Physical lumping methods for developing linear reduced models for high speed propulsion systems

In gasdynamic systems, information travels in one direction for supersonic flow and in both directions for subsonic flow. A shock occurs at the transition from supersonic to subsonic flow. Thus, to simulate these systems, any simulation method implemented for the quasi-one-dimensional Euler equations must have the ability to capture the shock. In this paper, a technique combining both backward and central differencing is presented. The equations are subsequently linearized about an operating point and formulated into a linear state space model. After proper implementation of the boundary conditions, the model order is reduced from 123 to less than 10 using the Schur method of balancing. Simulations comparing frequency and step response of the reduced order model and the original system models are presented

Effect of hydrogen addition on the consumption speed of lean premixed laminar methane flames exposed to combined strain and heat loss

This study presents a numerical analysis of the impact of hydrogen addition on the consumption speed of premixed lean methane-air laminar flames exposed to combined strain and heat loss. Equivalence ratios of 0.9, 0.7, and 0.5 with fuel mixture composition ranging from pure methane to pure hydrogen are considered to cover a wide range of conditions in the lean region. The 1-D asymmetric counter-flow premixed laminar flame aCFPF with heat loss on the product side is considered as a flamelet configuration that represents an elementary unit of a turbulent flame and the consumption speed is used to characterize the effect of strain and heat loss. Due to the ambiguity in the definition of the consumption speed of multi-component mixtures, two definitions are compared. The definition of the consumption speed based on the heat release results in lower values of the stretched flame speed and even an opposite response to strain rate for some methane-hydrogen-air mixtures compared to the definition based on the fuel consumption. Strain rate leads to an increase in the flame speed for the lean methane-hydrogen mixtures, reaching a maximum value after which the flame speed decreases with strain rate. Heat loss decreases the stretched flame speed and leads to a sooner extinction of the flamelet due to combined strain and heat loss. Hydrogen addition and equivalence ratio significantly impact the maximum consumption speed and the flame response to combined strain rate and heat loss. The effect of hydrogen on the thermo-diffusive properties of the mixture, characterized by the Zel'dovich number and the effective Lewis number, are also analyzed and related to the effect on the consumption speed. Two definitions of the Lewis number of the multi-component fuel mixture are evaluated against the results from the aCFPF.Comment: Submitted to journal Combustion Theory and Modelling - Manuscript ID TCTM-2022-06-6

Allocation de ressources pour la localisation non-cohérente par radar MIMO

National audienceOn considère un réseau de radars MIMO dont on cherche à déterminer la meilleure répartition de largeurs de bande et de puissance entre les différentes antennes émettrices en vue d’obtenir une certaine précision de la localisation d’une cible unique. Plus précisément, on s’intéresse ici à l’allocation optimale de bande seule, ainsi qu’à l’allocation optimale conjointement de bande et de puissance. Cette allocation s’effectue par la minimisation de la borne de Cramér-Rao. Le problème d’optimisation non-convexe obtenu est résolu par un algorithme de programmation par différence de fonctions convexes. Les résultats numériques montrent que l’allocation conjointe fournit les meilleures performances, et que d’autre part l’allocation de bande joue un rôle prépondérant dans ces performances. De plus, une borne inférieure sur la borne de Cramér-Rao optimale théorique, difficilement calculable, a également été définie, qui montre la qualité de la solution quasi-optimale

Congenital anomalies from a physics perspective. The key role of "manufacturing" volatility

Genetic and environmental factors are traditionally seen as the sole causes of congenital anomalies. In this paper we introduce a third possible cause, namely random "manufacturing" discrepancies with respect to ``design'' values. A clear way to demonstrate the existence of this component is to ``shut'' the two others and to see whether or not there is remaining variability. Perfect clones raised under well controlled laboratory conditions fulfill the conditions for such a test. Carried out for four different species, the test reveals a variability remainder of the order of 10%-20% in terms of coefficient of variation. As an example, the CV of the volume of E.coli bacteria immediately after binary fission is of the order of 10%. In short, ``manufacturing'' discrepancies occur randomly, even when no harmful mutation or environmental factors are involved. Not surprisingly, there is a strong connection between congenital defects and infant mortality. In the wake of birth there is a gradual elimination of defective units and this screening accounts for the post-natal fall of infant mortality. Apart from this trend, post-natal death rates also have humps and peaks associated with various inabilities and defects.\qL In short, infant mortality rates convert the case-by-case and mostly qualitative problem of congenital malformations into a global quantitative effect which, so to say, summarizes and registers what goes wrong in the embryonic phase. Based on the natural assumption that for simple organisms (e.g. rotifers) the manufacturing processes are shorter than for more complex organisms (e.g. mammals), fewer congenital anomalies are expected. Somehow, this feature should be visible on the infant mortality rate. How this conjecture can be tested is outlined in our conclusion.Comment: 43 pages, 9 figure

What faces reveal : a novel method to identify patients at risk of deterioration using facial expressions

