainty of the blackness coefficients of the radiating surfaces. The aim of this work is to substantiate the new method of measurement in which the influence of the blackness coefficient is eliminated. The task consisted in calculating the design and material of special crucible placed in the molten metal, which is an emitter in the form of blackbody (BB). The methods are based on the classical concepts of thermal radiation and calculations based on the Planck function. To solve the problem, the geometry of the crucible was calculated on the basis of the Goofy method which forms the emitter of a blackbody at the immersed in the melt. The paper describes the pyrometric device based on fiber optic pyrometer for temperature measurement of melts, which implements the proposed method of measurement using a special crucible. The emitter is formed by the melt in this crucible, the temperature within which is measured by means of fiber optic pyrometer. Based on the results of experimental studies, the radiation coefficient ε‧ > 0.999, which confirms the theoretical and computational justification is given in the article

  9. Innovative Instrumentation and Analysis of the Temperature Measurement for High Temperature Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Seong W. Lee

    2006-09-30

    The project entitled, ''Innovative Instrumentation and Analysis of the Temperature Measurement for High Temperature Gasification'', was successfully completed by the Principal Investigator, Dr. S. Lee and his research team in the Center for Advanced Energy Systems and Environmental Control Technologies at Morgan State University. The major results and outcomes were presented in semi-annual progress reports and annual project review meetings/presentations. Specifically, the literature survey including the gasifier temperature measurement, the ultrasonic application in cleaning application, and spray coating process and the gasifier simulator (cold model) testing has been successfully conducted during the first year. The results show that four factors (blower voltage, ultrasonic application, injection time intervals, particle weight) were considered as significant factors that affect the temperature measurement. Then the gasifier simulator (hot model) design and the fabrication as well as the systematic tests on hot model were completed to test the significant factors on temperature measurement in the second year. The advanced Industrial analytic methods such as statistics-based experimental design, analysis of variance (ANOVA) and regression methods were applied in the hot model tests. The results show that operational parameters (i.e. air flow rate, water flow rate, fine dust particle amount, ammonia addition) presented significant impact on the temperature measurement inside the gasifier simulator. The experimental design and ANOVA are very efficient way to design and analyze the experiments. The results show that the air flow rate and fine dust particle amount are statistically significant to the temperature measurement. The regression model provided the functional relation between the temperature and these factors with substantial accuracy. In the last year of the project period, the ultrasonic and subsonic cleaning methods and coating

  10. Thin-film resistance temperature detector array for the measurement of temperature distribution inside a phantom

    Science.gov (United States)

    Sim, Jai Kyoung; Hyun, Jaeyub; Doh, Il; Ahn, Bongyoung; Kim, Yong Tae

    2018-02-01

    A thin-film resistance temperature detector (RTD) array is proposed to measure the temperature distribution inside a phantom. HIFU (high-intensity focused ultrasound) is a non-invasive treatment method using focused ultrasound to heat up a localized region, so it is important to measure the temperature distribution without affecting the ultrasonic field and heat conduction. The present 25 µm thick PI (polyimide) film is transparent not only to an ultrasonic field, because its thickness is much smaller than the wavelength of ultrasound, but also to heat conduction, owing to its negligible thermal mass compared to the phantom. A total of 33 RTDs consisting of Pt resistors and interconnection lines were patterned on a PI substrate using MEMS (microelectromechanical systems) technology, and a polymer phantom was fabricated with the film at the center. The expanded uncertainty of the RTDs was 0.8 K. In the experimental study using a 1 MHz HIFU transducer, the maximum temperature inside the phantom was measured as 70.1 °C just after a HIFU excitation of 6.4 W for 180 s. The time responses of the RTDs at different positions also showed the residual heat transfer inside the phantom after HIFU excitation. HIFU results with the phantom showed that a thin-film RTD array can measure the temperature distribution inside a phantom.

  11. Core Temperature Measurement During Submaximal Exercise: Esophageal, Rectal, and Intestinal Temperatures

    Science.gov (United States)

    Lee, Stuart M. C.; Williams, W. Jon; Schneider, Suzanne M.

    2000-01-01

    The purpose of this study was to determine if intestinal temperature (Tin) might be in acceptable alternative to esophageal (Tes) and rectal temperature (Trec) to assess thermoregulation during supine exercise. We hypothesized that Tin would have values similar to Tes and a response time similar to Trec, but the rate of temperature change across time would not be different between measurement sites. Seven subjects completed a continuous supine protocol of 20 min of rest, 20 min of cycle exercise at 40% peak oxygen consumption (VO2pk), 20 min of cycle exercise at 65% V02pk, and 20 min of recovery. Tes, Trec, and Tin were recorded each min throughout the test. Temperatures were not different after 20 min of rest, but Trec was less than the Tes and Tin at the end of the 40% and 65% VO2pk stages. After 20 min of recovery, Tes was less than either Trec or Tin, which were not different from each other. Time to threshold for increased temperature from rest was greater for Trec than Tes but not different from Tin. Time to reach peak temperature was greater for Tin and Trec than Tes. Similarly, time to a decrease in temperature after exercise was greater for Trec than Tes, but not different from Tin. The rate of temperature change from threshold to the end of the 40% VO2pk stage was not different between measurement sites. However, the rate of change during recovery was more negative for Tes than Tin and Trec, which were different from each other. Measurement of Tin may he an acceptable alternative to Tes and Trec with an understanding of its limitations.

  12. A comparison of four methods of normal newborn temperature measurement.

    Science.gov (United States)

    Sganga, A; Wallace, R; Kiehl, E; Irving, T; Witter, L

    2000-01-01

    The purpose of this study was to: (a) compare newborn temperature measurements obtained by digital disposable, electronic, and tympanic thermometers with glass mercury thermometers, and (b) compare financial implications of each method. In this correlational study, 12 perinatal and neonatal nurses obtained temperature measurements of 184 newborns between 1 and 168 hours of age. The stratified convenience sample was selected using medical records numbers. Temperature instruments included glass thermometer, tympanic thermometer, electronic thermometer, and a digital thermometer. Data were analyzed by Pearson r coefficients, mean, standard deviation, and range using an SPSS statistical package. The glass thermometer, electronic thermometer, and digital thermometer temperature assessments were highly correlated (0.748-1.0). The tympanic thermometer had a low correlation coefficient (0.35). Use of the glass thermometer had the highest accompanying cost. Tympanic thermometers were the most cost effective. In healthy newborns, the use of electronic and digital thermometers can be encouraged if there is concern about using glass thermometers. These results cannot be extrapolated to sick infants. While tympanic thermometers had the lowest associated cost, their lack of correlation with the gold standard glass thermometers for accurate temperature assessment makes them a poor choice for healthy newborns.

