| 1. |
- Bladh, Henrik, et al.
(författare)
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Probing the smallest soot particles in low-sooting premixed flames using laser-induced incandescence
- 2015
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 35, s. 1843-1850
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Tidskriftsartikel (refereegranskat)abstract
- In this work we investigate nascent soot particles by analyzing laser-induced incandescence (LII) signals obtained in low-sooting premixed flames. The analysis covers two data sets obtained in separate experimental campaigns. The first data set was obtained in a previous work (Mouton et al., 2013) in methane/oxygen/nitrogen flames (equivalence ratio range 1.95 < Phi < 2.32) at 26.7 kPa, whereas the second was performed in atmospheric ethylene/air flames (1.77 < Phi < 2.00). Both studies show similar trends, i.e. a gradual change of the fluence curves (evolution of the LII signal as function of the laser fluence) from the well-known S-shaped curve for mature soot found at high heights above the burner (HAB) and high equivalence ratio, to a nearly linear behavior for nascent soot found at low HAB and reduced equivalence ratio. With this change comes a decrease in the LII decay time (and hence inferred particle size). Also, this decay time appears to be almost constant with HAB in flames having the lowest equivalence ratio at which the incandescence signal could be detected. In these flames, so-called nucleation flames, the stability of the particle size with HAB suggests that recently nucleated particles have undergone marginal surface growth and coagulation. Existence of such nucleation flames is of great interest for improving the theoretical description of the nucleation step. Experimental results are analyzed by using a theoretical model for LII to determine the particle size evolution throughout the flame at various experimental conditions. We highlight the size difference from nascent soot particles up to mature soot, giving insight into the particle nucleation and the surface growth processes as a function of reaction time and flame conditions. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 2. |
- Gallo, Yann, et al.
(författare)
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Investigation of Late-Cycle Soot Oxidation Using Laser Extinction and In-Cylinder Gas Sampling at Varying Inlet Oxygen Concentrations in Diesel Engines
- 2017
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Ingår i: Fuel. - : Elsevier BV. - 1873-7153 .- 0016-2361. ; 193, s. 308-314
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the relative importance of O2 and OH as oxidizers of soot during the late cycle in diesel engines, where the soot oxidation is characterized in an optically accessible engine using laser extinction measurements. These are combined with in cylinder gas sampling data from a single cylinder engine fitted with a fast gas sampling valve. Both measurements confirm that the in-cylinder soot oxidation slows down when the inlet concentration of O2 is reduced. A 38% decrease in intake O2 concentration reduces the soot oxidation rate by 83%, a non-linearity suggesting that O2 in itself is not the main soot oxidizing species. Chemical kinetics simulations of OH concentrations in the oxidation zone and estimates of the OH soot oxidation rates point towards OH being the dominant oxidizer.
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| 3. |
- Lind, Ted, et al.
(författare)
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Simultaneous PLIF Imaging of OH and PLII Imaging of Soot for Studying the Late-Cycle Soot Oxidation in an Optical Heavy-Duty Diesel Engine
- 2016
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Ingår i: SAE International Journal of Engines. - : SAE International. - 1946-3936 .- 1946-3944. ; 9:2, s. 849-858
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Tidskriftsartikel (refereegranskat)abstract
- The effects of injection pressure and swirl ratio on the in-cylinder soot oxidation are studied using simultaneous PLIF imaging of OH and LII imaging of soot in an optical diesel engine. Images are acquired after the end of injection in the recirculation zone between two adjacent diesel jets. Scalars are extracted from the images and compared with trends in engine-out soot emissions. The soot emissions decrease monotonically with increasing injection pressure but show a non-linear dependence on swirl ratio. The total amount of OH in the images is negatively correlated with the soot emissions, as is the spatial proximity between the OH and soot regions. This indicates that OH is an important soot oxidizer and that it needs to be located close to the soot to perform this function. The total amount of soot in the images shows no apparent correlation with the soot emissions, indicating that the amount of soot formed is a poor predictor of the emission trends.
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| 4. |
- Nordström, Emil, et al.
(författare)
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Local gas heating in sooting flames by heat transfer from laser-heated particles investigated using rotational CARS and LII
- 2015
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 35, s. 3707-3713
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Tidskriftsartikel (refereegranskat)abstract
- Soot particles strongly absorb radiation in the visible and infrared spectral regions, and the soot interaction with laser light during laser diagnostic interrogation leads to particle heating and often to subsequent sublimation. Consequently, laser-heated particles transfer heat to the ambient gas leading to local gas heating, a process that has received minor attention so far in the diagnostic community. In the present work, this specific local gas heating is measured in a pump-probe-type experiment. A 1064-nm laser beam heated the soot particles in an ethylene/ air diffusion flame (on a Gulder-burner) with known soot volume fraction, and a two-beam rotational coherent anti-Stokes Raman spectroscopy (CARS) setup was used to probe the local gas temperature on time scales from nanoseconds to milliseconds. The temperature of the heated particles was simultaneously probed using a two-color laser-induced incandescence (2C-LII) detection system. The results show that laser heating of soot particles from flame temperatures to sublimation temperatures leads to local gas heating of similar to 100 K at a soot volume fraction of 4 ppm, in good agreement with theoretical predictions. The implication of these results to the application of laser diagnostic techniques is briefly discussed. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 5. |
- Olofsson, Nils-Erik, et al.
(författare)
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Evolution of properties for aging soot in premixed flat flames studied by laser-induced incandescence and elastic light scattering
- 2015
-
Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 119:4, s. 669-683
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Tidskriftsartikel (refereegranskat)abstract
- A detailed study has been made of soot growth in two premixed flat ethylene/air flames, at I broken vertical bar = 2.1 and I broken vertical bar = 2.3, where focus has been on following the change in optical properties from nascent to more mature soot, and the importance of these properties for laser-induced incandescence (LII). A combination of two-color LII (2C-LII) and elastic light scattering was utilized for studies of soot absorption and sublimation for a range of laser fluences in a pump-probe experiment, and the experimental results were compared with LII model predictions. Both flames show similar trends, indicating that the soot becomes less transparent during the growth process until some level of maturity is reached at higher flame heights, where the measured properties reach almost constant values. A sublimation fluence threshold of similar to 0.14 J/cm(2) (at 1064 nm for a flame temperature around 1700 K) was evaluated for mature soot, corresponding to a sublimation temperature of similar to 3400 K. Soot peak temperatures from 2C-LII were evaluated both using a constant E(m) and a wavelength dependence for E(m) extracted from extinction measurements, leading to a discussion on how the sublimation temperature relates to the maturity of soot.