Objectives: To identify facial expressions occurring in patients at risk of deterioration in hospital wards. Design: Prospective observational feasibility study. Setting: General ward patients in a London Community Hospital, United Kingdom. Patients: Thirty-four patients at risk of clinical deterioration. Interventions: A 5-minute video (25 frames/s; 7,500 images) was recorded, encrypted, and subsequently analyzed for action units by a trained facial action coding system psychologist blinded to outcome. Measurements and Main Results: Action units of the upper face, head position, eyes position, lips and jaw position, and lower face were analyzed in conjunction with clinical measures collected within the National Early Warning Score. The most frequently detected action units were action unit 43 (73%) for upper face, action unit 51 (11.7%) for head position, action unit 62 (5.8%) for eyes position, action unit 25 (44.1%) for lips and jaw, and action unit 15 (67.6%) for lower face. The presence of certain combined face displays was increased in patients requiring admission to intensive care, namely, action units 43 + 15 + 25 (face display 1, p < 0.013), action units 43 + 15 + 51/52 (face display 2, p < 0.003), and action units 43 + 15 + 51 + 25 (face display 3, p < 0.002). Having face display 1, face display 2, and face display 3 increased the risk of being admitted to intensive care eight-fold, 18-fold, and as a sure event, respectively. A logistic regression model with face display 1, face display 2, face display 3, and National Early Warning Score as independent covariates described admission to intensive care with an average concordance statistic (C-index) of 0.71 (p = 0.009). Conclusions: Patterned facial expressions can be identified in deteriorating general ward patients. This tool may potentially augment risk prediction of current scoring systems

Application of mathematical and machine learning techniques to analyse eye tracking data enabling better understanding of children’s visual cognitive behaviours

In this research, we aimed to investigate the visual-cognitive behaviours of a sample of 106 children in Year 3 (8.8 ± 0.3 years) while completing a mathematics bar-graph task. Eye movements were recorded while children completed the task and the patterns of eye movements were explored using machine learning approaches. Two different techniques of machine-learning were used (Bayesian and K-Means) to obtain separate model sequences or average scanpaths for those children who responded either correctly or incorrectly to the graph task. Application of these machine-learning approaches indicated distinct differences in the resulting scanpaths for children who completed the graph task correctly or incorrectly: children who responded correctly accessed information that was mostly categorised as critical, whereas children responding incorrectly did not. There was also evidence that the children who were correct accessed the graph information in a different, more logical order, compared to the children who were incorrect. The visual behaviours aligned with different aspects of graph comprehension, such as initial understanding and orienting to the graph, and later interpretation and use of relevant information on the graph. The findings are discussed in terms of the implications for early mathematics teaching and learning, particularly in the development of graph comprehension, as well as the application of machine learning techniques to investigations of other visual-cognitive behaviours.Peer reviewe

Analysis of the interaction between tryptophan-related compounds and ATP-binding cassette transporter G2 (ABCG2) using targeted metabolomics

ATP-binding cassette transporter G2 (ABCG2) is involved in the secretion of several compounds in milk. The in vitro and in vivo interactions between tryptophan-related compounds and ABCG2 were investigated. The tryptophan metabolome was determined by liquid chromatography-tandem mass spectrometry in milk and plasma from wild-type and Abcg2-/- mice as well as dairy cows carrying the ABCG2 Y581S polymorphism (Y/S) and noncarrier animals (Y/Y). The milk-to-plasma ratios of tryptophan, kynurenic acid, kynurenine, anthranilic acid, and xanthurenic acid were higher in wild-type mice than in Abcg2-/- mice. The ratio was 2-fold higher in Y/S than in Y/Y cows for kynurenine. In vitro transport assays confirmed that some of these compounds were in vitro substrates of the transporter and validated the differences observed between the two variants of the bovine protein. These findings show that the secretion of metabolites belonging to the kynurenine pathway into milk is mediated by ABCG2.SIThis study was supported by the research projects AGL2015-65626-R (MINECO/FEDER, UE) and RTI2018-100903-B-I00 (AEI/FEDER, UE), predoctoral grants from the Ministry of Economy, Industry, and Competitiveness (BES-2016-077235 grant to AMGL), and grants from the Spanish Ministry of Education, Culture, and Sport (FPU14/05131 grant to DGM). Funding was also obtained from a research contract for OJP from the Spanish Health Institute Carlos III (CPII16/00027

Caractérisation mécanique de revêtements sol-gel hybrides

Nous avons développé une solution sol-gel hybride organique-inorganique qui, après application par trempé ou pulvérisation et suivi d’une étape de cuisson, permet d’apporter une protection contre la corrosion. Cette solution a été mise au point afin de pouvoir remplacer un acier inox 316L par un couple « inox 430 + dépôt sol-gel » tout en conservant les mêmes propriétés électrochimiques. En parallèle à l’étude des propriétés électrochimiques, nous avons développé une méthodologie pour caractériser les propriétés mécaniques du revêtement (dureté, module d’élasticité, ténacité) ainsi que son adhérence sur le substrat

Cancer Informatics for Cancer Centers (CI4CC): Building a Community Focused on Sharing Ideas and Best Practices to Improve Cancer Care and Patient Outcomes.

Cancer Informatics for Cancer Centers (CI4CC) is a grassroots, nonprofit 501c3 organization intended to provide a focused national forum for engagement of senior cancer informatics leaders, primarily aimed at academic cancer centers anywhere in the world but with a special emphasis on the 70 National Cancer Institute-funded cancer centers. Although each of the participating cancer centers is structured differently, and leaders' titles vary, we know firsthand there are similarities in both the issues we face and the solutions we achieve. As a consortium, we have initiated a dedicated listserv, an open-initiatives program, and targeted biannual face-to-face meetings. These meetings are a place to review our priorities and initiatives, providing a forum for discussion of the strategic and pragmatic issues we, as informatics leaders, individually face at our respective institutions and cancer centers. Here we provide a brief history of the CI4CC organization and meeting highlights from the latest CI4CC meeting that took place in Napa, California from October 14-16, 2019. The focus of this meeting was "intersections between informatics, data science, and population science." We conclude with a discussion on "hot topics" on the horizon for cancer informatics