  13. Importance of the oxygen bond strength for catalytic activity in soot oxidation

    DEFF Research Database (Denmark)

    Christensen, Jakob M.; Grunwaldt, Jan-Dierk; Jensen, Anker D.

    2016-01-01

    energies for soot oxidation follow linear Brønsted-Evans-Polanyi relationships with the heat of oxygen chemisorption. Among the tested metal or metal oxide catalysts Co3O4 and CeO2 were nearest to the optimal bond strength in tight contact oxidation, while Cr2O3 was nearest to the optimum in loose contact......The oxygen bond strength on a catalyst, as measured by the heat of oxygen chemisorption, is observed to be a very important parameter for the activity of the catalyst in soot oxidation. With both intimate contact between soot and catalyst (tight contact) and with the solids stirred loosely together...... oxidation. The optimum of the volcano curve in loose contact is estimated to occur between the bond strengths of α-Fe2O3 and α-Cr2O3. Guided by an interpolation principle FeaCrbOx binary oxides were tested, and the activity of these oxides was observed to pass through an optimum for an FeCr2Ox binary oxide...

  14. Effect of soot on oil properties and wear of engine components

    International Nuclear Information System (INIS)

    Green, D A; Lewis, R

    2007-01-01

    The objective of the work outlined in this paper was to increase the understanding of the wear mechanisms that occur within a soot contaminated contact zone, to help in future development of a predictive wear model to assist in the automotive engine valve train design process. The paper builds on previous work by the author, through testing of different lubricants and increased levels of soot contamination. Wear testing has been carried out using specimens operating under realistic engine conditions, using a reciprocating test-rig specifically designed for this application, where a steel disc is held in a heated bath of oil and a steel ball is attached to a reciprocating arm (replicating a sliding elephant's foot valve train contact). Detailed analysis of the test specimens has been performed using scanning electron microscopy to identify wear features relating to the proposed wear mechanisms. Analysis of worn engine components from durability engine tests has also been carried out for a comparison between specimen tests and engine testing. To assist the understanding of the wear test results obtained, the physical properties of contaminated lubricants were investigated, through viscosity, traction and friction measurements. The results have revealed how varying lubrication conditions change the wear rate of engine components and determine the wear mechanism that dominates in specific situations. Testing has also shown the positive effects of advanced engine lubricants to reduce the amount of wear produced with soot present

  15. Effect of soot on oil properties and wear of engine components

    Science.gov (United States)

    Green, D. A.; Lewis, R.

    2007-09-01

    The objective of the work outlined in this paper was to increase the understanding of the wear mechanisms that occur within a soot contaminated contact zone, to help in future development of a predictive wear model to assist in the automotive engine valve train design process. The paper builds on previous work by the author, through testing of different lubricants and increased levels of soot contamination. Wear testing has been carried out using specimens operating under realistic engine conditions, using a reciprocating test-rig specifically designed for this application, where a steel disc is held in a heated bath of oil and a steel ball is attached to a reciprocating arm (replicating a sliding elephant's foot valve train contact). Detailed analysis of the test specimens has been performed using scanning electron microscopy to identify wear features relating to the proposed wear mechanisms. Analysis of worn engine components from durability engine tests has also been carried out for a comparison between specimen tests and engine testing. To assist the understanding of the wear test results obtained, the physical properties of contaminated lubricants were investigated, through viscosity, traction and friction measurements. The results have revealed how varying lubrication conditions change the wear rate of engine components and determine the wear mechanism that dominates in specific situations. Testing has also shown the positive effects of advanced engine lubricants to reduce the amount of wear produced with soot present.

  16. Directional radiometric measurements of row-crop temperatures

    Science.gov (United States)

    Kimes, D. S.; Kirchner, J. A.

    1983-01-01

    The variability of directional sensor response for a cotton row crop in Phoenix, Arizona was measured for various solar zenith angles. The geometric structure of the canopy was described with regard to height, width, spacing, and shape of rows. In addition, radiometric temperature data were collected on four scene components: sunlit and shaded vegetation and sunlit and shaded soil. These data were used to test the predictions and assumptions of a modified version of the row crop model of Jackson et al. (1979), which predicts the thermal infrared response of a sensor as a function of sensor view angle, component temperature, and geometrical structure of the canopy. The field data showed sensor response differentials as great as 16.2 C when going from a zenith view angle of 0 deg to one of 80 deg normal to the row direction. The rms deviation between the predicted and measured sensor response for all measurement periods and view angles was 0.96 C.

  17. Thermal conductivity measurements at cryogenic temperatures at LASA

    International Nuclear Information System (INIS)

    Broggi, F.; Pedrini, D.; Rossi, L.

    1995-08-01

    Here the improvement realised to have better control of the reference junction temperature and measurements carried out on Nb 3 Sn cut out from 2 different coils (named LASA3 and LASA5), showing the difference between the longitudinal and the transverse thermal conductivity, is described. Two different methods of data analysis are presented, the DAM (derivative approximated method) and the TCI (thermal conductivity integral. The data analysis for the tungsten and the LASA5 coil has been done according to the two methods showing that the TCI method with polynomial functions is not adequate to describe the thermal conductivity. Only a polynomial fit based on the TCI method but limited at a lower order than the nominal, when the data are well distributed along the range of measurements, can describe reasonably the thermal conductivity dependence with the temperature. Finally the measurements on a rod of BSCCO 2212 high T c superconductor are presented

  18. Temperature Measurement in WTE Boilers Using Suction Pyrometers

    Directory of Open Access Journals (Sweden)

    Fabio Rinaldi

    2013-11-01

    Full Text Available The temperature of the flue-gas in the post combustion zone of a waste to energy (WTE plant has to be maintained within a fairly narrow range of values, the minimum of which is prescribed by the European Waste Directive 2000/76/CE, whereas the maximum value must be such as to ensure the preservation of the materials and the energy efficiency of the plant. A high degree of accuracy in measuring and controlling the aforementioned temperature is therefore required. In almost the totality of WTE plants this measurement process is carried out by using practical industrial thermometers, such as bare thermocouples and infrared radiation (IR pyrometers, even if affected by different physical contributions which can make the gas temperature measurements incorrect. The objective of this paper is to analyze errors and uncertainties that can arise when using a bare thermocouple or an IR pyrometer in a WTE plant and to provide a method for the in situ calibration of these industrial sensors through the use of suction pyrometers. The paper describes principle of operation, design, and uncertainty contributions of suction pyrometers, it also provides the best estimation of the flue-gas temperature in the post combustion zone of a WTE plant and the estimation of its expanded uncertainty.