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| 6. |
- Robert, Etienne, et al.
(författare)
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Soot Formation in Unstrained Diffusion Flames
- 2015
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Ingår i: Combustion Science and Technology. - : Informa UK Limited. - 1563-521X .- 0010-2202. ; 187:4, s. 577-593
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Tidskriftsartikel (refereegranskat)abstract
- The formation of soot particles has been investigated in CH4/O-2 diffusion flames using a unique burner design, which allows the creation of a nearly unstrained planar reaction sheet. Spatially resolved soot volume fractions were obtained using laser-induced incandescence. These soot measurements and the sooting limits were obtained as a function of bulk flow across the flame and mixture strength. Samples were collected using thermophoretic sampling and analyzed using electron microscopy, revealing a broad range of microstructures including particles with unusually large primary diameters and carbon nanotubes. A theoretical model is presented, which confirms that under certain conditions the 1D nature of the flow field of the burner and the strong adverse temperature gradient on the fuel side of the flame result in the soot particles being held in place by thermophoretic forces and allowed to grow for very long time periods. Some of these so-called super aggregates reached sizes of tens of microns and became visible to the naked eye in the soot layer.
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| 7. |
- Simonsson, Johan, et al.
(författare)
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Influence of potassium and iron chloride on the early stages of soot formation studied using imaging LII/ELS and TEM techniques
- 2017
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 36:1, s. 853-860
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced incandescence (LII), elastic light scattering (ELS) and extinction were used to investigate the early stages of soot formation when seeding metal salts at various concentrations into a premixed ethylene/air flame on a PerkinElmer burner. The investigation contained seven salts, where we in this work mainly focus on two of these salts, potassium chloride (KCl) and iron chloride (FeCl3), as these for mature soot resulted in the largest reduction and highest increase in soot concentration, respectively. The optical measurements show that the potassium chloride significantly reduces the build-up of larger soot precursors and also decreases the sizes of the primary soot particles both at the nucleation stage as well as for more mature soot later in the formation process. This is also confirmed by analysis of transmission electron microscopy (TEM) images, which clearly show smaller primary soot particles for the potassium chloride-seeded flame. The iron chloride-seeded flames were found to have marginal influence on the primary particle sizes based on the optical data, although somewhat more irregular shapes could be observed in TEM images.
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| 8. |
- Simonsson, Johan, et al.
(författare)
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Influence of potassium chloride and other metal salts on soot formation studied using imaging LII and ELS, and TEM techniques
- 2018
-
Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 190, s. 188-200
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Tidskriftsartikel (refereegranskat)abstract
- An experimental investigation has been performed where the influence of metal salts on soot formation has been studied. By combining two-dimensional laser-induced incandescence (LII) and elastic light scattering (ELS), two-dimensional information could be obtained on soot properties in the flames. For these studies, seven metal salts (NaCl, MgCl2, AlCl3, KCl, CaCl2, FeCl3 and ZnCl2) were dissolved in water and aspirated into a premixed ethylene/air flame. At lower flame heights, in the soot inception region, the LII signal (representing soot volume fraction) was marginally affected by all additives, whereas the ELS signal strongly decreased with increasing additive concentration for the alkali salts. At higher heights, in the soot growth region, the soot volume fractions were lowered for the addition of potassium, calcium and sodium chloride, in order of significance. Some of the salts (MgCl2, AlCl3 and FeCl3) resulted in negligible influence on LII signals and slightly higher ELS signals throughout the flames, and we relate the increased ELS signals to salt particles propagating through the flame. Main focus in our study was on the addition of potassium chloride for which several parameters were investigated. For example, soot primary particle sizes were evaluated using combined LII and ELS, showing decreasing particle sizes for increasing concentrations of potassium, in reasonable agreement with particle sizes evaluated using transmission electron microscopy. Also, CARS thermometry showed slightly higher flame temperature, ∼30 K, for the potassium-seeded flame compared to the reference flame.
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| 9. |
- Simonsson, Johan, et al.
(författare)
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Wavelength dependence of extinction in sooting flat premixed flames in the visible and near-infrared regimes
- 2015
-
Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 119:4, s. 657-667
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Tidskriftsartikel (refereegranskat)abstract
- A diode-laser-based setup was used for extinction measurements at various heights in two flat premixed sooting ethylene/air flames in order to investigate the wavelength dependence of the extinction. Twelve laser wavelengths were used in the interval 405-1064 nm, and with this setup, a sensitivity of similar to 10(-4) was achieved for the extinction. Soot volume fractions inferred from the extinction measurements were always higher in the visible spectral region than in the infrared, an effect associated with additional absorption by large hydrocarbons, such as polycyclic aromatic hydrocarbons. For wavelengths greater than around 700 nm and at high heights above burner (HAB), the extinction shows an inverse dependence with wavelength, in concurrence with wavelength-independent optical properties of soot. In the same spectral region at lower HAB, the wavelength dependence is observed to be stronger, indicating that the soot optical properties show variation with wavelength. Furthermore, a continuous change in the wavelength dependence of the absorption function E(m) is shown from nascent soot at lower heights to more mature soot at higher heights. The presented results are of importance for soot diagnostics relying on the efficiency of light absorption by soot such as laser-induced incandescence (LII).
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Borggren, Jesper, et al.
