Distributed tabulation of flamelet lookup tables

One of the fundamental questions in combustion simulation is how to account for detailed chemistry effects, while controlling both the error of the chemical scheme and the computational cost. Combustion chemistry is important for resolving processes such as flame propagation and pollutant formation, which are non-linear processes that can be computationally expensive. The direct solution of the governing equations of turbulent reacting flows can be prohibitively expensive as the chemical integration is often stiff. Tabulated chemistry methods with flamelet modelling emerge as an alternative to perform direct integration of the chemical source terms and has been extended to a wide range of conditions [1]. In flamelet methods, the chemical time scale is assumed smaller than the time scales of the turbulence, so the flame structure is not affected by the turbulence. In flamelet methods, the thermochemical states of the flame are computed in a preprocessing step, and these values are retrieved from a lookup table loaded into memory at the beginning of the simulation. The flame structure can be recovered through the use of controlling variables, which represent dimensions along the multidimensional space of the flame manifold

Irregular self-similar configurations of shock-wave impingement on shear layers

An oblique shock impinging on a shear layer that separates two uniform supersonic streams, of Mach numbers M1 and M2, at an incident angle σi can produce regular and irregular interactions with the interface. The region of existence of regular shock refractions with stable flow structures is delineated in the parametric space (M1,M2,σi) considering oblique-shock impingement on a supersonic vortex sheet of infinitesimal thickness. It is found that under supercritical conditions, the oblique shock fails to deflect both streams consistently and to provide balanced flow properties downstream. In this circumstance, the flow renders irregular configurations which, in the absence of characteristic length scales, exhibit self-similar pseudosteady behaviours. These cases involve shocks moving upstream at constant speed and increasing their intensity to comply with equilibrium requirements. Differences in the variation of propagation speed among the flows yield pseudosteady configurations that grow linearly with time. Supercritical conditions are described theoretically and reproduced numerically using highly resolved inviscid simulation

Body mass index but not physical activity level moderates lowered cardiac baroreflex sensitivity in people living with HIV

International Journal of Exercise Science 16(2): 700-709, 2023. Reduced cardiac baroreflex sensitivity (cBRS) is an autonomic marker associated with a worse cardiovascular prognosis. Whether cBRS is lowered in people living with HIV (PLHIV) is yet unclear, as well as potential moderator effects of body mass index (BMI) or physical activity (PA) level. The present study aims to compare the spontaneous cBRS in PLHIV vs. HIV-uninfected controls, and to determine among PLHIV the relationship between cBRS vs. body mass index (BMI) and PA level. Total, upward (cBRS+), and downward (cBRS-) cBRS gains were assessed using the sequential method from beat-to-beat blood pressure at rest in 16 PLHIV (46.5±8.4 years) under antiretroviral therapy for at least 6 months, and 16 HIV-uninfected controls (CTL; 42.1±8.0 years). PA level was assessed by the Physical Activity Questionnaire (IPAQ short version) overall score. PLHIV showed lower total cBRS (8.7±3.1 vs. 15.3±7.7 ms.mmHg-1; p \u3c 0.01), cBRS+ (9.2±4.9 vs. 16.0±6.8 ms.mmHg-1; p \u3c 0.01) and cBRS- (9.5±4.9 vs. 15.3±9.3 ms.mmHg-1; p \u3c 0.01) vs. CTL. No between-group difference was found for BMI (PLHIV: 25.2±2.6 vs. CTL: 26.8±3.2 kg.m-2; p \u3e 0.05) or IPAQ score (PLHIV: 2.4±1.0 vs. CTL: 2.0±1.4; p \u3e 0.05). In PLHIV, total cBRS was inversely correlated vs. BMI (r = -0.44; p = 0.04), but not vs. IPAQ score (r = 0.17; p = 0.26). HIV infection may reduce spontaneous cBRS, which seemed to be moderated by higher BMI, but not PA level of PLHIV

Towards predicting liquid fuel physicochemical properties using molecular dynamics guided machine learning models