  19. Temperature measurement in WTE boilers using suction pyrometers.

    Science.gov (United States)

    Rinaldi, Fabio; Najafi, Behzad

    2013-11-15

    The temperature of the flue-gas in the post combustion zone of a waste to energy (WTE) plant has to be maintained within a fairly narrow range of values, the minimum of which is prescribed by the European Waste Directive 2000/76/CE, whereas the maximum value must be such as to ensure the preservation of the materials and the energy efficiency of the plant. A high degree of accuracy in measuring and controlling the aforementioned temperature is therefore required. In almost the totality of WTE plants this measurement process is carried out by using practical industrial thermometers, such as bare thermocouples and infrared radiation (IR) pyrometers, even if affected by different physical contributions which can make the gas temperature measurements incorrect. The objective of this paper is to analyze errors and uncertainties that can arise when using a bare thermocouple or an IR pyrometer in a WTE plant and to provide a method for the in situ calibration of these industrial sensors through the use of suction pyrometers. The paper describes principle of operation, design, and uncertainty contributions of suction pyrometers, it also provides the best estimation of the flue-gas temperature in the post combustion zone of a WTE plant and the estimation of its expanded uncertainty.

  20. Pyrometric method for measuring emittances at high temperatures

    Science.gov (United States)

    Ballestrín, J.; Rodríguez, J.; Carra, M. E.; Cañadas, I.; Roldan, M. I.; Barbero, J.; Marzo, A.

    2016-05-01

    In this work an alternative method for emittance determination based on pyrometric measurements is presented. The measurement procedure has been applied to AISI 310S steel samples in the Plataforma Solar de Almería vertical axis solar furnace SF5. The experimental results show that emittance increases with increasing temperature and decreases with increasing wavelength. This behaviour is in agreement with experimental results obtained by other authors. Analysis of tests has revealed a good repeatability (1%) and accuracy (< 2%) of this measurement procedure.

  1. Electron temperature measurement of tungsten inert gas arcs

    International Nuclear Information System (INIS)

    Tanaka, Manabu; Tashiro, Shinichi

    2008-01-01

    In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs, the region where a deviation from LTE occurs tends to expand in higher arc current because the plasma reaches the similar state to LTE within shorter distance from the cathode due to the slower cathode jet velocity

  2. A Mueller bridge set for cryogenic temperature measurements

    DEFF Research Database (Denmark)

    Diamond, J.M.

    1966-01-01

    An a.c. Mueller bridge set for resistance thermometry at cryogenic temperature is described. A commercial tuned null detector is used at an operating frequency of 1025 c/s. The set includes a high stability oscillator, line reject filter, phase shifter, Q multiplier and selector box. The latter...... permits the dissipation in the thermometers not being measured to be maintained at the operating level with direct current. A temperature change of the order of 10 μdegK can be detected with 10-8 W applied to the thermometer....

  3. A sensitive optical pyrometer for shock-temperature measurements

    Science.gov (United States)

    Boslough, M. B.; Ahrens, T. J.

    1984-01-01

    A new optical system was used to determine temperatures above 2400 K in shocked materials by measuring the spectral radiance of sub-microsecond pulses of light emitted from initially transparent solid samples in the visible and near infrared (450 to 900 nm). The high sensitivity of this optical pyrometer is attributed to the small number of channels, large aperture (0.03 steradian), the large bandwidth per channel (40 nm), and large photodiode detection area (0.2 sq cm). Improved calibration techniques reduce systematic errors encountered in previous shock-temperature experiments.

  4. Experimental determination of soot refractive index in the infrared

    International Nuclear Information System (INIS)

    Ouf, F.X.; Vendel, J.; Ouf, F.X.; Coppalle, A.; Weil, M.E.; Yon, J.

    2007-01-01

    The study of physical properties of soot particles produced during combustion is a complex subject but of a great interest within the framework of the study of the safety of an installation, with respect to the fire hazard. These characteristics are, in this case, particularly useful in order to predict the behaviour of containment barriers in situation of fire, but also in order to estimate the contribution of these particles to radiative transfers. The aim of this study is to determine the radiative properties of soot particles produced during combustion. A specific device, which establishes extinction and vertical-vertical scattering coefficients, has been developed and has allowed to determine the refractive index of soot particles in the infrared. This determination also needed the establishment of size distribution and morphological properties of soot aggregates. We present in this document the experimental device developed, and the validation of this device on latex spheres which optical properties are well known. First results of extinction coefficients will be presented and will underline the similar optical behaviour of different soot aggregates. Values of refractive index will be detailed and discussed, and a direct application of these values will be carried out in order to determine the soot volume fraction. A comparison with reference method will underline the efficiency of our method. We will conclude on the validity of the information brought by this device and on the prospects of this study. A discussion is included, on the utility of mean values of refractive index and on the determination of total emissivity of soot particles. (authors)

  5. Determining noncondensible gas fractions at elevated temperatures and pressures using wet and dry bulb temperature measurements

    International Nuclear Information System (INIS)

    Griffith, P.; Bowman, J.

