Investigation of the soot formation in ethylene laminar diffusion flames when diluted with helium or supplemented by hydrogen

A new optical diagnostic technique has been used to measure the spatially distributed temperatures, soot diameters, and soot volume fractions in several different ethylene laminar diffusion flames to investigate the effect of adding hydrogen and helium on the soot formation. The test results show that adding hydrogen increases the flame temperature in all regions, while adding helium does not significantly affect the flame temperature in the reaction region but does increase the flame temperature elsewhere. The flame heights when adding helium and hydrogen can be calculated using the correlation introduced by Roper if the ethylene diffusion coefficient is used. This indicates that the flame height is determined by the diffusion of ethylene molecules when the hydrogen fraction is below 20%. It was also found that either adding helium or hydrogen does not significantly affect the soot diameter but does reduce the soot volume fraction. A total of 20% of helium addition by volume was measured to reduce the total soot number by 19%, while a total of 20% of hydrogen addition reduced the total soot number by 23%. In comparison, replacing the hydrocarbon with hydrogen is much more effective in reducing soot formation. Replacement of 25% ethylene by hydrogen was measured to reduce the total soot number by 66%. Apart from demonstrating the influence of hydrogen and helium on ethylene diffusion flames, these measurements provide additional data for modelers of diffusion flames, especially those with an interest in the formation of particulate matter. © 2014 American Chemical Society

Measurement of the spatially distributed temperature and soot loadings in a laminar diffusion flame using a Cone-Beam Tomography technique

A new low-cost optical diagnostic technique, called Cone Beam Tomographic Three Colour Spectrometry (CBT-TCS), has been developed to measure the planar distributions of temperature, soot particle size, and soot volume fraction in a co-flow axi-symmetric laminar diffusion flame. The image of a flame is recorded by a colour camera, and then by using colour interpolation and applying a cone beam tomography algorithm, a colour map can be reconstructed that corresponds to a diametral plane. Look-up tables calculated using Planck's law and different scattering models are then employed to deduce the temperature, approximate average soot particle size and soot volume fraction in each voxel (volumetric pixel). A sensitivity analysis of the look-up tables shows that the results have a high temperature resolution but a relatively low soot particle size resolution. The assumptions underlying the technique are discussed in detail. Sample data from an ethylene laminar diffusion flame are compared with data in the literature for similar flames. The comparison shows very consistent temperature and soot volume fraction profiles. Further analysis indicates that the difference seen in comparison with published results are within the measurement uncertainties. This methodology is ready to be applied to measure 3D data by capturing multiple flame images from different angles for non-axisymmetric flame. © 2013 Elsevier Ltd

Analysis of the particulate emissions and combustion performance of a direct injection spark ignition engine using hydrogen and gasoline mixtures

Three different fractions (2%, 5%, and 10% of stoichiometric, or 2.38%, 5.92%, and 11.73% by energy fraction) of hydrogen were aspirated into a gasoline direct injection engine under two different load conditions. The base fuel was 65% iso-octane, and 35% toluene by volume fraction. Ignition sweeps were conducted for each operation point. The pressure traces were recorded for further analysis, and the particulate emission size distributions were measured using a Cambustion DMS500. The results indicated a more stable and faster combustion as more hydrogen was blended. Meanwhile, a substantial reduction in particulate emissions was found at the low load condition (more than 95% reduction either in terms of number concentration or mass concentration when blending 10% hydrogen). Some variation in the results occurred at the high load condition, but the particulate emissions were reduced in most cases, especially for nucleation mode particulate matter. Retarding the ignition timing generally reduced the particulate emissions. An engine model was constructed using the Ricardo WAVE package to assist in understanding the data. The simulation reported a higher residual gas fraction at low load, which explained the higher level of cycle-by-cycle variation at the low load

Cycle-to-cycle variation analysis of two-colour PLIF temperature measurements calibrated with laser induced grating spectroscopy in a firing GDI engine

