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This paper expresses the views of a group of experts within the Italian Study Group on Dysphagia (GISD) concerning the role of the Audiologist–Phoniatrician in performing the dynamic endoscopic study of swallowing. This paper expresses the views of a group of experts within the Italian Study Group on Dysphagia (GISD) concerning the role of the Audiologist-Phoniatrician in performing the dynamic endoscopic study of swallowing.

The formation, growth, and oxidation of soot are studied in a set of laminar coflow diffusion flames at pressures ranging from 1 to 8 atm. The modeling approach combines detailed finite rate chemical kinetics mechanisms that model the formation of Polycyclic Aromatic Hydrocarbon (PAH) species up to pyrene, and a bivariate method of moments that describes soot particles and aggregates by their volume and surface area. The spatial distribution of soot observed experimentally and that predicted numerically are in good qualitative agreement with the peak soot volume fraction located at the flame tip and soot appearing on the flame wings and closer to the nozzle as pressure increases. A detailed analysis of the effect of hydrodynamics and mixing on soot formation is presented. We show that the scalar dissipation rate is lower for the higher pressure flames, promoting the formation of PAH species and soot. Thus, the observed increase in soot volume fraction across flames with increasing pressure is not due solely to mixture density and kinetics effects, rather is affected by hydrodynamics and mixing processes also. Similarly, our results indicate that the decrease in the scalar dissipation rate contribute to changing the location where soot forms in the flame, with soot formation occurring closer to the nozzle and outward on the flame’s wings as pressure increases. Radiative heat losses are found to lower the flame temperature, inducing a reduction of the PAH species and associated rates of soot formation. However, heat losses are responsible for a slightly longer flame, which allows for more soot. The overall effect is a modest variation of soot volume fraction if radiation is included.

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 particles in turbulent sooting flames.

We developed a novel two-step hierarchical method for the Bayesian inference of the rate parameters of a target reaction from time-resolved concentration measurements in shock tubes. The method was applied to the calibration of the parameters of the reaction of hydroxyl with 2-methylfuran, which is studied experimentally via absorption measurements of the OH radical’s concentration following shock-heating. In the first step of the approach, each shock tube experiment is treated independently to infer the posterior distribution of the rate constant and error hyper-parameter that best explains the OH signal. In the second step, these posterior distributions are sampled to calibrate the parameters appearing in the Arrhenius reaction model for the rate constant. Furthermore, the second step is modified and repeated in order to explore alternative rate constant models and to assess the effect of uncertainties in the reflected shock’s temperature. Comparisons of the estimates obtained via the proposed methodology against the common least squares approach are presented. The relative merits of the novel Bayesian framework are highlighted, especially with respect to the opportunity to utilize the posterior distributions of the parameters in future uncertainty quantification studies.

The opportunity for ignition assistance by a pulsed applied voltage is investigated in a canonical one-dimensional configuration. An incipient ignition kernel, formed by localized energy deposition into a lean mixture of methane and air at atmospheric pressure, is subjected to sub-breakdown electric fields (E/N ≈ 100 Td) by a DC potential applied across the domain, resulting in non-thermal behavior of the plasma formed during the discharge. A two-fluid approach is employed to couple thermal neutrals and ions to the non-thermal electrons. A two-temperature plasma mechanism describing gas phase combustion, excitation of neutral species, and high-energy electron kinetics is employed to account for non-thermal effects. Charged species transported from the ignition zone drift rapidly through the domain, augmenting the magnitude of the electric field in the fresh gas during the pulse through a dynamic-electrode effect, which results in an increase in the energy of the electrons in the fresh mixture with increasing time. Enhanced fuel and oxidizer decomposition due to electron impact dissociation and interaction with excited neutrals generate a pool of radicals, mostly O and H, in the fresh gas ahead of the flame’s preheat zone. In the configuration considered, the effect of the nanosecond pulse is to increase the mass of fuel burned at equivalent times relative to the unsupported ignition through enhanced radical generation, resulting in an increased heat release rate in the immediate aftermath of the pulse.