(författare)
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Diode laser-based thermometry using two-line atomic fluorescence of indium and gallium
- 2017
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Ingår i: Applied Physics B: Lasers and Optics. - : Springer Science and Business Media LLC. - 0946-2171. ; 123:12
-
Tidskriftsartikel (refereegranskat)abstract
- A robust and relatively compact calibration-free thermometric technique using diode lasers two-line atomic fluorescence (TLAF) for reactive flows at atmospheric pressures is investigated. TLAF temperature measurements were conducted using indium and, for the first time, gallium atoms as temperature markers. The temperature was measured in a multi-jet burner running methane/air flames providing variable temperatures ranging from 1600 to 2000 K. Indium and gallium were found to provide a similar accuracy of ~ 2.7% and precision of ~ 1% over the measured temperature range. The reliability of the TLAF thermometry was further tested by performing simultaneous rotational CARS measurements in the same experiments.
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| 14. |
- Brackmann, Christian, et al.
(författare)
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Experimental studies of nitromethane flames and evaluation of kinetic mechanisms
- 2018
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 190, s. 327-336
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Tidskriftsartikel (refereegranskat)abstract
- The present work reports new experimental data for premixed flames of nitromethane, CH3NO2, at atmospheric pressure, and an evaluation of two contemporary kinetic mechanisms based on these new flame studies as well as previously published experimental data on laminar burning velocity and ignition. Flames of nitromethane + air at lean (ϕ = 0.8) and rich (ϕ = 1.2) conditions were stabilized on a flat-flame burner, where profiles of CH2O, CO and NO were obtained using laser-induced fluorescence and temperature profiles using coherent anti-Stokes Raman spectroscopy. Laminar burning velocities for nitromethane + O2 + CO2 were measured using the heat flux method for ϕ = 0.8–1.3 at 348 K and ϕ = 0.8–1.6 at 358 K, and an oxidizer composition of 35% O2 and 65% CO2. In addition, the effect of the oxidizer composition was examined for a stoichiometric flame at 358 K by varying oxygen fraction from 30% to 40%. The mechanism by Mathieu et al. (Fuel 2016, 182, 597), previously not validated for flames, was able to reproduce experimental laminar burning velocities for nitromethane + air, but under predicted new results for CH3NO2 + O2 + CO2 mixtures. The mechanism by Brequigny et al. (Proc. Combust. Inst. 2014, 35, 703) under predicted experimental laminar burning velocities significantly at all investigated conditions. Previous studies have shown that none of the mechanisms can accurately predict ignition delay time over a wide range of conditions with respect to pressure, temperature, diluent and dilution ratio. The evaluation of the mechanisms reveals that the understanding of nitromethane combustion is at the present time not sufficient to produce a widely applicable mechanism.
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| 15. |
- Brackmann, Christian, et al.
(författare)
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Structure of premixed ammonia plus air flames at atmospheric pressure: Laser diagnostics and kinetic modeling
- 2016
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 163, s. 370-381
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Tidskriftsartikel (refereegranskat)abstract
- The structure of premixed ammonia air flames, burning at atmospheric pressure under strain-stabilized conditions on a porous-plug burner, has been investigated using laser-diagnostic methods. Profiles of OH, NH, and NO were acquired by laser-induced fluorescence (LIF) and quantitative concentrations of OH and NO were retrieved using a concept for calibration versus absorption utilizing the LIF-signal itself, whereas NH concentrations were evaluated employing a saturated fluorescence signal. In addition, temperatures and relative oxygen concentrations were measured by rotational Coherent Anti-stokes Raman Spectroscopy (CARS). The new experimental data for flames with equivalence ratios of 0.9, 1.0, and 1.2 were used to validate and rank the performance of four contemporary detailed kinetic models. Simulations were carried out using experimental temperature profiles as well as by solving the energy equation. Two models of the same origin, developed by Mendiara and Glarborg (2009) and by Klippenstein et al. (2011), in most cases showed good agreement in terms of radical concentrations, however, the model of Mendiara and Glarborg had better prediction of temperatures and flame front positions. The model by Shmakov et al. (2010) had comparable performance concerning radical species, but significant discrepancies appeared in the prediction of flame front positions. The model of Duynslaegher et al. (2012), in addition to the flame front positions, deviated from experiments or other models in terms of NH and NO concentrations. A sensitivity analysis for the Mendiara-Glarborg mechanism indicated that remaining uncertainties of the rate constants implemented in the recent H/N/O models are difficult to scrutinize unambiguously due to experimental uncertainties. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 16. |
- Carlsson, Henning, et al.
(författare)
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Numerical and experimental study of flame propagation and quenching of lean premixed turbulent low swirl flames at different Reynolds numbers
- 2015
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 162:6, s. 2582-2591
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a joint experimental and large eddy simulation (LES) study of lean premixed low swirl stabilized methane/air flames at different Reynolds numbers (Re similar to 20,000-100,000). The aims are to investigate the sensitivity of the structures and dynamics of low swirl flames to the inflow boundary conditions and to evaluate the capability of an LES flamelet model in predicting the stabilization and local extinction of the flames. Chemiluminescence measurements are carried out for Re - 20,000-50,000 and further detailed oxygen concentration and temperature fields are measured using rotational coherent anti-Stokes Raman spectroscopy (RCARS) for Re - 20,000 and 30,000 along the centerline of the burner and at various radial positions at different heights above the burner. The data are used first for validation of the combustion LES model employed in the numerical simulations, and then the RCARS and LES results are used to delineate the effect of ambient air entrainment on the flame structure at various burner exit velocities. A three-scalar flamelet model based on a level-set G-equation shows excellent predictions of the lift-off positions and the structures of the flames, including quenching at the trailing edge of the flame. The results show that the flame lift-off height varies only slightly when the burner exit velocity is increased, which is consistent with a shear-layer flame stabilization mechanism reported previously. The volume of the flame decreases substantially with increasing burner exit velocity at relatively low Reynolds numbers, as a result of flame quenching at the trailing edge of the flame caused by entrainment of the ambient air into the fuel/air stream and the flame itself. At high Reynolds numbers the flame structures become fairly self-similar with the flame volume nearly independent of the Reynolds number. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 17. |
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| 18. |
- Gallo, Yann, et al.