Accurate determination of fuel properties of complex mixtures over a wide range of pressure and temperature conditions is essential to utilizing alternative fuels. The present work aims to construct cheap-to-compute machine learning (ML) models to act as closure equations for predicting the physical properties of alternative fuels. Those models can be trained using the database from MD simulations and/or experimental measurements in a data-fusion-fidelity approach. Here, Gaussian Process (GP) and probabilistic generative models are adopted. GP is a popular non-parametric Bayesian approach to build surrogate models mainly due to its capacity to handle the aleatory and epistemic uncertainties. Generative models have shown the ability of deep neural networks employed with the same intent. In this work, ML analysis is focused on two particular properties, the fuel density and diffusion, but it can also be extended to other physicochemical properties. This study explores the versatility of the ML models to handle multi-fidelity data. The results show that ML models can predict accurately the fuel properties of a wide range of pressure and temperature conditions.The research leading to these results had received funding from the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP) through Programa de Recursos Humanos (PRH) under the PRH 8 - Mechanical Engineering for the Efficient Use of Biofuels, grant agreement numbers F0A5.EDDE.B5C0.3BCB and 2B61.4F5C.A83B.A713.Peer ReviewedPostprint (published version

Respostas hemodinâmicas durante exercício muscular inspiratório em jovens saudáveis

