Intensity Variations of H Alpha and N II 6 583 A Lines in the Night Sky Spectrum

Intensity variations of H alpha and N II 6 583 A lines in night sky spectru

Linearized Asymptotic Stability for Fractional Differential Equations

We prove the theorem of linearized asymptotic stability for fractional differential equations. More precisely, we show that an equilibrium of a nonlinear Caputo fractional differential equation is asymptotically stable if its linearization at the equilibrium is asymptotically stable. As a consequence we extend Lyapunov's first method to fractional differential equations by proving that if the spectrum of the linearization is contained in the sector \{\lambda \in \C : |\arg \lambda| > \frac{\alpha \pi}{2}\} where $\alpha > 0$ denotes the order of the fractional differential equation, then the equilibrium of the nonlinear fractional differential equation is asymptotically stable

Interpersonal emotion regulation: a review of social and developmental components

A staple theme in clinical psychology, emotion regulation, or the ability to manage one's emotions, is directly linked with personal wellbeing and the ability to effectively navigate the social world. Until recently, this concept has been limited to a focus on intrapersonal processes, such as suppression. Less emphasis has been placed on developmental, social, and cultural aspects of emotion regulation. We argue here that as social beings, our engagement in emotion regulation may often occur interpersonally, with trusted others helping us to regulate our emotions. This review will highlight recent research on interpersonal emotion regulation processes.Dr Hofmann receives financial support from the Alexander von Humboldt Foundation (as part of the Humboldt Prize), NIH/NCCIH (R01AT007257), NIH/NIMH (R01MH099021, U01MH108168), and the James S. McDonnell Foundation 21st Century Science Initiative in Understanding Human Cognition - Special Initiative. He receives compensation for his work as an advisor from the Palo Alto Health Sciences and for his work as a Subject Matter Expert from John Wiley & Sons, Inc. and SilverCloud Health, Inc. He also receives royalties and payments for his editorial work from various publishers. (Alexander von Humboldt Foundation; R01AT007257 - NIH/NCCIH; R01MH099021 - NIH/NIMH; U01MH108168 - NIH/NIMH; James S. McDonnell Foundation 21st Century Science Initiative in Understanding Human Cognition - Special Initiative)Accepted manuscrip

Analysis of Markers for Combustion Mode and Heat Release in MILD Combustion Using DNS Data

Various commonly used markers for heat release are assessed using direct numerical simulation (DNS) data for Moderate or Intense Low-oxygen Dilution (MILD) combustion to find their suitability for non-premixed MILD combustion. The laser induced fluorescence (LIF) signals of various markers are synthesised from the DNS data to construct their planar (PLIF) images which are compared to the heat release rate images obtained directly from the DNS data. The local ${\rm OH}$ values in heat releasing regions are observed to be very small compared to the background level coming from unreacted mixture diluted with exhaust gases. Furthermore, these values are very much smaller compared to those in burnt regions. This observation rises questions on the use of ${\rm OH}$-PLIF for MILD combustion. However, the chemiluminescent image obtained using ${\rm OH^*}$ is shown to correlate well with the heat release. Two-scalar based PLIF markers, $\left({\rm OH} \times {\rm CH_2O}\right)$ and $\left({\rm H} \times {\rm CH_2O}\right)$, correlate well with the heat release. Flame index (${\rm FI}$) and chemical explosive mode (CEMA) analyses are used to identify premixed and non-premixed regions in MILD combustion. Although there is some agreement between the CEMA and ${\rm FI}$ results, large discrepancies are still observed. The schlieren images deduced from the DNS data showed that this technique can be used for a quick and qualitative identification of MILD combustion before applying expensive laser diagnostics.Qualcomm European Research Studentship Fund in Technolog

Autoignition and flame propagation in non-premixed MILD combustion

Direct Numerical Simulation (DNS) data of Moderate or Intense Low-oxygen Dilution (MILD) combustion are analysed to gather insights on autoignition and flame propagation in MILD combustion. Unlike in conventional combustion, the chemical reactions occur over a large portion of the computational domain. The presence of ignition and flame propagation and their coexistence are studied through spatial and statistical analyses of the convective, diffusive and chemical effects in the species transport equations. Autoignition is observed in regions with lean mixtures because of their low ignition delay times and these events propagate into richer mixtures either as a flame or ignition. This is found to be highly dependent on the mixture fraction length scale, $\ell_Z$, and autoignition is favoured when $\ell_Z$ is small.N.A.K.D. acknowledges the financial support of the Qualcomm European Research Studentship Fund in Technology. This work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk) using computing time provided by EPSRC under the project number e419 and the UKCTRF (e305)

Multiscale analysis of turbulence-flame interaction in premixed flames

Multiscale analysis of turbulence-flame interaction is performed using direct numerical simulation (DNS) data of premixed flames. Bandpass filtering method is used to educe turbulent eddies of various sizes and their vorticity and strain rate fields. The vortical structures at a scale of L ω are stretched strongly by the most extensional principal strain rate of eddies of scale 4L ω , which is similar to the behaviour in non-reacting turbulence. Hence, combustion does not influence the physics of vortex stretching mechanism. The fractional contribution from eddies of size L s to the total tangential strain rate is investigated. The results highlight that eddies larger than two times the laminar flame thermal thickness contributes predominantly to flame straining and eddies smaller than 2δ th contributes less than 10% to the total tangential strain rate for turbulence intensities, from u′/s L = 1.41 to u′/s L = 11.25, investigated here. The cutoff scale identified through this analysis is larger than the previous propositions and the implication of this finding to subgrid scale premixed combustion modelling is discussed.N.A.K.D. acknowledges the financial support of the Qualcomm European Research Studentship Fund in Technology. N. C. acknowledges the financial support of EPSRC