(författare)
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A Study of In-Cylinder Soot Oxidation by Laser Extinction Measurements During an EGR-Sweep in an Optical Diesel Engine
- 2015
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
-
Tidskriftsartikel (refereegranskat)abstract
- Two competing in-cylinder processes, soot formation and soot oxidation, govern soot emissions from diesel engines. Previous studies have shown a lack of correlation between the soot formation rate and soot emissions. The current experiment focuses on the correlation between soot oxidation rates and soot emissions. Laser extinction is measured using a red (690nm) laser beam, which is sent vertically through the cylinder. This wavelength is long enough to minimize absorption interference from poly-aromatic hydrocarbons, while still in the visible regime. It is modulated at 72 kHz in order to produce 10 pulses per crank angle degree at an engine speed of 1200 rpm. The intake oxygen concentration is varied between 9% and 21%. The time resolved extinction measurements are used to estimate soot oxidation rates during expansion. High-speed video imaging is used in conjunction with the laser-extinction technique to indicate the location of the sooting regions, and to assess beam steering effects. The oxidation processes are described using single exponential decay fits and an attempt to correlate them with the late cycle rate of heat release was made.
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| 19. |
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| 20. |
- Gunnarsson, Adrian, 1990, et al.
(författare)
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Radiative Heat Transfer Modeling and in Situ Diagnostics of Soot in an 80 kWth Propane Flame with Varying Feed-Gas Oxygen Concentration
- 2018
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 57:36, s. 12288-12295
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Tidskriftsartikel (refereegranskat)abstract
- This work presents experimental measurements of various 80 kWth propane flames, using a swirl burner, and modeling of the radiative heat transfer. The combustion conditions were altered by varying the oxygen concentration in the oxidant within range of 21-32%, while keeping the thermal input and oxygen-to-fuel ratio constant. Temperature, gas composition, and radiative intensity were measured using probes, while the soot volume fraction was quantified using nonintrusive laser-induced incandescence. The radiative intensity and the soot volume fraction increased with an increased oxygen concentration in the flame. When the oxygen concentration exceeded 27% the soot volume fraction was increased more than 14-fold. The results reveal the potential of promoting radiative heat transfer by increasing the oxygen concentration; the total radiative intensity becomes dominated by the soot particle contribution. In addition, laser-induced incandescence was successfully used for instantaneous and spatially resolved soot measurements in this type of furnace being at a technical scale.
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| 21. |
- Gunnarsson, Adrian, 1990, et al.
(författare)
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Soot Formation and Radiative Heat Transfer in Oxy-Fuel and Oxygen-Enhanced Propane Flames
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This work aims to determine radiation-related properties of various propane flames, where the measurements were conducted in a down-fired and cylindrical 100 kW furnace equipped with a swirl burner. The combustion conditions were varied by altering the composition of the oxidant. For six cases, oxygen-enhanced air was used, step-wise varying the oxygen concentration in the oxidant from 21% to 32%. Also for six cases, the furnace was operated in oxy-fuel mode, recirculating dry flue gas and varying the oxygen concentration from 25% to 42%. All measurements were conducted at an axial distance of 384 mm from the burner. Temperature, gas composition and radiative intensity were measured (by intrusive instruments) along the furnace diameter using probes while the soot volume fraction was quantified using non-intrusive laser induced incandescence (LII). An Nd:YAG laser at wavelength 1064 nm was used for the LII measurements, and a diode laser at wavelength 808 nm was used for extinction measurements for absolute calibration of the LII-signal. Two-dimensional images of the LII-signal were captured using an intensified CCD-camera and radial profiles of the soot volume fraction were achieved. The soot volume fraction increased with increasing oxygen concentration in the feed gas, and, when the oxygen concentration exceeded 30 and 42% for the oxygen-enriched air and oxy-fuel cases, respectively, the soot formation was substantially enhanced with volume fractions more than 10 times higher than for lower oxygen concentrations. The higher oxygen concentration required for the increased soot production in the oxy-fuel combustion cases is mainly due to the higher heat capacity of carbon dioxide that lowers the flame temperatures. The data collected from the measurements was used to model the radiative intensity using a discrete transfer model. In this model, gas properties are calculated using a statistical narrow-band model and particle properties are calculated using Rayleigh theory. Good agreement was achieved between the modeled and measured radiative intensity for most flames and the use of an LII-system to measure the soot volume fraction in this type of furnace was successful.
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| 22. |
- Hedborg Bengtsson, Susanna, et al.
(författare)
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The influence of construction project actors' motivation on externally initiated systemic innovation
- 2017
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Ingår i: PROCEEDINGS OF THE 9TH NORDIC CONFERENCE ON CONSTRUCTION ECONOMICS AND ORGANIZATION. - Lyngby : POLYTEKNISK FORLAG. - 9788750211259 ; , s. 208-219
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Konferensbidrag (refereegranskat)abstract
- Urbanization and climate change are central challenges for urban development today, why a need for substantial innovation, e.g. systemic innovation, can be identified. The large amount of interdependent actors and their fragmented processes are among the key factors that hamper innovation in the construction industry. Two key actors in the industry, property developers and contractors, can be identified as important when developing innovation, due to their central roles in the construction project process. Therefore, it should be important to make them dedicated towards innovation, i.e. create motivation. This is in line with research on successful innovation development highlighting the importance of commitment and collaboration. A need seems to be present to create motivation towards innovation for key actors in the industry. Based on this, the purpose of this paper is to explore how motivation of key actors can influence development for systemic innovation in the construction industry. To explore this, a case study of the urban development project Stockholm Royal Seaport and its developed building logistic center was analyzed, adopting a model for receptive change context. Tentative findings suggest that actors' motivation for innovation is important for the development. Developers' possibility to influence through procurement strategies, to increase awareness and collaboration, can be used to create motivation for contractors.
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| 23. |
- Hedborg Bengtsson, Susanna, et al.