The literature on hemodynamic responses during inspiratory muscle exercise (IME) lacks a consensus. To evaluate and compare hemodynamic responses during an IME session with and without resistive load, 15 sedentary men were subjected to two randomized IME sessions: one with 40% of maximal inspiratory pressure (IME 40%) and another without a resistive load (Sham), both of which were performed for two minutes over eight sets with oneminute intervals. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), total peripheral resistance (TPR), stroke volume (SV), cardiac output (CO), and heart rate (HR) were measured by infrared digital photoplethysmography during five basal minutes and during the IME sessions. One-way ANOVA analysis of variance and the Student’s t test for paired data were used to analyze hemodynamic response and delta values between sessions, respectively. Effect size was evaluated by Cohen’s D. A 5% significance level was adopted. SBP responses (sham: ∆−1±2 vs. 40%: ∆−4±2mmHg, p=0.27), DBP (sham: ∆2±1 vs. 40%: ∆1±2mmHg, p=0.60) and MBP (sham: ∆2±1 vs. 40%: ∆0±2mmHg, p=0.28) were similar between sessions. HR increases were higher in the 40% IME session than in the sham session (sham: ∆9±2 vs. 40%: ∆3±2bpm, p=0.001). SV only decreased during the sham session but responses were similar between sessions (sham: ∆−2±2 vs. IME 40%: ∆−6±2ml, p=0.13). Both sessions did not change SBP, DBP, MBP, CO, and TPR, but we observed a greater increase in HR in the IME 40% session. Only the Sham session decreased SV.A literatura carece de um consenso sobre respostas hemodinâmicas durante o exercício muscular  inspiratório (EMI). Este estudo buscou avaliar e comparar as respostas hemodinâmicas durante uma sessão de EMI com e sem carga resistiva. Para tanto, 15 homens sedentários foram submetidos a duas sessõesrandomizadas de EMI: 40% da pressão inspiratória máxima (EMI 40%) e sem carga resistiva (sham), realizadas por dois minutos em oito séries e com intervalos de um minuto. A pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), pressão arterial média (PAM), resistência periférica total (RPT), volume sistólico (VS), débito cardíaco (DC) e frequência cardíaca (FC) foram medidos por fotopletismografia  infravermelha digital por cinco minutos basais e durante as sessões de EMI. Anova de um fator e o teste t de Student para dados pareados foram usados para analisar a resposta hemodinâmica e os valores delta entre as sessões, respectivamente. O tamanho do efeito foi avaliado pelo d de Cohen. Adotou-se nível de significância de 5%. As respostas de PAS (sham: ∆−1±2 vs. 40%: ∆−4±2mmHg, p=0,27), PAD (sham: ∆2±1 vs. 40%: ∆1±2mmHg, p=0,60) e PAM (sham: ∆2±1 vs. 40%:∆0±2mmHg, p=0,28) foram semelhantes entre as sessões. Os aumentos da FC foram maiores na sessão de EMI 40% do que nas sessões sham (sham: ∆9±2 vs. 40%: ∆3±2bpm, p=0,001). O VS diminuiu exclusivamente durante a sessão sham mas a resposta foi semelhante entre as sessões (sham: ∆−2±2 vs. EMI 40%: ∆−6±2ml, p=0,13). Ambas as sessões não causaram alteração nas variáveis PAS, PAD, PAM, DC e RPT, mas notamos um aumento maior da FC na sessão EMI 40%. Apenas a sessão sham reduziu o VS.No hay consenso en la literatura sobre las respuestas hemodinámicas durante el ejercicio muscular inspiratorio (EMI).El objetivo de este estudio fue evaluar y comparar las respuestas hemodinámicas durante una sesión de EMI con y sin carga resistiva. Para ello, quince hombres sedentarios recibieron dos sesiones aleatorias de EMI: el 40% de la presión inspiratoria máxima (EMI40%) y sin carga resistiva (sham), realizadas durante dos minutos, ocho sesiones y a intervalos de un minuto. La presión arterialsistólica (PAS), la presión arterial diastólica (PAD), la presión arterial media (PAM), la resistencia periférica total (RPT), el volumensistólico (VS), el gasto cardíaco (GC) y la frecuencia cardíaca (FC) se midieron mediante fotopletismografía infrarroja digital durantecinco minutos al inicio y durante las sesiones de EMI. Se utilizaron ANOVA unidireccional y la prueba t de Student a datos emparejadospara analizar la respuesta hemodinámica y los valores delta entre las sesiones. El tamaño del efecto se evaluó por el d de Cohen. Elnivel de significancia adoptado fue de 5%. Las respuestas de PAS (sham: Δ−1±2 vs. 40%: ∆−4±2mmHg, p=0,27), PAD (sham: ∆2±1 vs.40%: ∆1±2mmHg, p=0,60) y PAM (sham: ∆2±1 vs. 40%: ∆0±2mmHg,p=0,28) fueron similares entre las sesiones. El incremento de la FC fue mayor en la sesión de EMI 40% comparada con la sesión sham (sham: Δ9±2 vs. 40%: ∆3±2bpm, p=0,001). El VS tuvo una disminución exclusiva durante la sesión sham, pero la respuestafue similar entre las sesiones (sham: Δ−2±2 vs. EMI 40%: ∆−6±2ml, p=0,13). Ambas sesiones no tuvieron cambios en las variables PAS, PAD, PAM, DC y RPT, pero se observó un mayor incremento de la FC en la sesión EMI 40%. Solamente en la sesión sham hubo una reducción del V

Is the Weight of the Newborn Puppy Related to Its Thermal Balance?

Newborns experience a significant thermal change at birth, leading their bodies to adjust and reduce their metabolism to survive. In this study, newborn puppies’ weights and their temperatures in different body areas and at different measure times were evaluated to determine if there is a relationship between weight and their ability to reach thermostability. It was observed that there is a positive relationship between the weight of the puppies and their thermoregulatory capacity