    1987-01-01

    The work reported in this note was undertaken to provide a method of determining the noncondensible gas fractions in a steam-gas mixture such as might be found in large reactor safety experiment like LOFT. In essence, the method used involves measuring the wet and dry bulb temperatures and using an algorithm, in place of the psychometric chart, to determine the partial pressure of the noncondensible gas in the mixture. In accomplishing this, the authors did the following: (1) extended the use of wet and dry-bulb temperature readings to determine mixture composition up to a temperature of 589 K and a pressure of 4.13 x 10 6 Pa. (2) developed an algorithm to reduce the data (3) found which materials would survive those temperatures

  6. Initial Neutral Particle Analyzer Measurements of Ion Temperature in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    S.S. Medley; R.E. Bell; M.P. Petrov; A.L. Roquemore; and E.V. Suvorkin

    2002-07-08

    The Neutral Particle Analyzer (NPA) diagnostic on the National Spherical Torus Experiment (NSTX) utilizes a PPPL-designed E||B spectrometer which measures the energy spectra of minority H and bulk D species simultaneously with 39 energy channels per mass specie and a time resolution of 1 msec. The calibrated energy range is E = 0.5-150 keV and the energy resolution varies from (delta)E/E = 3-7% over the surface of the microchannel plate detector. The NPA measures thermal Maxwellian ion spectra to obtain line integrated ion temperatures, T{sub i}. For line integral electron densities below neL {approx} 3.5 x 10{sup 19} m{sup -2}, good agreement is observed between the line integrated NPA T{sub i} and the central T{sub i}(0) measured by the spatially localized CHarge Exchange Recombination Spectroscopy (CHERS) diagnostic. However, with increasingly higher n{sub eL} the NPA T{sub i} falls below the central T{sub i}(0) measured by CHERS because the charge exchange neutral emissivity weights the line integrated NPA measurement outboard of the plasma core. An analytic neutral analysis code, DOUBLE, has been applied to the NPA data to correct for this effect and restore agreement with T{sub i}(0) measured by CHERS. A description of the NPA diagnostic on NSTX and initial ion temperature measurements along with an illustration of application of the DOUBLE code are presented.

  7. INNOVATIVE INSTRUMENTATION AND ANALYSIS OF THE TEMPERATURE MEASUREMENT FOR HIGH TEMPERATURE GASIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Seong W. Lee

    2003-09-01

    During this reporting period, the literature survey including the gasifier temperature measurement literature, the ultrasonic application and its background study in cleaning application, and spray coating process are completed. The gasifier simulator (cold model) testing has been successfully conducted. Four factors (blower voltage, ultrasonic application, injection time intervals, particle weight) were considered as significant factors that affect the temperature measurement. The Analysis of Variance (ANOVA) was applied to analyze the test data. The analysis shows that all four factors are significant to the temperature measurements in the gasifier simulator (cold model). The regression analysis for the case with the normalized room temperature shows that linear model fits the temperature data with 82% accuracy (18% error). The regression analysis for the case without the normalized room temperature shows 72.5% accuracy (27.5% error). The nonlinear regression analysis indicates a better fit than that of the linear regression. The nonlinear regression model's accuracy is 88.7% (11.3% error) for normalized room temperature case, which is better than the linear regression analysis. The hot model thermocouple sleeve design and fabrication are completed. The gasifier simulator (hot model) design and the fabrication are completed. The system tests of the gasifier simulator (hot model) have been conducted and some modifications have been made. Based on the system tests and results analysis, the gasifier simulator (hot model) has met the proposed design requirement and the ready for system test. The ultrasonic cleaning method is under evaluation and will be further studied for the gasifier simulator (hot model) application. The progress of this project has been on schedule.

  8. Use of aluminum nitride to obtain temperature measurements in a high temperature and high radiation environment

    Science.gov (United States)

    Wernsman, Bernard R.; Blasi, Raymond J.; Tittman, Bernhard R.; Parks, David A.

    2016-04-26

    An aluminum nitride piezoelectric ultrasonic transducer successfully operates at temperatures of up to 1000.degree. C. and fast (>1 MeV) neutron fluencies of more than 10.sup.18 n/cm.sup.2. The transducer comprises a transparent, nitrogen rich aluminum nitride (AlN) crystal wafer that is coupled to an aluminum cylinder for pulse-echo measurements. The transducer has the capability to measure in situ gamma heating within the core of a nuclear reactor.

  9. Temperature Measurement Technique Using Phosphorescence of Porphyrin Dyes

    Science.gov (United States)

    Kura, Kentaro; Someya, Satoshi; Okamoto, Koji

    2007-11-01

    LIF have been developed to measure the temperature, pH and the oxygen concentration in the fluid. However, the frequent excitation of the fluorescent dye causes the quenching effect. In addition, two color LIF should be applied in order to cancel the effect of non-uniform light intensity of excitation. The phosphor emitting the phosphorescence for a few milliseconds by an excitation was measured at the high time resolution, while the phosphorescence lifetime is the function of the temperature. As the phosphorescence dyes, PtTFPP and PdTFPP were tested. Those mixed with Coumarin30 were also demonstrated. These dyes were excited by a CW laser with the wavelength of 405nm. As the result, it was clarified to be able to measure the temperature using these dyes and this laser. Present study is the result of ``High speed three-dimensional direct measurement technology development for the evaluation of heat flux and flow of liquid metal'' entrusted to the University of Tokyo by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).

  10. The contribution of tyre and brake abrasion to soot levels in streets; Beitrag des Reifen- und Bremsenabriebs zur Russemission an Strassen

    Energy Technology Data Exchange (ETDEWEB)

    Rauterberg-Wulff, A.

    1998-09-01

    After the coming into force of the new soot emission thresholds as of July 1998, excess values are measured along many city streets. The author investigated whether tyre and brake abrasion contributes to soot emissions in addition to diesel soot. For this purpose, characteristic material and physical parameters of particles of diesel soot, tyre and brake material were investigated by thermography, AAS, and SEM. With the aid of a receptor-oriented approach, the contribution of these particles to soot levels measured in a highway tunnel and a Berlin city street could be assessed. The contribution of local traffic was calculated from the difference between soot levels along the road and in a background station. The measurements inside the tunnel served to determine emissin factors for diesel soot and abrasion particles from tyres and brakes. (orig.) [Deutsch] Mit Inkrafttreten des endgueltigen Russ-Immissionswertes der 23. Verordnung zum Bundes-Immissionsschutzgesetz im Juli 1998 ist an zahlreichen innerstaedtischen Strassen mit einer Ueberschreitung dieser Werte zu rechnen. Zur Beantwortung der Frage, inwieweit neben Dieselruss auch Reifen- und Bremsenabrieb zur verkehrsbedingten Russimmission beitragen, wurden charakteristische stoffliche und physikalische Eigenschaften von Dieselruss, Reifenabrieb und Bremsenabrieb mit der Thermographie, der AAS und der Rasterelektronenmikroskopie untersucht. Mit Hilfe dieses rezeptororientierten Ansatzes konnte der Beitrag dieser Partikel zur Russimmission in einem Autobahntunnel und an einer Hauptverkehrsstrasse in Berlin bestimmt werden, wobei zuerst der Beitrag des lokalen Verkehrs zur Russimmission aus der Differenz zwischen der Russimmission an der Strassen- und einer Hintergrundstation berechnet wurde. Mit Hilfe der Messungen im Tunnel konnten Emissionsfaktoren fuer Dieselruss und fuer Reifen- und Bremsenabriebpartikel bestimmt werden. (orig.)