The i − V curve describes the current drawn from a flame as a function of the voltage difference applied across the reaction zone. Since combustion diagnostics and flame control strategies based on electric fields depend on the amount of current drawn from flames, there is significant interest in modeling and understanding i − V curves. We implement and apply a detailed model for the simulation of the production and transport of ions and electrons in one-dimensional premixed flames. An analytical reduced model is developed based on the detailed one, and analytical expressions are used to gain insight into the characteristics of the i − V curve for various flame configurations. In order for the reduced model to capture the spatial distribution of the electric field accurately, the concept of a dead zone region, where voltage is constant, is introduced, and a suitable closure for the spatial extent of the dead zone is proposed and validated. The results from the reduced modeling framework are found to be in good agreement with those from the detailed simulations. The saturation voltage is found to depend significantly on the flame location relative to the electrodes, and on the sign of the voltage difference applied. Furthermore, at sub-saturation conditions, the current is shown to increase linearly or quadratically with the applied voltage, depending on the flame location. These limiting behaviors exhibited by the reduced model elucidate the features of i − V curves observed experimentally. The reduced model relies on the existence of a thin layer where charges are produced, corresponding to the reaction zone of a flame. Consequently, the analytical model we propose is not limited to the study of premixed flames, and may be applied easily to others configurations, e.g. nonpremixed counterflow flames.

Deregulation affects incumbent firms through entry threats (a curse) and entry opportunities (a blessing). To separate these effects, we construct novel network-based measures of U.S. state-level bank deregulation intensity that allow us to isolate the blessing- and curse-related effects of deregulation on incumbents’ outcomes for the first time in the literature. In contrast to existing bank deregulation studies, we find that increased competition leads to higher deposit funding costs and a reduction in banks’ net interest margins and profitability. In response, banks increase their risk-taking, shift their business models, and become more likely to be acquired. Our framework and results bridge multiple literatures and support early bank deregulation theories in which reductions in bank charter values lead to increased risk-taking.

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 ≤ Re λ ≤ 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.

Summary The analysis of reactive systems in combustion science and technology relies on detailed models comprising many chemical reactions that describe the conversion of fuel and oxidizer into products and the formation of pollutants. Shock-tube experiments are a convenient setting for measuring the rate parameters of individual reactions. The temperature, pressure, and concentration of reactants are chosen to maximize the sensitivity of the measured quantities to the rate parameter of the target reaction. In this study, we optimize the experimental setup computationally by optimal experimental design in a Bayesian framework. We approximate the posterior probability density functions (pdf) using truncated Gaussian distributions in order to account for the bounded domain of the uniform prior pdf of the parameters. The underlying Gaussian distribution is obtained in the spirit of the Laplace method, more precisely, the mode is chosen as the maximum a posteriori (MAP) estimate, and the covariance is chosen as the negative inverse of the Hessian of the misfit function at the MAP estimate. The model related entities are obtained from a polynomial surrogate. The optimality, quantified by the information gain measures, can be estimated efficiently by a rejection sampling algorithm against the underlying Gaussian probability distribution, rather than against the true posterior. This approach offers a significant error reduction when the magnitude of the invariants of the posterior covariance are comparable with the size of the bounded domain of the prior. We demonstrate the accuracy and superior computational efficiency of our method for shock-tube experiments aiming to measure the model parameters of a key reaction, which is part of the complex kinetic network describing the hydrocarbon oxidation. In the experiments, the initial temperature and fuel concentration are optimized with respect to the expected information gain in the estimation of the parameters of the target reaction rate. We show that the expected information gain surface can change its “shape” dramatically according to the level of noise introduced into the synthetic data. The information that can be extracted from the data saturates as a logarithmic function of the number of experiments, and few experiments are needed when they are conducted at the optimal experimental design conditions. Furthermore, inversion of the legacy data indicates the validity and robustness of our designs. Copyright © 2016 John Wiley & Sons, Ltd.