Hemodynamic responses during inspiratory muscle exercise in healthy young adults

ABSTRACT The literature on hemodynamic responses during inspiratory muscle exercise (IME) lacks a consensus. To evaluate and compare hemodynamic responses during an IME session with and without resistive load, 15 sedentary men were subjected to two randomized IME sessions: one with 40% of maximal inspiratory pressure (IME 40%) and another without a resistive load (Sham), both of which were performed for two minutes over eight sessions with one-minute intervals. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), total peripheral resistance (TPR), stroke volume (SV), cardiac output (CO), and heart rate (HR) were measured by infrared digital photoplethysmography during five basal minutes and during the IME sessions. One-way analysis of variance and the Student’s t test for paired data were used to analyze hemodynamic response and delta values between sessions. Effect size was evaluated by Cohen’s D. A 5% significance level was adopted. SBP responses (sham: ∆−1±2 vs. 40%: ∆−4±2mmHg, p=0.27), DBP (sham: ∆2±1 vs. 40%: ∆1±2mmHg, p=0.60) and MBP (sham: ∆2±1 vs. 40%: ∆0±2mmHg, p=0.28) were similar between sessions. HR increases were higher in the 40% IME session than in the sham session (sham: ∆9±2 vs. 40%: ∆3±2bpm, p=0.001). SV only decreased during the sham session but responses were similar between sessions (sham: ∆−2±2 vs. IME 40%: ∆−6±2ml, p=0.13). Both sessions did not change SBP, DBP, MBP, CO, and TPR, but we observed a greater increase in HR in the IME 40% session. Only the Sham session decreased SV

Influência da hereditariedade para hipertensão arterial na hipotensão pós-exercício

Verificar o comportamento cardiovascular de homens normotensos com histórico familiar positivo para hipertensão arterial proveniente da mãe e de homens normotensos com histórico familiar proveniente do pai após uma sessão de exercício aeróbio. Foram selecionados 35 homens adultos divididos nos grupos: HF+mãe (somente mãe com hipertensão arterial, n=14) e HF+pai (somente pai com hipertensão arterial, n=21). Os participantes foram submetidos ao exercício aeróbio, em cicloergômetro (Kikos®), por 50 minutos, em intensidade de 50 a 70% da frequência cardíaca de reserva (sessão exercício) e a uma sessão controle. As variáveis pressão arterial média (FinometerPro®) e fluxo sanguíneo do antebraço (Pletismografia de Oclusão Venosa-Hokanson®) foram registradas continuamente durante 10 minutos pré e 30 minutos pós cada sessão. A resistência vascular do antebraço foi calculada pela divisão da pressão arterial média pelo fluxo sanguíneo do antebraço. Foi considerado p≤0,05 como diferença significativa. No grupo HF+mãe a pressão arterial média e a resistência vascular do antebraço não modificaram significativamente no momento pós em relação ao momento pré-exercício. Diferentemente, no grupo HF+pai a pressão arterial média e resistência vascular do antebraço reduziram significativamente na recuperação do exercício. Na sessão controle essas variáveis aumentaram significativamente no pós em relação ao pré, em ambos os grupos. O exercício físico não provocou modificações no sistema cardiovascular de homens normotensos, com histórico familiar positivo para hipertensão proveniente da mãe. Enquanto aqueles com histórico familiar positivo para hipertensão proveniente do pai apresentaram hipotensão pós-exercício, comportamento parcialmente justificado pela diminuição da resistência vascular do antebraço.To verify the cardiovascular response of normotensive men with positive family history of arterial hypertension from the mother and of normotensive men with positive family history of arterial hypertension from the father after an aerobic exercise session. Were selected 35 adult men divided into groups: HF+mother (only mother with arterial hypertension, n = 14) and HF+father (only father with arterial hypertension, n = 21). The participants underwent aerobic exercise, on a cycle ergometer (Kikos®), for 50 minutes, at intensity of 50 to 70% of the reserve heart rate (exercise session) and a control session. The variables mean arterial pressure (FinometerPro®) and forearm blood flow (Venous Occlusion Plethysmography-Hokanson®) were continuously recorded for 10 minutes before and 30 minutes after each session. The forearm vascular resistance was calculated by dividing the mean arterial pressure by the forearm blood flow. Was considered significant p≤0.05. In the HF+mother group, mean arterial pressure and forearm vascular resistance did not change significantly in the post-moment compared to the pre-exercise moment. In contrast, in the HF+father group, mean arterial pressure and forearm vascular resistance significantly reduced in recovery from exercise. In the control session, these variables increased significantly in the post compared to the pre, in both groups. Physical exercise did not cause changes in the cardiovascular system of normotensive men, with a positive family history of hypertension from the mother. While those with a positive family history of hypertension from their father presented post-exercise hypotension, behavior partially justified by the decrease in vascular resistance in the forearm