  11. Methods of Temperature and Emission Measure Determination of Coronal Loops

    Science.gov (United States)

    Cirtain, J. W.; Schmelz, J. T.; Martens, P. C. H.

    2002-05-01

    Recent observational results from both SOHO-EIT and TRACE indicate that coronal loops are isothermal along their length (axially). These results are obtained from a narrowband filter ratio method that assumes that the plasma is isothermal along the line of sight (radially). However, these temperatures vary greatly from those derived from differential emission measure (DEM) curves produced from spectral lines recorded by SOHO-CDS. The DEM results indicate that the loops are neither axially nor radially isothermal. This discrepancy was investigated by Schmelz et al. (2001). They chose pairs of iron lines from the same CDS data set to mimic the EIT and TRACE loop results. Ratios of different lines gave different temperatures, indicating that the plasma was not radially isothermal. In addition the results indicated that the loop was axially isothermal, even though the DEM analysis of the same data showed this result to be false. Here we have analyzed the EIT data for the CDS loop published by Schmelz et al. (2001). We took the ratios of the 171-to-195 and 195-to-284 filter data, and made temperature maps of the loop. The results indicate that the loop is axially isothermal, but different temperatures were found for each pair of filters. Both ratio techniques force the resultant temperature to lie within the range where the response functions (for filters) or the emissivity functions (for lines) overlap; isothermal loops are therefore a byproduct of the analysis. This conclusion strengthens support for the idea that temperature and emission measure results from filter ratio methods may be misleading or even drastically wrong. This research was funded in part by the NASA/TRACE MODA grant for Montana State University. Solar physics research at the University of Memphis is supported by NASA grant NAG5-9783.

  12. Measuring core body temperature with a non-invasive sensor.

    Science.gov (United States)

    Mazgaoker, Savyon; Ketko, Itay; Yanovich, Ran; Heled, Yuval; Epstein, Yoram

    2017-05-01

    In various occupations, workers may be exposed to extreme environmental conditions and physical activities. Under these conditions the ability to follow the workers' body temperature may protect them from overheating that may lead to heat related injuries. The "Dräger" Double Sensor (DS) is a novel device for assessing body-core temperature (T c ). The purpose of this study was to evaluate the accuracy of the DS in measuring T c under heat stress. Seventeen male participants performed a three stage protocol: 30min rest in a thermal comfort environment (20-22°C, 50% relative humidity), followed by an exposure to a hot environment of 40°C, 40% relative humidity -30min at rest and 60min of exercise (walking on a treadmill at 5km/h and 2% elevation). Simultaneously temperatures measured by the DS (T DS ) and by rectal temperature (T re ) (YSI-401 thermistor) were recorded and then compared. During the three stages of the study the average temperature obtained by the DS was within±0.3°C of rectal measurement. The correlation between T DS and T re was significantly better during the heat exposures phases than during resting under comfort conditions. These preliminary results are promising for potential use of the DS by workers under field conditions and especially under environmental heat stress or when dressed in protective garments. For this goal, further investigations are required to validate the accuracy of the DS under various levels of heat stress, clothing and working levels. Copyright © 2017. Published by Elsevier Ltd.

  13. Measured Performance of a Low Temperature Air Source Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R. K. [Johnson Research LLC, Pueblo West, CO (United States)

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  14. Temperature measurement on neurological pulse generators during MR scans

    Directory of Open Access Journals (Sweden)

    Alesch François

    2002-09-01

    Full Text Available Abstract According to manufacturers of both magnetic resonance imaging (MRI machines, and implantable neurological pulse generators (IPGs, MRI is contraindicated for patients with IPGs. A major argument for this restriction is the risk to induce heat in the leads due to the electromagnetic field, which could be dangerous for the surrounding brain parenchyma. The temperature change on the surface of the case of an ITREL-III (Medtronic Inc., Minneapolis, MN and the lead tip during MRI was determined. An anatomical realistic and a cubic phantom, filled with phantom material mimicking human tissue, and a typical lead configuration were used to imitate a patient who carries an IPG for deep brain stimulation. The measurements were performed in a 1.5 T and a 3.0 T MRI. 2.1°C temperature increases at the lead tip uncovered the lead tip as the most critical part concerning heating problems in IPGs. Temperature increases in other locations were low compared to the one at the lead tip. The measured temperature increase of 2.1°C can not be considered as harmful to the patient. Comparison with the results of other studies revealed the avoidance of loops as a practical method to reduce heating during MRI procedures.

  15. Hybrid-type temperature sensor for in situ measurement

    Science.gov (United States)

    Iuchi, Tohru; Hiraka, Kensuke

    2006-11-01

    A hybrid-type surface temperature sensor combines the contact and noncontact methods, which allows us to overcome the shortcomings of both methods. The hybrid-type surface thermometer is composed mainly of two components: a metal film sheet that makes contact with an object and a radiometer that is used to detect the radiance of the rear surface of the metal film, which is actually a modified radiation thermometer. Temperature measurement using the hybrid-type thermometer with a several tens micrometer thick Hastelloy sheet, a highly heat and corrosion resistant alloy, is possible with a systematic error of -0.5K and random errors of ±0.5K, in the temperature range from 900to1000K. This thermometer provides a useful means for calibration of in situ temperature measurement in various processes, especially in the silicon semiconductor industry. This article introduces the basic idea of the hybrid-type surface sensor, presents experimental results and discussions, and finally describes some applications.

  16. Comparison Testings between Two High-temperature Strain Measurement Systems

    Science.gov (United States)

    Lei, J.-F.; Castelli, M. G.; Androjna, D.; Blue, C.; Blue, R.; Lin, R. Y.