The interaction between scales is investigated in a turbulent mixing layer. The large-scale amplitude modulation of the small scales already observed in other works depends on the crosswise location. Large-scale positive fluctuations correlate with a stronger activity of the small scales on the low speed-side of the mixing layer, and a reduced activity on the high speed-side. However, from physical considerations we would expect the scales to interact in a qualitatively similar way within the flow and across different turbulent flows. Therefore, instead of the large-scale fluctuations, the large-scale gradients modulation of the small scales has been additionally investigated. INTRODUCTION AND MOTIVATION In the present work the interaction between turbulence scales in a mixing layer is investigated at relatively high Reynolds number (1). The interaction between the large and the small scales has been the topic of several studies. Recent investigations showed that in a boundary layer the large scales of turbulence modulate the small-scale motions (2) (3). Close to the wall, large-scale positive fluctuations are associated with a stronger activity of the small-scale motions, whereas they are related with reduced small-scale activity in the outer region. The top-down interaction between large and small scales presents an important phase delay, and therefore it is not concurrent (4). These findings were based on time series from hot-wire anemometry. The interaction between scales was studied experimentally in a jet by Fiscaletti et al. (5), using hot-wire anemometry, and PIV. It was found that the small-scale signal is stronger in amplitude if it is conditioned on positive large-scale fluctuations. Surprisingly, the strength of the small-scale amplitude modulation in the spatial signal obtained with PIV was only 25% of the value obtained from the time signal from hot-wire anemometry. The elevated level of the amplitude modulation from hot-wire anemometry was attributed to the fixed spectral band filter used to obtain the large- and the small-scale signals, which does not consider the local convection velocity. Moreover, the inhomogeneous distribution of the structures of vorticity, and their preferential location in high velocity regions of the flow could explain the spatial amplitude modulation. Buxton & Ganapathisubramani (2014) (6) investigated experimentally the fully developed region of a mixing layer. They found that negative large-scale fluctuations coincide with regions characterized by a high amplitude of the small-scale signal. Large and small scales appear therefore to interact similarly to the outer region of the turbulent boundary layer. The work did not consider different crosswise locations within the mixing layer. Therefore, the first goal of the present study is the investigation of the interaction between the large and the small scales of turbulence at different crosswise locations in the mixing layer. A strong flow dependency with respect to the nature of the scale interaction, i.e. increased vs decreased small activity with positive large scale fluctuations, has been observed (Bandyopadhyay & Hussein 1984, (2)). In addition, the location within the same flow seems to affect large-scale amplitude modulation. On the other hand, this appears at conflict with the classical theories of turbulence, according to which the transfer of turbulent kinetic energy across the scales is a universal process. Then, we would expect the scale interactions to be qualitatively similar across flows. Recent findings have related the activity of the viscous scales to the large-scale shear layers within the flow ((7), (8)). Large-scale shear layers, characterized by strong velocity gradients are expected to play an important role in the cascade of turbulent kinetic energy. As a second goal of this work, we intend to examine possible interactions between the large-scale gradients (rather than the large-scale velocity used before) and the small scales of turbulence, by determining the correlation between the large-scale gradients and the local activity of the small scales (local enstrophy). METHODS

Background Advance directives (AD) offer the opportunity for goal-concordant care at the end of life (EOL). However, fewer than half of HCT recipients have a documented AD. We hypothesized that the use of a novel AD-the Stanford What Matters Most Letter (Letter AD)-developed to assess patients' values, goals, and EOL wishes would result in a greater proportion of AD completion among HCT recipients. We therefore conducted a prospective, randomized, controlled study of the traditional California AD vs. the Letter AD in adult allogeneic HCT recipients. Methods Patients >= 18 years old undergoing first allogeneic HCT at Stanford University were eligible. Prior to HCT conditioning, enrolled patients were randomly assigned to complete either the traditional California AD or the Letter AD, and all patients received a sociodemographic survey and a survey evaluating their opinions regarding the AD form they received. Patients were asked to return all research forms at the time of their transplant admission; a research assistant placed a reminder call to each patient prior to scheduled transplant. The primary endpoint was AD completion; secondary endpoints included EOL wishes as documented on the AD and patient preferences and opinions regarding the AD version they received. Results Between March 2017 and August 2018, 212 patients were eligible, of whom 126 (59.4%) were enrolled and randomized. Among the 84 who declined, the primary reason was already having an AD (N=34). The median age was 57 years (IQR 45-64); 54.8% were male; 58.7% were non-Hispanic White; and 72.3% had AML/MDS. There were no statistically significant differences in baseline socio-demographics between study arms. The overall AD completion rate was 71.6% and did not differ between the Traditional and Letter AD study arms (70.3% vs 72.6%, P=0.78). Preferences for EOL among responders are described in Table 1. The Letter AD uncovered that 66.7%, 42.2%, and 46.7% of patients actively wished to die gently/naturally, at home, and/or with hospice, respectively, whereas the traditional AD found that 62.2% wished to not prolong life if recovery was unlikely. Figure 1 portrays participant responses to the AD opinion survey; non-significant trends suggested that patients found the Letter AD favorable in terms of identifying what matters most to them, describing medical preferences to family, and stimulating thinking about the topic. Conclusion Completion rates of AD amongst allogeneic HCT recipients on this study were high and did not differ based upon AD version. Most patients wish to die naturally/do not wish to prolong care at EOL. Non-significant trends favored the Letter AD over the Traditional AD across several domains of patient preference.