(författare)
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Users’ influence on inter-organizational innovation : mapping the receptive context
- 2018
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Ingår i: Construction Innovation. - : Emerald Group Publishing Limited. - 1471-4175 .- 1477-0857. ; 18:4, s. 488-504
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Tidskriftsartikel (refereegranskat)abstract
- PurposeInnovation is constantly present in the construction industry, however, mainly on a single project level. Initiating and implementing inter-organizational innovation in a multi-project context such as in urban development entails large complexity, for example, because of the many interdependent projects and users of innovation. The users’ influence on inter-organizational innovation in a multi-project context has not been fully explored. Accordingly, the purpose of this paper is to discuss how users influence inter-organizational innovation in multi-project contexts by mapping the receptiveness for change.Design/methodology/approachA single case study approach was used, where empirical material including semi-structured interviews in combination with meeting observations, document studies and participative workshops were gathered. The rich empirical material, studying inter-organizational innovation in an urban development context, was mapped based on the receptive context for change framework.FindingsA receptive context for change was not present in the studied multi-project context. Communication to develop and implement inter-organizational innovation was not sufficient and the clients’ procurement strategies were to a large extent not developed to facilitate inter-organizational innovation. Findings show differences in users’ possibility and aim to implement inter-organizational innovation.Originality/valueThe mapping of the receptive context to influence inter-organizational innovation widens the knowledge base and provides valuable insights on how inter-organizational innovation may be implemented in the loosely coupled construction industry. Furthermore, the findings broaden the discussion on clients as innovation supporters, and contribute to the debate on clients as innovation supporters, by highlighting the importance of distinguishing between different types of clients.
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| 24. |
- Hosseinnia, Ali, et al.
(författare)
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Ethane thermometry using rotational coherent anti-Stokes Raman scattering (CARS)
- 2017
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 36:3, s. 4461-4468
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Tidskriftsartikel (refereegranskat)abstract
- The complete rotational CARS (coherent anti-Stokes Raman scattering) spectrum of ethane (C2H6) has for the first time been recorded instantaneously under high spectral resolution, and the potential for thermometry has been investigated. Experiments were performed in the temperature range 292-650K in pure ethane and in binary mixtures with nitrogen. A polarization technique was used to suppress the non-resonant contribution to the CARS signal. The ethane RCARS spectra show both S- and R-branch lines, which are more closely spaced than for the well-known nitrogen spectrum and located at much smaller Raman shifts. The peak signal strength was found to be around 240 times lower for ethane than for nitrogen (at 292K). Two main approaches for ethane thermometry are evaluated, which both show high potential. The first is a method in which a spectrum with unknown temperature is fitted using a library of experimental spectra recorded at various temperatures. The second is a method based on ratios of integrated signals in different spectral regions. A theoretical model for simulation of theoretical spectra is under development.
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| 25. |
- Hosseinnia, Ali, et al.
(författare)
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Pure rotational coherent anti-Stokes Raman spectroscopy of ethylene, experiments and modelling
- 2019
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073. ; 234, s. 24-31
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Tidskriftsartikel (refereegranskat)abstract
- Rotational coherent anti-Stokes Raman spectroscopy (CARS) is an established diagnostic technique for temperature and concentration measurements in combustion-related experiments. CARS has mainly been applied on di- and tri-atomics with linear molecular symmetry, for which good agreement is achieved between experimental and theoretical spectra. Hydrocarbons have so far been less attractive for rotational CARS studies, partly because of their complex molecular symmetries making it challenging to obtain molecular parameters necessary for a successful modeling. Nevertheless, in this work we have studied the asymmetric top molecule ethylene (C2H4) using rotational CARS through experiments and theoretical modelling. Experimental spectra have been recorded at temperatures between 293 K and 804 K, and theoretical spectra have been calculated with a novel method for which the crucial temperature-dependent linewidth parameters were determined by comparison of experimental and theoretically calculated spectra. Line-mixing effects and temperature dependence of the isolated linewidths were studied using a semi-classical approach considering an exponential gap law and a scaling law. Subsequently, theoretically calculated spectra were used to evaluate the temperatures of the experimental spectra for validation of the method. The evaluated temperatures were in good agreement with thermocouple temperatures with differences up to ±7 K. Hence, this work not only investigates the potential of using rotational CARS on ethylene for diagnostic purposes, but also expands the applicability of the technique to a whole new class of molecules with asymmetric-top molecular symmetry.
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| 26. |
- Hosseinnia, Ali, et al.
(författare)
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Rotational CARS thermometry and concentration measurements in ethane-nitrogen mixtures using Fourier analysis
- 2018
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Ingår i: Journal of Raman Spectroscopy. - : Wiley. - 0377-0486. ; 49:7, s. 1096-1108
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Tidskriftsartikel (refereegranskat)abstract
- Rotational coherent anti-Stokes Raman scattering (CARS) is an established diagnostic technique for thermometry and species concentration measurements of di-atomics and tri-atomics in combustion processes; however, studies on hydrocarbon fuel molecules have been scarce. In this work, we have investigated the diagnostic potential for rotational CARS on ethane with emphasis on concentration measurements in mixtures with nitrogen. Rotational CARS spectra have periodic line structures, and because ethane and nitrogen spectra partially overlap, a novel Fourier analysis approach was developed and applied to facilitate evaluation of relative concentrations and temperatures. Instead of the standard procedure of spectral fitting using libraries of theoretically calculated spectra, the fitting was based on an experimental database of temperatures and relative ethane/nitrogen concentrations. The method was successfully demonstrated in an ethane diffusion flame where ethane, initially at room temperature, is heated downstream as well as mixed with increasing amounts of nitrogen. The evaluated temperatures and concentrations are in good agreement with computational fluid dynamic model simulations.
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| 27. |
- Karrbom Gustavsson, Tina, et al.
(författare)
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A program perspective on partnering as supply chain integration
- 2017
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Ingår i: Proceedings of the 9th Nordic Conference on Construction Economics and Organization. - Lyngby : Polyteknisk Boghandel og Forlag. - 9788750211259
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Konferensbidrag (refereegranskat)abstract
- Major complex urban development projects are challenging and put pressure on coordination, cooperation and integration between a multitude of various interdependent construction projects and supply chains. While prior studies on supply chain integration mostly concern continuous exchanges in manufacturing industries, there is less research on discontinuous exchanges in project-based supply chains. This knowledge gap has resulted in an increased interest for partnering as supply chain integration in project-based supply chains and there is a conceptual and practical framework developed for understanding partnering as a multidimensional construct including four dimensions of supply chain integration: strength, scope, duration and depth of integration. This framework is useful for investigating separate projects but fails to acknowledge the program perspective including inter-project coordination and the interdependence between different projects and supply chains in the same program.The purpose of this study is to investigate how SCI may be achieved across projects within the same program. Findings are drawn from a case study of Stockholm Royal Seaport. Each stage of Stockholm Royal Seaport can be studied as a program including a multitude of interdependent and parallel projects performed within a limited timeframe and a limited area. The findings suggest that supply chain integration between projects is as important as within projects and the theoretical implications suggest an additional dimension to the multidimensional partnering framework when taking a program perspective. Partnering as supply chain integration has a width dimension on program management level that is more challenging to manage since formal procurement and contracting mechanisms are put in place mainly at the project level, not the program level.