    1996-01-01

    An experimental evaluation was conducted at NASA Lewis Research Center to compare and contrast the performance of a newly developed resistance strain gage, the PdCr temperature-compensated wire strain gage, to that of a conventional high-temperature extensometry. The evaluation of the two strain measurement systems was conducted through the application of various thermal and mechanical loading spectra using a high-temperature thermomechanical uniaxial testing system equipped with quartz lamp heating. The purpose of the testing was not only to compare and contrast the two strain sensors but also to investigate the applicability of the PdCr strain gage to the testing environment typically employed when characterizing the high-temperature mechanical behavior of structural materials. Strain measurement capabilities to 8OO C were investigated with a nickel base superalloy IN100 substrate material, and application to titanium matrix composite (TMC) materials was examined with the SCS-6/Ti-15-3 08 system. PdCr strain gages installed by three attachment techniques, namely, flame spraying, spot welding and rapid infrared joining were investigated.

  17. Comprehensive Laser-induced Incandescence (LII) modeling for soot particle sizing

    KAUST Repository

    Lisanti, Joel

    2015-03-30

    To evaluate the current state of the art in LII particle sizing, a comprehensive model for predicting the temporal incandescent response of combustion-generated soot to absorption of a pulsed laser is presented. The model incorporates particle heating through laser absorption, thermal annealing, and oxidation at the surface as well as cooling through sublimation and photodesorption, radiation, conduction and thermionic emission. Thermodynamic properties and the thermal accommodation coefficient utilized in the model are temperature dependent. In addition, where appropriate properties are also phase dependent, thereby accounting for annealing effects during laser heating and particle cooling.

  18. Measurement of Laser Weld Temperatures for 3D Model Input

    Energy Technology Data Exchange (ETDEWEB)

    Dagel, Daryl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grossetete, Grant [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Maccallum, Danny O. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    Laser welding is a key joining process used extensively in the manufacture and assembly of critical components for several weapons systems. Sandia National Laboratories advances the understanding of the laser welding process through coupled experimentation and modeling. This report summarizes the experimental portion of the research program, which focused on measuring temperatures and thermal history of laser welds on steel plates. To increase confidence in measurement accuracy, researchers utilized multiple complementary techniques to acquire temperatures during laser welding. This data serves as input to and validation of 3D laser welding models aimed at predicting microstructure and the formation of defects and their impact on weld-joint reliability, a crucial step in rapid prototyping of weapons components.

  19. High temperature elastic constant measurements: application to plutonium

    International Nuclear Information System (INIS)

    Bouchet, J.M.

    1969-03-01

    We present an apparatus with which we have measured the Young's modulus and the Poisson's ratio of several compounds from the resonance frequency of cylinders in the temperature range 0 deg. C-700 deg. C. We especially studied the elastic constants of plutonium and measured for the first time to our knowledge the Young's modulus of Pu δ and Pu ε . E δ 360 deg. C = 1.6 10 11 dy/cm 2 ; E ε 490 deg. C = 1.1 10 11 dy/cm 2 , σ ε = 0.25 ± 0.03 Using our results, we have calculated the compressibility, the Debye temperature, the Grueneisen constant and the electronic specific heat of Pu ε . (author) [fr

  20. Dual purpose pyrometer for temperature and solidification velocity measurement

    Science.gov (United States)

    Hofmeister, W. H.; Bayuzick, R. J.; Robinson, M. B.

    1990-01-01

    A dual purpose pyrometer is described that allows both accurate radiance temperature measurement and fast temporal response. The system uses two silicon photodiodes with separate optical paths derived from a common spot on the sample. The optical bandwidths and response times of each detection circuit are tailored to the function of each radiometer. The radiance temperature of electromagnetically levitated metallic samples is measured over a narrow optical bandwidth with a high-gain silicon detector. The velocity of solidification of undercooled melts can be deduced from the rise time of the second silicon detector which samples a broad optical bandwidth and has a fast response time. Results from experiments on the undercooling and solidification behavior of electromagnetically levitated pure nickel show that the solidification velocity approaches 17 m/s at high undercooling.

  1. Intake condition requirements for biodiesel modulated kinetic combustion concept to achieve a simultaneous NOx and soot removal

    International Nuclear Information System (INIS)

    Kim, Keunsoo; Oh, Seungmook; Lee, Yonggyu; Lee, Sunyoup; Kim, Junghwan

    2015-01-01

    Highlights: • MK LTC combustion was investigated under various intake conditions. • BD20 MK combustion achieved NO x and soot removal at achievable intake conditions. • The BD20 best point showed lower ISFC and COV IMEP than the diesel best point. • Higher intake pressure showed higher efficiency at all intake oxygen concentrations. • Simultaneous NO x and soot removal required 200 kPa intake pressure at a medium load. - Abstract: The fuel oxygen contained in oxygenated fuels can help reduce harmful engine-out emissions and improve the combustion process in compression-ignition engines. The use of soybean methylene ether biodiesel in the low-temperature combustion (LTC) regime has the potential to suppress soot formation and nitrogen oxides (NO x ) emissions even further, which eventually alleviates the burden of the after-treatment system. In the present study, the effects of the intake pressure and injection timing on the combustion and emissions of the modulated kinetic (MK) combustion concept with ultra-low sulfur diesel and 20% biodiesel blended fuel (BD20) were investigated in a single-cylinder CI engine. The intake pressure was varied from 100 kPa to 250 kPa for the intake oxygen concentration range of 11–17%. The engine test results indicate that simultaneous reductions in both the NO x and soot emissions were realized under the MK LTC combustion regime. At the best operating point, BD20 achieved the simultaneous NO x and soot removal at a lower intake pressure and lower EGR level than diesel, which led to better fuel economy. In addition, BD20 achieved acceptable levels of combustion stability and noise level

  2. Soot Superaggregates from Flaming Wildfires and Their Direct Radiative Forcing

    Science.gov (United States)

    Chakrabarty, Rajan K.; Beres, Nicholas D.; Moosmuller,Hans; China, Swarup; Mazzoleni, Claudio; Dubey, Manvendra K.; Liu, Li; Mishchenko, Michael I.

    2014-01-01

    Wildfires contribute significantly to global soot emissions, yet their aerosol formation mechanisms and resulting particle properties are poorly understood and parameterized in climate models. The conventional view holds that soot is formed via the cluster-dilute aggregation mechanism in wildfires and emitted as aggregates with fractal dimension D(sub f) approximately equals 1.8 mobility diameter D(sub m) (is) less than or equal to 1 micron, and aerodynamic diameter D(sub a) (is) less than or equal to 300 nm. Here we report the ubiquitous presence of soot superaggregates (SAs) in the outflow from a major wildfire in India. SAs are porous, low-density aggregates of cluster-dilute aggregates with characteristic D(sub f) approximately equals 2.6,D(sub m) (is) greater than 1 micron, and D(sub a) is less than or equal to 300 nm that form via the cluster-dense aggregation mechanism.We present additional observations of soot SAs in wildfire smoke-laden air masses over Northern California, New Mexico, and Mexico City. We estimate that SAs contribute, per unit optical depth, up to 35% less atmospheric warming than freshly-emitted (D(sub f) approximately equals 1.8) aggregates, and approximately equals 90% more warming than the volume-equivalent spherical soot particles simulated in climate models.

