Quantitative Statistical Stability for the Equilibrium States of Piecewise Partially Hyperbolic Maps

We consider a class of endomorphisms which contains a set of piecewise partially hyperbolic dynamics semi-conjugated to non-uniformly expanding maps. The aimed transformation preserves a foliation which is almost everywhere uniformly contracted with possible discontinuity sets, which are parallel to the contracting direction. We apply the spectral gap property and the $\zeta$-H\"older regularity of the disintegration of its physical measure to prove a quantitative statistical stability statement. More precisely, under deterministic perturbations of the system of size $\delta$, we show that the physical measure varies continuously with respect to a strong $L^\infty$-like norm. Moreover, we prove that for certain interesting classes of perturbations its modulus of continuity is $O(\delta^\zeta \log \delta)$.Comment: In this version, we generalized some definitions and results. We also improve the readability, corrected some typos and fix the bibliograph

Equilibrium States for Random Zooming Systems

In this work, we introduce the notion of random zooming systems and prove the existence of equilibrium states for which we call random zooming potentials, that include the hyperbolic ones, possibly with the presence of a critical set. The proof follows ideas of the work [4]. With a mild condition, we obtain uniqueness. We also prove that the classes of random zooming potentials and random hyperbolic potentials are equivalent and also contain the null potential, giving measures of maximal entropy

An experimental and modeling study of acetylene-dimethyl ether mixtures oxidation at high-pressure

The oxidation of acetylene (as soot precursor) and dimethyl ether (DME, as a promising fuel additive) mixtures has been analyzed in a tubular flow reactor, under high-pressure conditions (20, 40 and 60 bar), in the 450–1050 K temperature range. The effect of varying the air excess ratio (λ≈0.7, 1 and 20) and the percentage of DME with respect to acetylene (10 and 40%) has been analyzed from both experimental and modeling points of view. The addition of DME modifies the composition of the radical pool, increasing the production of OH radicals which cause a shift in the onset temperature for C2H2 conversion to lower temperatures; the higher the amount of DME, the lower the temperature. The presence of DME favors the oxidation of C2H2 towards products such as CO and CO2, eliminating carbon from the paths that lead to the formation of soot. On the other hand, in the presence of C2H2, DME begins to be consumed at temperatures higher than those required for the high-pressure oxidation of neat DME, around 175–200 K more. Consequently, the negative temperature coefficient (NTC) region characteristic of this compound at low temperatures is not observed under those conditions. However, an additional analysis of the influence of DME inlet concentration (at 20 bar and λ=1) indicates that, if the amount of DME in the mixture is increased to 500 ppm and more (700 or 1000 ppm), the reaction pathways responsible for this high DME reactivity at low temperatures become more relevant and the NTC region can now be observed

Is plastidic glutamine synthetase essential for C-3 plants? A tale of photorespiratory mutants, ammonium tolerance and conifers

[EN] Agriculture faces the considerable challenge of having to adapt to a progressively changing climate (including the increase in CO2 levels and temperatures); environmental impact must be reduced while at the same time crop yields need to be maintained or increased to ensure food security. Under this scenario, increasing plants' nitrogen (N) use efficiency and minimizing the energy losses associated with photorespiration are two goals of crop breeding that are long sought after. The plastidic glutamine synthetase (GS2) enzyme stands at the crossroads of N assimilation and photorespiration, and is therefore a key candidate for the improvement of crop performance. The GS2 enzyme has long been considered essential for angiosperm survival under photorespiratory conditions. Surprisingly, in Arabidopsis GS2 is not essential for plant survival, and its absence confers tolerance towards ammonium stress, which is in conflict with the idea that NH4+ accumulation is one of the main causes of ammonium stress. Altogether, it appears that the 'textbook' view of this enzyme must be revisited, especially regarding the degree to which it is essential for plant growth under photorespiratory conditions, and the role of NH4+ assimilation during ammonium stress. In this article we open the debate on whether more or less GS2 is a desirable trait for plant productivity.This research was funded by the Basque Government (IT932-16), the Spanish State Research Agency (AEI) (PID2020-113385RB-I00 and RTI2018-093571-B-100 co-funded by FEDER, EU), Junta de Andalucia (P20_00036 PAIDI 2020/FEDER, UE) and the project US-1256179 grant from Junta de Andalucia, FEDER and Universidad de Sevilla

Influence of SO2 on the Fuel Conversion Scheme. Implication for Soot Emissions

This work includes an experimental and modeling study of whether sulfur dioxide (SO2), typically present in the recirculated flue gas, can inhibit or promote the overall fuel conversion process in a combustion system, with special attention on SO2 implication for soot emissions and the possible reduction of this pollutant

Sufficient conditions on the continuous spectrum for ergodic Schr\"odinger Operators

We study the spectral types of the families of discrete one-dimensional Schr\"odinger operators $\{H_\omega\}_{\omega\in\Omega}$, where the potential of each $H_\omega$ is given by $V_\omega(n)=f(T^n\omega)$ for $n\in\mathbb{Z}$, $T$ is an ergodic homeomorphism on a compact space $\Omega$ and $f:\Omega\rightarrow\mathbb{R}$ is a continuous function. We show that a generic operator $H_\omega\in \{H_\omega\}_{\omega\in\Omega}$ has purely continuous spectrum if $\{T^n\alpha\}_{n\geq0}$ is dense in $\Omega$ for a certain $\alpha\in\Omega$. We also show the former result assuming only that $\{\Omega, T\}$ satisfies topological repetition property ($TRP$), a concept introduced by Boshernitzan and Damanik (arXiv:0708.1263v1). Theorems presented in this paper weaken the hypotheses of the cited research and allow us to reach the same conclusion as those authors. We also provide a proof of Gordon's lemma, which is the main tool used in this work

Methyl Formate: an Experimental and Kinetic Study of its Oxidation at High-Pressure

An experimental and kinetic modeling study of the influence of pressure on the oxidation of methyl formate (MF) has been performed in the 1-60 bar pressure range. The influence of stoichiometry, temperature, pressure and presence of NO on the conversion of MF, and on the formation of the main products, has been analyzed