In-cylinder temperatures and their cyclic variations strongly influence many aspects of internal combustion engine operation, from chemical reaction rates determining the production of NOx and particulate matter to the tendency for auto-ignition leading to knock in spark ignition engines. Spatially resolved measurements of temperature can provide insights into such processes and enable validation of Computational Fluid Dynamics simulations used to model engine performance and guide engine design. This work uses a combination of Two-Colour Planar Laser Induced Fluorescence (TC-PLIF) and Laser Induced Grating Spectroscopy (LIGS) to measure the in-cylinder temperature distributions of a firing optically accessible spark ignition engine. TC-PLIF performs 2-D temperature measurements using fluorescence emission in two different wavelength bands but requires calibration under conditions of known temperature, pressure and composition. Here the TC-PLIF technique is calibrated in-situ using high precision (<1%) LIGS point measurements. Temperature distributions were recorded during the compression stroke for fired operation with Direct Injection and with Plenum Fuel Injection of three two-component fuels containing toluene and iso-octane. Temperature inhomogeneity was observed for all fuels and injection strategies, with mm-scale regions having temperatures up to 10% higher than the local environment. Charge cooling of 3% due to direct injection was resolved. Proper Orthogonal Decomposition (POD) was used to quantify the cycle-to-cycle variation of the temperature data. Low-order POD modes featured most of the cyclic variation in temperature and the corresponding mode coefficients were used to investigate correlations with combustion analysis, fuel injection strategies and toluene content of the fuel. Additionally, the low-order POD mode coefficients provided an opportunity to identify cycles containing local hotspots or outlier measurements

Additional file 1: of Effect of treatment with a JAK2-selective inhibitor, fedratinib, on bone marrow fibrosis in patients with myelofibrosis

Table S1. Changes in BMF according to baseline characteristics and clinical response

Additional file 2: of Effect of treatment with a JAK2-selective inhibitor, fedratinib, on bone marrow fibrosis in patients with myelofibrosis

Figure S1. Scatter plots depicting the distribution of WBC levels (A), spleen size changes (B), and haemoglobin levels (C) in individual patients at each treatment cycle based on BMF status

Phospho-Akt mediates synergy observed between allosteric Akt inhibitor, KIN001-102, and PKC412.

<p>Immunoblots of protein lysates prepared from MOLM14-luc+ cells treated for 2 hours with PKC412 (40 nM), KIN001-102 (165, 330, 660 nM), or a combination of the two agents in the presence of 50% SCM. Data shown are representative of two independent experiments in which similar results were achieved.</p

Effects of PKC412 and KIN001-102, alone and combined, on MOLM14-luc+ cell cycle progression (following 24 hours of treatment) and apoptosis (following 48 hours of treatment) when cells are cultured in the presence of 50% HS-5 SCM.

<p>Details of the assays used for these studies are provided in the Materials and Methods section.</p

Ability of Akt inhibitors to positively combine with PKC412 or AC220 against AML patient samples in the presence of cytoprotective SCM.

<p>(A) Approximately two-day proliferation study performed with a selective Akt inhibitor in combination with PKC412 in the presence of HS-5 SCM against mutant FLT3-positive AML#2. (B) Approximately two-day combination studies: AC220 (0.4 nM) +/− selective AKT inhibitors (660 nM) against MOLM14-luc+ cells in the presence of 50% HS-5 SCM. (C) Approximately two-day combination studies: AC220 (0.4 nM) +/− selective AKT inhibitors (660 nM) against MOLM14-luc+ cells in the presence of RPMI+10% FBS. (D) Approximately two-day combination studies: PKC412 (40 nM)+/− selective AKT inhibitors (660 nM) against primary AML patient cells in the presence of 50% HS-5 SCM. (E) Approximately two-day combination studies: AC220 (0.4 nM) +/− selective AKT inhibitors (660 nM) against primary AML patient cells in the presence of 50% SCM. (F) Ability of Akt inhibitors to positively combine with PKC412 or AC220 against primary AML cells in the presence of cytoprotective SCM. Patient information is provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056473#pone.0056473.s010" target="_blank">Table S1</a>.</p

Selective inhibitors of AKT positively combine with PKC412 in the presence of adherent HS-5 stroma against MOLM14-luc+ cells.

<p>(A) Approximately two-day proliferation study performed with MOLM14-luc+ cells cultured in the presence of adherent HS-5 stroma testing the combination of PKC412 and KIN001-102 versus each agent alone. (B) MOLM14-luc+ cells cultured in the presence of adherent HS-5 stroma for approximately two days: PKC412 (40 nM)+/− Akt inhibitors (660 nM). (C) Approximately two-day PKC412 treatment of MOLM14-luc+ cells cultured in the absence and presence of human stroma. (D) Approximately two-day treatment of adherent HS-5 stroma: PKC412 (40 nM) +/− Akt inhibitors (660 nM). (E) Calcusyn combination indices derived from 4-point concentration proliferation experiments. The cut-off for nearly additive effects (C.I.: 1.1) is marked by a dashed line.</p