  3. Research of temperature field measurement using a flexible temperature sensor array for robot sensing skin

    Science.gov (United States)

    Huang, Ying; Wu, Siyu; Li, Ruiqi; Yang, Qinghua; Zhang, Yugang; Liu, Caixia

    2013-10-01

    This paper presents a novel temperature sensor array by dispensing conductive composites on a flexible printed circuit board which is able to acquire the ambient temperature. The flexible temperature sensor array was fabricated by using carbon fiber-filled silicon rubber based composites on a flexible polyimide circuit board, which can both ensure their high flexibility. It found that CF with 12 wt% could be served as the best conductive filler for higher temperature sensitivity and better stability comparing with some other proportion for dynamic range from 30&° to 90°. The preparation of the temperature sensitive material has also been described in detail. Connecting the flexible sensor array with a data acquisition card and a personal computer (PC), some heat sources with different shapes were loaded on the sensor array; the detected results were shown in the interface by LabVIEW software. The measured temperature contours are in good agreement with the shapes and amplitudes of different heat sources. Furthermore, in consideration of the heat dissipation in the air, the relationship between the resistance and the distance of heat sources with sensor array was also detected to verify the accuracy of the sensor array, which is also a preparation for our future work. Experimental results demonstrate the effectiveness and accuracy of the developed flexible sensor array, and it can be used as humanoid artificial skin for sensation system of robots.

  4. High resolution temperature measurements in the borehole Yaxcopoil-1, Mexico

    Czech Academy of Sciences Publication Activity Database

    Wilhelm, H.; Heidinger, P.; Šafanda, Jan; Čermák, Vladimír; Burkhardt, H.; Popov, Y.

    2004-01-01

    Roč. 39, č. 6 (2004), s. 813-819 ISSN 1086-9379 R&D Projects: GA ČR GA205/03/0997; GA AV ČR KSK3012103 Grant - others:Deutsche Forschungsgemeinschaft(DE) WI687/17-1 Institutional research plan: CEZ:AV0Z3012916 Keywords : temperature measurements * borehole * Mexico Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.673, year: 2004

  5. Gas temperature measurements in short duration turbomachinery test facilities

    Science.gov (United States)

    Cattafesta, L. N.; Epstein, A. H.

    1988-07-01

    Thermocouple rakes for use in short-duration turbomachinery test facilities have been developed using very fine thermocouples. Geometry variations were parametrically tested and showed that bare quartz junction supports (76 microns in diameter) yielded superior performance, and were rugged enough to survive considerable impact damage. Using very low cost signal conditioning electronics, temperature accuracies of 0.3 percent were realized yielding turbine efficiency measurements at the 1-percent level. Ongoing work to improve this accuracy is described.

  6. Estimating Wet Bulb Globe Temperature Using Standard Meteorological Measurements

    International Nuclear Information System (INIS)

    Hunter, C.H.

    1999-01-01

    The heat stress management program at the Department of Energy''s Savannah River Site (SRS) requires implementation of protective controls on outdoor work based on observed values of wet bulb globe temperature (WBGT). To ensure continued compliance with heat stress program requirements, a computer algorithm was developed which calculates an estimate of WBGT using standard meteorological measurements. In addition, scripts were developed to generate a calculation every 15 minutes and post the results to an Intranet web site

  7. PCPV instrumentation and measurement techniques at elevated temperatures

    International Nuclear Information System (INIS)

    Zemann, H.

    1978-11-01

    Strain measurement within the structural concrete of the prototype Prestressed Concrete Pressure Vessel have been performed during a one year operation at elevated temperatures up to 120 0 C. Laboratory investigations on the properties of the gauges and the concrete mix are applied to separate the different contributions to the strain data. A decrease of creep and loss of prestress and the arise of stable conditions is observed. (author)

  8. Sulfuric Acid and Soot Particle Formation in Aircraft Exhaust

    Science.gov (United States)

    Pueschel, Rudolf F.; Verma, S.; Ferry, G. V.; Howard, S. D.; Vay, S.; Kinne, S. A.; Baumgardner, D.; Dermott, P.; Kreidenweis, S.; Goodman, J.; hide

    1997-01-01

    A combination of CN counts, Ames wire impactor size analyses and optical particle counter data in aircraft exhaust results in a continuous particle size distribution between 0.01 micrometer and 1 micrometer particle radius sampled in the exhaust of a Boeing 757 research aircraft. The two orders of magnitude size range covered by the measurements correspond to 6-7 orders of magnitude particle concentration. CN counts and small particle wire impactor data determine a nucleation mode, composed of aircraft-emitted sulfuric acid aerosol, that contributes between 62% and 85% to the total aerosol surface area and between 31% and 34% to its volume. Soot aerosol comprises 0.5% of the surface area of the sulfuric acid aerosol. Emission indices are: EIH2SO4 = 0.05 g/kgFUEL and (0.2-0.5) g/kgFUEL (for 75 ppmm and 675 ppmm fuel-S, respectively), 2.5E4sulfur (gas) to H2SO4 (particle) conversion efficiency is between 10% and 25%.

  9. High-temperature rate constant measurements for OH+xylenes

    KAUST Repository

    Elwardani, Ahmed Elsaid

    2015-06-01

    The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k 1), m-xylene (k 2), and p-xylene (k 3) were measured behind reflected shock waves over 890-1406K at pressures of 1.3-1.8atm using OH laser absorption near 306.7nm. Measurements were performed under pseudo-first-order conditions. The measured rate constants, inferred using a mechanism-fitting approach, can be expressed in Arrhenius form as:k1=2.93×1013exp(-1350.3/T)cm3mol-1s-1(890-1406K)k2=3.49×1013exp(-1449.3/T)cm3mol-1s-1(906-1391K)k3=3.5×1013exp(-1407.5/T)cm3mol-1s-1(908-1383K)This paper presents, to our knowledge, first high-temperature measurements of the rate constants of the reactions of xylene isomers with OH radicals. Low-temperature rate-constant measurements by Nicovich et al. (1981) were combined with the measurements in this study to obtain the following Arrhenius expressions, which are applicable over a wider temperature range:k1=2.64×1013exp(-1181.5/T)cm3mol-1s-1(508-1406K)k2=3.05×109exp(-400/T)cm3mol-1s-1(508-1391K)k3=3.0×109exp(-440/T)cm3mol-1s-1(526-1383K) © 2015 The Combustion Institute.