Topic Significance & Study Purpose/Background/Rationale Blood and Marrow Transplantation (BMT) is a potentially curative therapy, but despite clinical advancements it continues to be associated with significant morbidity and mortality. Advance Directives (AD) ensure that patients receive the care that is consistent with their values, goals, and preferences at end of life (EOL). Yet, fewer than a quarter of BMT recipients at this Academic Medical Center have a documented AD. This leads to an increase in unnecessary treatments, care escalations, and discrepancy of care expectations which heightens distress for the patient, family, and provider. In May 2019, a nurse driven interprofessional team was assembled to conduct a performance improvement project. Methods, Intervention, & Analysis The goal was to increase the percent of completed AD for BMT recipients at this Center before transplant (Day 0), from 21% to 40% by September 2019. Through team-based problem solving, analyzation of possible causes for gaps in practice related to AD completion was performed. The identified key focus areas included: the absence of AD discussions in both the clinic and inpatient settings, lack of staff training and education, and no standard workflow for AD completion or collection. These findings were addressed in June 2019, by implementing a standard operating procedure within the BMT program for AD completion, delivery, and submission into the electronic health record. Training was also developed and provided to all BMT interprofessional teams. Findings & Interpretation Between July 2019 and September 2019, 74 patients received a transplant at this center, of those patients 30 had an AD completed by Day 0. The overall AD completion rate was 40.5% (Table 1). Furthermore, an increase in patients providing their Social Workers with a completed AD in the clinic setting was identified as well as the referrals to inpatient Spiritual Care services for assistance with AD completion. Discussion & Implications Early completion of AD offers the opportunity for goal-concordant care at EOL, and the BMT population can greatly benefit from this care. This has the potential to reduce hospitalization at the EOL, decrease ICU utilization and costly invasive interventions, increase utilization of hospice services, and promote a higher satisfaction with the quality of care.

This dissertation seeks to examine three well-known problems in three different areas of financial economics: The effects of regulation on the financial sector; the provision of incentives to limit freeriding in teams; and the lack of empirical support for the consumption-based asset pricing model. In the first essay, I address the current debate on the costs and benefits of financial regulation, and I show that financial regulation can increase bank shareholder value by reducing shareholder monitoring costs. I use a regression discontinuity design to study the effect of an unexpected decrease in small-bank reporting requirements to the Federal Reserve. Using the reporting change as a negative shock to regulatory monitoring by the Fed, I find that reduced Fed monitoring leads to a 1% loss in Tobin’s q and a 7% loss in equity market-to-book. I show that these losses come from increased internal monitoring expenditures, managerial rents, and monitoring conflicts between shareholders. My results are among the first to quantify the shareholder value of monitoring. In the second essay (with Benjamin Tengelsen and Ariel Zetlin-Jones), we re-examine the importance of separation between ownership and labor in team production models that feature free riding. In such models, conventional wisdom suggests an outsider is needed to administer incentive schemes that do not balance the budget. We analyze the ability of insiders to administer such incentive schemes in a repeated team production model with free riding when they lack commitment. Specifically, we augment a standard, repeated team production model by endowing insiders with the ability to impose group punishments which occur after team outcomes are observed but before the subsequent round of production. We extend techniques from Abreu (1986) to characterize the entire set of perfect-public equilibrium payoffs and find that insiders are capable of enforcing welfare enhancing group punishments when they are sufficiently patient. In the third essay, I re-examine an important prediction of asset pricing theory which has historically found little support in the data—that expected consumption growth and equity returns should be correlated. I first show empirically that advertising growth is a good proxy for expected consumption growth, as it predicts both consumption growth and equity returns in aggregate post-war US data. To shed light on the link between advertising growth, expected consumption, and expected returns, I then build and calibrate a dynamic model of goods market frictions where firms invest in advertising to build their customer capital (as in Gourio and Rudanko (2014)). Within the model, I show that the severity of goods market frictions is a key element to replicate the predictability patterns I observe in the data.