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| 28. |
- Le, Kim Cuong, et al.
(författare)
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Direct observation of aliphatic structures in soot particles produced in low-pressure premixed ethylene flames via online Raman spectroscopy
- 2019
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 37:1, s. 869-876
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Tidskriftsartikel (refereegranskat)abstract
- Raman spectra of soot particles were monitored in the gaseous flow extracted from the burning regions of two low-pressure premixed ethylene flames, for the first time. The flame conditions were chosen to explore the diversity of soot nanostructure in slightly sooting flames. Evaluation of the Raman spectral parameters revealed that the soot particles exhibited a strongly disordered structure and a large proportion of sp hybridization of the carbon. The appearance of sp carbon chains composing up to 30% of the total carbon content as well as an olefinic component may indicate their important role in soot nucleation and growth in low pressure ethylene flames. Hence, Raman spectroscopy of soot particles in the aerosol phase revealed that accretion and cyclization of the aliphatic carbon including sp carbon chains could thus be of importance for the initial soot growth and require more investigation.
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| 29. |
- Le, Kim Cuong, et al.
(författare)
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Raman spectroscopy of mini-CAST soot with various fractions of organic compounds: Structural characterization during heating treatment from 25 °C to 1000 °C
- 2019
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 209, s. 291-302
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Tidskriftsartikel (refereegranskat)abstract
- Soot particles undergo considerable changes in composition, morphology, as well as in internal structure during formation from the incipient particles to more mature aggregates, and still there is a lack of understanding of these mechanisms. In this study, soot produced by a mini-CAST soot generator was probed using Raman spectroscopy with focus on soot with large variation in size and fraction of organic compounds. The volatility of organic compounds and changes in internal bonding structures of the soot was surveyed by heating the samples from room temperature up to 1000 °C in a flow of inert N2 gas. The soot rich in organics showed more complex Raman spectra and stronger photoluminescence background. In particular, Raman signatures interpreted as the CH “out-of-plane” mode, ethers COC, and carbonyl CO groups were observed. During the heating treatment, these signatures disappeared, which was related to vaporization of the organics. Moreover, an enhancement of Raman band intensity of mature soot during heating treatment was observed for the first time. Our study thus brings new information on structural and compositional changes for soot during heating treatment in an inert atmosphere.
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| 30. |
- Le, Kim Cuong, et al.
(författare)
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Soot Optical Band Gap Evaluated Through In-Situ And Ex-Situ Measurements As Tracer Of Soot Evolution In Premixed Flames : Soot Optical Band Gap Evaluated Through In-Situ And Ex-Situ Measurements As Tracer Of Soot Evolution In Premixed Flames
- 2019
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Ingår i: Carbon Conference 2019.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The optical band gap has been used considerably in evaluating carbon network structures in terms of sp 2 /sp 3 sites and size of aromatic clusters. However, optical band gap determination of soot particles from optical measurements is complex due to the effects of other species including organic compounds, and the contribution of absorption from organics to the total soot absorption in the UV/visible range is often overlooked. In the present work we propose a new method for separating the optical band gap of organic compounds (E1) from that of soot (E2). We apply the method to both extinction (in situ) and absorption (ex situ) measurements at various heights in premixed laminar flat flames, and find good agreement between the methods. The band gap of soot (E1) decreases as soot ages and reaches very low values typical of large size graphitic islands, while the band gap of organics (E2) is relatively constant indicating that the organic carbon compositions in unchanged. The possibility to evaluate chemical and structural properties of the soot from the band gap information is discussed.
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| 31. |
- Malmborg, Vilhelm, et al.
(författare)
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Relating aerosol mass spectra to composition and nanostructure of soot particles
- 2019
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 142, s. 535-546
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Tidskriftsartikel (refereegranskat)abstract
- The composition and carbon nanostructure of soot are important parameters influencing health and climate effects, and the efficacy of soot mitigation technologies. We used laser-vaporization, electron-ionization aerosol mass spectrometry (or SP-AMS) to systematically investigate relationships between aerosol mass spectra, carbon nanostructure (HRTEM), and composition (thermal-optical carbon analysis) for soot with varying physicochemical properties. SP-AMS refractory black carbon concentrations (based on C≤5+ clusters) were correlated to elemental carbon (r = 0.98, p < 10−8) and equivalent black carbon (aethalometer) concentrations. The SP-AMS large carbon (C≥6+, midcarbons and fullerene carbons) fraction was inversely correlated to fringe length (r = −0.97, p = 0.028) and linearly correlated to the fraction of refractory organic carbon that partially pyrolize during heating (r = 0.89, p < 10−4). This refractory organic carbon material was incompletely detected with conventional aerosol mass spectrometry (flash vaporization at 600 °C). This suggests that (SP-AMS) refractory carbon cluster analysis provides insight to chemical bonding and nanostructures in refractory carbon materials, lowcarbons (C≤5+) indicate mature soot and large carbons indicate refractory organic carbon and amorphous nanostructures related to C5-components. These results have implications for assessments of soot particle mixing state and brown carbon absorption in the atmosphere and enable novel, on-line analysis of engineered carbon nanomaterials and soot characteristics relevant for climate and health.
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| 32. |
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| 33. |
- Nordström, Emil, et al.