  10. MTF measurement of IR optics in different temperature ranges

    Science.gov (United States)

    Bai, Alexander; Duncker, Hannes; Dumitrescu, Eugen

    2017-10-01

    Infrared (IR) optical systems are at the core of many military, civilian and manufacturing applications and perform mission critical functions. To reliably fulfill the demanding requirements imposed on today's high performance IR optics, highly accurate, reproducible and fast lens testing is of crucial importance. Testing the optical performance within different temperature ranges becomes key in many military applications. Due to highly complex IR-Applications in the fields of aerospace, military and automotive industries, MTF Measurement under realistic environmental conditions become more and more relevant. A Modulation Transfer Function (MTF) test bench with an integrated thermal chamber allows measuring several sample sizes in a temperature range from -40 °C to +120°C. To reach reliable measurement results under these difficult conditions, a specially developed temperature stable design including an insulating vacuum are used. The main function of this instrument is the measurement of the MTF both on- and off-axis at up to +/-70° field angle, as well as measurement of effective focal length, flange focal length and distortion. The vertical configuration of the system guarantees a small overall footprint. By integrating a high-resolution IR camera with focal plane array (FPA) in the detection unit, time consuming measurement procedures such as scanning slit with liquid nitrogen cooled detectors can be avoided. The specified absolute accuracy of +/- 3% MTF is validated using internationally traceable reference optics. Together with a complete and intuitive software solution, this makes the instrument a turn-key device for today's state-of- the-art optical testing.

  11. Active silicon x-ray for measuring electron temperature

    International Nuclear Information System (INIS)

    Snider, R.T.

    1994-07-01

    Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

  12. Actual evaporation estimation from infrared measurement of soil surface temperature

    Directory of Open Access Journals (Sweden)

    Davide Pognant

    2013-09-01

    Full Text Available Within the hydrological cycle, actual evaporation represents the second most important process in terms of volumes of water transported, second only to the precipitation phenomena. Several methods for the estimation of the Ea were proposed by researchers in scientific literature, but the estimation of the Ea from potential evapotranspiration often requires the knowledge of hard-to-find parameters (e.g.: vegetation morphology, vegetation cover, interception of rainfall by the canopy, evaporation from the canopy surface and uptake of water by plant roots and many existing database are characterized by missing or incomplete information that leads to a rough estimation of the actual evaporation amount. Starting from the above considerations, the aim of this study is to develop and validate a method for the estimation of the Ea based on two steps: i the potential evaporation estimation by using the meteorological data (i.e. Penman-Monteith; ii application of a correction factor based on the infrared soil surface temperature measurements. The dataset used in this study were collected during two measurement campaigns conducted both in a plain testing site (Grugliasco, Italy, and in a mountain South-East facing slope (Cogne, Italy. During those periods, hourly measurement of air temperature, wind speed, infrared surface temperature, soil heat flux, and soil water content were collected. Results from the dataset collected in the two testing sites show a good agreement between the proposed method and reference methods used for the Ea estimation.

  13. Measuring the temperature history of isochorically heated warm dense metals

    Science.gov (United States)

    McGuffey, Chris; Kim, J.; Park, J.; Moody, J.; Emig, J.; Heeter, B.; Dozieres, M.; Beg, Fn; McLean, Hs

    2017-10-01

    A pump-probe platform has been designed for soft X-ray absorption spectroscopy near edge structure measurements in isochorically heated Al or Cu samples with temperature of 10s to 100s of eV. The method is compatible with dual picosecond-class laser systems and may be used to measure the temperature of the sample heated directly by the pump laser or by a laser-driven proton beam Knowledge of the temperature history of warm dense samples will aid equation of state measurements. First, various low- to mid-Z targets were evaluated for their suitability as continuum X-ray backlighters over the range 200-1800 eV using a 10 J picosecond-class laser with relativistic peak intensity Alloys were found to be more suitable than single-element backlighters. Second, the heated sample package was designed with consideration of target thickness and tamp layers using atomic physics codes. The results of the first demonstration attempts will be presented. This work was supported by the U.S. DOE under Contract No. DE-SC0014600.

  14. Hysteresis and Temperature Dependency of Moisture Sorption – New Measurements

    DEFF Research Database (Denmark)

    Rode, Carsten; Hansen, Kurt Kielsgaard

    2011-01-01

    for combined heat and moisture transport in materials. There is a need for further elaboration of the importance of these issues, and it is the intent of this paper to contribute to such elaboration. The paper seeks to contribute to the knowledge base about such sorption characteristic by presenting some new...... measurements of hysteresis and temperature dependency of the moisture sorption characteristics of three different porous building materials: aerated concrete, cement paste and spruce. Scanning curves are measured for all three materials where periods with adsorption and desorption interrupt each other...

  15. Laser metrology in fluid mechanics granulometry, temperature and concentration measurements

    CERN Document Server

    Boutier, Alain

    2013-01-01

    In fluid mechanics, non-intrusive measurements are fundamental in order to improve knowledge of the behavior and main physical phenomena of flows in order to further validate codes.The principles and characteristics of the different techniques available in laser metrology are described in detail in this book.Velocity, temperature and concentration measurements by spectroscopic techniques based on light scattered by molecules are achieved by different techniques: laser-induced fluorescence, coherent anti-Stokes Raman scattering using lasers and parametric sources, and absorption sp

  16. Measurement of ocean temperature and salinity via microwave radiometry

    Science.gov (United States)

    Blume, H.-J. C.; Kendall, B. M.; Fedors, J. C.

    1978-01-01

    Sea-surface temperature with an accuracy of 1 C and salinity with an accuracy of 1% were measured with a 1.43 and 2.65 GHz radiometer system after correcting for the influence of cosmic radiation, intervening atmosphere, sea-surface roughness, and antenna beamwidth. The radiometers are a third-generation system using null-balancing and feedback noise injection. Flight measurements from aircraft over bay regions and coastal areas of the Atlantic resulted in co