[Joint Meeting of the German and Italian Sections of the Combustion Institute, May 23 - 26, Sorrento, Italy] Joint Meeting of the German and Italian Sections of the Combustion Institute, May 23 - 26, Sorrento, Italy

This work deals with an investigation on the Cepstral Peak Prominence Smoothed (CPPS) as a discriminator of vocal health in continuous speech. Individual CPPS distribution and its descriptive statistics in reading and free speech acquired with a headworn microphone were investigated. Two groups of subjects were involved: 72 dysphonic and 39 control volunteers according to videostroboscopy examinations. The 95th percentile showed the highest diagnostic precision in both the speech materials (Area Under Curve of 0.86), with lower values indicating a pathological status of voice. Similar best thresholds were found for both reading and free speech (18.1 dB and 17.9 dB, respectively), but the identical phonemic contents of the reading task allowed higher sensitivity and specificity to be obtained. The voice self-assessment was also evaluated in the healthy and pathological groups by means of a questionnaire, namely the Italian version of the Voice Activity And Participation Profile. Significantly different scores were obtained by the two groups in all the sections of the questionnaire, thus highlighting that vocal problems are actually perceived by dysphonic people. Moreover, the 95th percentile resulted in a strong correlation with the sections of self-perceived voice problem and daily communication.

We investigate two methods to build a polynomial approximation of a model output depending on some parameters. The two approaches are based on pseudo-spectral projection (PSP) methods on adaptively constructed sparse grids, and aim at providing a finer control of the resolution along two distinct subsets of model parameters. The control of the error along different subsets of parameters may be needed for instance in the case of a model depending on uncertain parameters and deterministic design variables. We first consider a nested approach where an independent adaptive sparse grid PSP is performed along the first set of directions only, and at each point a sparse grid is constructed adaptively in the second set of directions. We then consider the application of aPSP in the space of all parameters, and introduce directional refinement criteria to provide a tighter control of the projection error along individual dimensions. Specifically, we use a Sobol decomposition of the projection surpluses to tune the sparse grid adaptation. The behavior and performance of the two approaches are compared for a simple two-dimensional test problem and for a shock-tube ignition model involving 22 uncertain parameters and 3 design parameters. The numerical experiments indicate that whereas both methods provide effective means for tuning the quality of the representation along distinct subsets of parameters, PSP in the global parameter space generally requires fewer model evaluations than the nested approach to achieve similar projection error. In addition, the global approach is better suited for generalization to more than two subsets of directions.

A steady, laminar stagnation flow configuration is adopted to investigate numerically the interaction between condensing aerosol particles and gas-phase transport across a canonical mixing layer. The mixing rates are varied by adjusting the velocity and length scales of the stagnation flow parametrically. The effect of mixing rates on particle concentration, polydispersity, and mean droplet diameter is explored and discussed. This numerical study reveals a complex response of the aerosol to varying flow times. Depending on the flow time, the variation of the particle concentration in response to varying mixing rates falls into one of the two regimes. For fast mixing rates, the number density and volume fraction of the condensing particles increase with residence time (nucleation regime). On the contrary, for low mixing rates, number density decreases with residence time and volume fraction reaches a plateau (condensation regime). It is shown that vapor scavenging by the aerosol phase is key to explaining the transition between these two regimes. The results reported here are general and illustrate genuine features of the evolution of aerosols forming by condensation of supersaturated vapor from heat and mass transport across mixing layers.

The effect of Damkohler 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 Damkohler numbers. A reduced chemical mechanism, which includes the soot precursor naphthalene, and a high-order method of moments are employed. At the highest Damkohler number, local extinction is negligible, while flames holes are observed in the two lowest Damkohler number cases. Compared to temperature and other species controlled by fuel oxidation chemistry, naphthalene is found to be affected more significantly by the Damkohler number. Consequently, the overall soot mass fraction decreases by more than one order of magnitude for a fourfold decrease of the Damkohler 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 Damkohler 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.

A set of tribrachial flames of n-heptane/air is simulated with finite rate chemistry and detailed transport in a realistic laminar jet configuration for which experimental data are available. The flames differ by the temperature of the unburnt mixture and stabilization height, which controls the mixture fraction gradient ahead of the flame front. The simulations reproduce the lift-off heights in the experiments, showing that the flame stabilizes further downstream as the unburnt temperature decreases. For the lowest unburnt temperature, resulting in a weak mixture fraction gradient at the tribrachial point, positive stretch along the rich premixed wing leads to an increase in the rate of chemical reaction in the whole flame. The tribrachial flame burning velocity exceeds that in the unstretched, one-dimensional flame. For the highest temperature, the flame stabilizes closest to the nozzle. Large flame tilt, large mixture fraction gradient, and small radius of curvature lead to a reduction in the heat release rate and the flame propagates slower than its one-dimensional counterpart. The observed behavior is explained with a detailed analysis of the flame geometry, differential diffusion effects, flame stretch, and transport of heat and mass from the burnt gases to the flame front.