(författare)
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Raman linewidth measurements using time-resolved hybrid picosecond/nanosecond rotational CARS
- 2015
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Ingår i: Optics Letters. - 0146-9592. ; 40:24, s. 5718-5721
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Tidskriftsartikel (refereegranskat)abstract
- We report an innovative approach for time-domain measurements of S-branch Raman linewidths using hybrid picosecond/nanosecond pure-rotational coherent anti-Stokes Raman spectroscopy (RCARS). The Raman coherences are created by two picosecond excitation pulses and are probed using a narrow-band nanosecond pulse at 532 nm. The generated RCARS signal contains the entire coherence decay in a single pulse. By extracting the decay times of the individual transitions, the J-dependent Raman linewidths can be calculated. Self-broadened S-branch linewidths for nitrogen and oxygen at 293 K and ambient pressure are in good agreement with previous time-domain measurements. Experimental considerations of the approach are discussed along with its merits and limitations. The approach can be extended to a wide range of pressures and temperatures and has potential for simultaneous single-shot thermometry and linewidth determination. (C) 2015 Optical Society of America
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| 34. |
- Russo, Carmela, et al.
(författare)
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Optical band gap analysis of soot and organic carbon in premixed ethylene flames: Comparison of in-situ and ex-situ absorption measurements
- 2019
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 158, s. 89-96
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Tidskriftsartikel (refereegranskat)abstract
- The similarity of in-situ and ex-situ absorption/extinction properties was found by comparing data sets obtained in premixed flat ethylene flames (C/O = 0.77); both ex-situ absorption measurements at CNR of Naples and in-situ laser extinction/absorption measurements at Lund University. The optical band gap analysis was performed as a method to separate/evaluate the contributions to the UV–Visible absorption from organic carbon and soot by selecting two spectral regions; above 685 nm where only soot is assumed to absorb radiation and below 685 nm, where both soot and organic carbons absorb. Optical band gap for soot was analyzed separately from organic carbon, obtaining their individual contribution to the spectral absorption from inception, throughout the growth region up to soot aggregation. While the optical band gap of soot strongly decreased along the flame from 1 to 0.1 eV, the band gap for organic carbons remained constant at ∼1.7–1.8 eV. By using the relationship of the optical band gap with nanostructural parameters (layer length and aromatic rings number), the average molecular weight of organic carbon around 400 u resulted rather far away from the molecular weight of 1000–2000 mass units evaluated for incipient soot consistently with the view of PAH species sticking together for particle inception.
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| 35. |
- Simonsson, Johan, et al.
(författare)
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Soot Concentrations in an Atmospheric Entrained Flow Gasifier with Variations in Fuel and Burner Configuration Studied Using Diode-Laser Extinction Measurements
- 2016
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 30:3, s. 2174-2186
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Tidskriftsartikel (refereegranskat)abstract
- Soot concentration measurements were performed using diode-laser extinction in an atmospheric air-blown entrained flow gasifier at two vertical levels. The gasifier was operated at different air-fuel equivalence ratios and with variations in fuel and burner configurations. Two fuels were investigated: wood powder and peat powder. These were burned using two burner configurations, one giving a rotating flow inside the gasifier (swirl), and one where the fuel and air were injected parallel with the gasifier axis (jet). The diode-laser measurements were performed at the wavelength 808 nm from which the soot concentrations were estimated, and additionally at 450 nm in order to gain insight into the spectral dependence of the extinction to estimate measurement quality. Additional diagnostic techniques were used, such as an electrical low-pressure impactor (ELPI) for soot size distributions and gas chromatography for species concentration measurements. The results show that wood powder produces higher soot concentrations than peat powder, especially at lower air-fuel equivalence ratios. Furthermore, the burner configuration had in general much less impact than the choice of fuel on the soot concentration.
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| 36. |
- Toth, Pal, et al.
(författare)
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Experimental and numerical study of biomass fast pyrolysis oil spray combustion : Advanced laser diagnostics and emission spectrometry
- 2019
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Ingår i: Fuel. - : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 252, s. 125-134
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this work was to move towards developing a comprehensible Computational Fluid Dynamics (CFD) model to facilitate the predictive modeling of Fast Pyrolysis Oil (FPO) spray combustion. A CFD model was implemented from the literature and results were compared to 2D data from non-intrusive optical diagnostics involving Planar Laser Induced Fluorescence of the OH radical, Mie scattering imaging and two-color pyrometry using a laboratory-scale, CH 4 /air flat-flame with an air-assist atomizer. Furthermore, flame radiation and contributions from graybody sources, chemiluminescence and soot were studied experimentally using emission spectroscopy and Laser Induced Incandescence (LII). Reasonable qualitative agreement was found between experimental and model results in terms of flame structure and temperature. Emission spectroscopy and LII results revealed and confirmed earlier observations regarding the low soot concentration of FPO spray flames; furthermore, it was shown that a significant portion of flame radiation originated from graybody char radiation and chemiluminescence from the Na-content of the FPO. These suggest that the treatment of soot formation might not be important in future computational models; however, the description of char formation and Na chemiluminescence will be important for accurately predicting temperature and radiation profiles, important from the point of e.g., large-scale power applications. Confirmed low soot concentrations are promising from an environmental point of view.
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| 37. |
- Török, Sandra, et al.
(författare)
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Investigation of the absorption Ångström exponent and its relation to physicochemical properties for mini-CAST soot
- 2018
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Ingår i: Aerosol Science and Technology. - : Informa UK Limited. - 0278-6826 .- 1521-7388. ; 52:7, s. 757-767
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a mini-CAST soot generator was used to produce soot with different optical and physicochemical characteristics. Absorption Ångström exponents (AAE) expressing the absorption wavelength dependence were assessed by multiwavelength in-situ and filter-based (aethalometer) laser extinction. The two optical techniques showed good agreement. For the chosen mini-CAST operating conditions, AAEs between 1 and 3.5 were found. Soot with high mass-fractions of organic carbon (OC) and pyrolytic carbon (PC) determined with thermal optical analysis were associated with AAEs significantly higher than 1. Heating to 250 and 500°C removed the majority of polycyclic aromatic hydrocarbons. However, the thermal-optical analysis revealed that OC and PC were abundant in the soot with AAE > 2 also after heating the aerosol. Analysis of mass absorption cross section ratios for elemental carbon and OC indicated that elevated AAEs also after heating to 500°C could be related to persistent OC and PC components and/or the refractory soot. By comparing the mini-CAST soot optical properties with soot properties derived from in-situ extinction measurements in a premixed flame, mini-CAST soot with a higher AAE could be identified as less mature soot.
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| 38. |
- Valiente Bermejo, María Asunción, 1972-, et al.
(författare)
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Effect of welding position on properties of duplex and superduplex stainless steel circumferential welds
- 2015
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Ingår i: Welding in the World. - : Springer Science and Business Media LLC. - 0043-2288 .- 1878-6669. ; 59:5, s. 693-703
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Tidskriftsartikel (refereegranskat)abstract
- The influence of welding position on properties ofduplex and superduplex stainless steel welds was studied. Circumferential pipe welds were produced using mechanised gasmetal arc welding in flat position, vertical up position and overhead position. Dilution, corrosion resistance, mechanical properties, microstructural features and weld imperfections were assessed and related to the welding position. Welds produced in flat and vertical up positions were less likely to produce porosity than those welded in overhead position, whilst underfill was not observed in overhead position welds. All the duplex pipe welds passed the corrosion test regardless of the welding position and showed sound microstructures. Under fixed arc energy conditions, welds produced in vertical up position showed the lowest dilution values whilst welds in flat position showed the highest. Excellent impact toughness values and cross tensile values were found regardless of the welding positions. Whenever possible, flat position is recommended as welds showed less proneness to porosity. Vertical up position is recommended as the second best choice.
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| 39. |
- Wu, Jian, et al.
(författare)
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Effects of carbon dioxide addition to fuel on soot evolution in ethylene and propane diffusion flames
- 2019
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 199, s. 85-95
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Tidskriftsartikel (refereegranskat)abstract
- The influence of carbon dioxide addition to the fuel on soot evolution in ethylene and propane diffusion flames was studied by optical diagnostics. The mole fraction of CO2 addition ranged from 0 to 0.5, while the flow rate of the fuel gas was kept constant for these two sets of flames. Spatial distributions of polycyclic aromatic hydrocarbons (PAHs), temperature, as well as volume fraction, primary particle size and number density of soot were observed by the methods of laser-induced fluorescence (LIF), ratio pyrometry and laser-induced incandescence (LII), respectively. It was found that the flame height decreased for ethylene flames while it was nearly constant for propane flames with increasing addition of CO2. The measurements showed a temperature reduction in the lower part but an increase in the upper part in the ethylene-based flames. By contrast, a slight temperature decrease was observed in overall propane-based flames with the addition of CO2. Similar suppression effects were observed in the total soot/PAHs loading, percentage of carbon conversion to soot, and the total number of primary soot particles regardless of the fuel type. Comparison between the total loading of soot and PAHs indicated that addition of CO2 inhibited the conversion of PAHs to soot. The results also showed that the addition of CO2 in the fuel had a small effect on the specific growth rate of soot regardless of the fuel type. Relative changes of particle surface area could reasonably well explain the shift in the peak volume fraction from the wings to the centerline with the addition of CO2 to the ethylene flames.
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| 40. |
- Wu, Jian, et al.
(författare)
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Optical investigations on particles evolution and flame properties during pulverized coal combustion in O 2 /N 2 and O 2 /CO 2 conditions
- 2019
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 251, s. 394-403
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of soot and coal/char as well as the flame properties, during pulverized coal combustion in O 2 /N 2 and O 2 /CO 2 conditions, were experimentally studied using optical diagnostics. The jet flames of pulverized coal particles were produced by using an entrained-flow reactor with optical access, and the oxygen concentrations of the gas carrying pulverized coal particles were varied between 0 and 100%. A combination of laser-induced incandescence (LII), laser-induced fluorescence (LIF), elastic laser scattering (ELS), and radiative emission detection methods was employed to characterize the spatial distributions of soot, polycyclic aromatic hydrocarbons (PAHs), coal/char, and the flame temperature. The measured results revealed that ELS signal intensity declined accompanied with the appearance of LIF and LII signals. An evolution pattern of PAHs and soot was investigated to be similar to those found in gaseous hydrocarbon diffusion flames. An abrupt expansion of the pulverized coal particle jet was observed from ELS measurement at the position where coal particle jet was ignited, which was likely attributed to the more intensive dispersion of small particles caused by a rapid elevation of the flame temperature. As the oxygen concentration increased, the ignition distance of pulverized coal particle jet became shorter and the flame temperature increased. The PAHs and soot-loaded regions were shrunk and the sooting region shifted to upstream position of the flame. Nonetheless, replacing N 2 with CO 2 tended to increase the ignition distance but lower the flame temperature. The peak LII signal, corresponding to the maximum soot volume fraction, increased to a maximum and then decreased with oxygen concentration and the intensity for the O 2 /N 2 case was far larger than for the O 2 /CO 2 case. However, the LIF signal intensities exhibited an apparent decrease with increasing oxygen concentration, and they were nearly consistent when N 2 was replaced with CO 2 , which may imply that the effect of suppressing radical formation on PAHs evolution in CO 2 atmosphere was negligible.
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| 41. |
- Zhao, Guangyu, et al.
(författare)
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Particle profiling and classification by a dual-band continuous-wave lidar system
- 2018
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Ingår i: Applied Optics. - 1559-128X. ; 57:35, s. 10164-10171
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Tidskriftsartikel (refereegranskat)abstract
- A dual-band continuous-wave (CW) light detection and ranging (lidar) system has been developed for particle classification. In this lidar system, the range-resolved atmospheric backscattering signal is recorded by an optical imaging system satisfying the Scheimpflug principle instead of the conventional time-of-flight approach. It is thus possible to employ low-cost and compact CW diode lasers, facilitating the development of a robust multiple-wavelength atmospheric lidar system that can attain high accuracy of the retrieved parameters of atmospheric particles. The present work demonstrates a dual-band Scheimpflug lidar system employing two diode lasers at 405 nm (0.5 W) and 808 nm (3.2 W). Exposures are milliseconds apart and interpolated. Measurements of various types of particles and smoke have been performed to verify the feasibility of using the present system for improved particle classification and sizing, for the situation when plumes were dilute and no significant opacity was detected.
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