A computational study of preferential diffusion and scalar transport in nonpremixed hydrogen-air flame

The nonpremixed hydrogen-air reacting flow is simulated using three-dimensional direct numerical simulation coupled with flamelet generated manifolds based on detailed chemical kinetics. From the comparisons between one computational case taking into account preferential diffusion and another case with unity Lewis number assumption, the instantaneous results show that the flow is more vortical in the absence of preferential diffusion. This indicates that preferential diffusion may smooth the flame under certain circumstances when coupled with the intrinsic hydrodynamic instability. The flame compositional structures are also influenced by preferential diffusion in a significant manner. Further, the statistical information suggests that turbulent scalar flux is affected by preferential diffusion. The phenomenon of counter-gradient diffusion of both the conserved and non-conserved scalars can be detected for the two cases. The gradient model for scalar closure is found to be incapable of accurately predicting the scalar transport in nonpremixed hydrogen flames

A comparative study of instabilities in forced reacting plumes of nonpremixed flames

A comparative study has been performed to investigate the flow instabilities and their interaction for nonpremixed methane-air flames using experimental results, numerical simulations and theoretical analyses. The effects of buoyancy and the strong external perturbations on the vortex dynamics and instabilities of forced reacting plumes are studied. Results suggest that the flame surface breaks in forced reacting plumes and two flame fronts are formed eventually due to the convective instability coupled with buoyancy-driven instability. Flame pinch-off could occur in a short time for the cases with the strong perturbations of low frequencies. This indicates that the nonpremixed flame system exhibits a low-pass characteristic, which is sensitive to the low frequency perturbations. In addition, the buoyancy instability can be observed from the comparisons, which is of an absolute unstable nature. Despite the fact that theoretical analyses are derived from the single transport equation for mixture fraction with a number of assumptions, the results are still in good agreement with those obtained from the experiments and numerical simulations

AutoGen: Enabling Next-Gen LLM Applications via Multi-Agent Conversation Framework

This technical report presents AutoGen, a new framework that enables development of LLM applications using multiple agents that can converse with each other to solve tasks. AutoGen agents are customizable, conversable, and seamlessly allow human participation. They can operate in various modes that employ combinations of LLMs, human inputs, and tools. AutoGen's design offers multiple advantages: a) it gracefully navigates the strong but imperfect generation and reasoning abilities of these LLMs; b) it leverages human understanding and intelligence, while providing valuable automation through conversations between agents; c) it simplifies and unifies the implementation of complex LLM workflows as automated agent chats. We provide many diverse examples of how developers can easily use AutoGen to effectively solve tasks or build applications, ranging from coding, mathematics, operations research, entertainment, online decision-making, question answering, etc.Comment: 28 page

Weight self-misperception and Obesity-related Knowledge, Attitudes, Lifestyle Behaviors and Cardio-metabolic Markers among Chinese School-aged Children and Adolescents

Abstract Objective: The relationships between childhood weight self-misperception and obesity-related factors particularly health markers have not been extensively discussed. This study aims to examine the associations between weight self-misperception and obesity-related knowledge, attitudes, lifestyles and cardio-metabolic markers among Chinese pediatric population. Design: Cross-sectional study. Setting: Data sourced from a national survey in Chinese seven provinces in 2013. Participants: Children and adolescents aged 5-19 years. Results: Of the total 14079 participants, there were 14.5% and 2.2% participants over-estimated and under-perceived their weight, respectively. Multi-variable logistic regression was applied to calculate odds ratio (OR) and 95% confidence interval (95% Cl) of obesity-related behaviors and cardio-metabolic markers by actual and perceived weight status. Individuals who perceived themselves as overweight/obese were more likely to have prolonged screen time, insufficient dairy intake, and over sugar-sweetened beverages consumption (all P<0.05), regardless of their weight. Furthermore, actual overweight/obese individuals had higher odds of abnormal cardio-metabolic markers, but a smaller magnitude of association was found among weight under-estimators. Among non-overweight/obese individuals, weight over-estimation was positively associated with abdominal obesity (OR: 10.49, 95% CI: 7.45, 14.76), elevated blood pressure (OR: 1.30, 95% CI: 1.12, 1.51), and dyslipidemia (OR: 1.43, 95% CI: 1.29, 1.58). Conclusions: Weight over-perception was more prevalent than under-estimation, particularly in girls. Weight over-estimators tended to master better knowledge but behave more unhealthily, both weight over-perception and actual overweight/obesity status were associated with poorer cardio-metabolic markers. Future obesity intervention programs should additionally pay attention to the population with inaccurate estimation of weight who were easily overlooked

Noise Reduction of MEMS Gyroscope Based on Direct Modeling for an Angular Rate Signal

In this paper, a novel approach for processing the outputs signal of the microelectromechanical systems (MEMS) gyroscopes was presented to reduce the bias drift and noise. The principle for the noise reduction was presented, and an optimal Kalman filter (KF) was designed by a steady-state filter gain obtained from the analysis of KF observability. In particular, the true angular rate signal was directly modeled to obtain an optimal estimate and make a self-compensation for the gyroscope without needing other sensor’s information, whether in static or dynamic condition. A linear fit equation that describes the relationship between the KF bandwidth and modeling parameter of true angular rate was derived from the analysis of KF frequency response. The test results indicated that the MEMS gyroscope having an ARW noise of 4.87°/h0.5 and a bias instability of 44.41°/h were reduced to 0.4°/h0.5 and 4.13°/h by the KF under a given bandwidth (10 Hz), respectively. The 1σ estimated error was reduced from 1.9°/s to 0.14°/s and 1.7°/s to 0.5°/s in the constant rate test and swing rate test, respectively. It also showed that the filtered angular rate signal could well reflect the dynamic characteristic of the input rate signal in dynamic conditions. The presented algorithm is proved to be effective at improving the measurement precision of the MEMS gyroscope

Growth, Oxidative Stress and Ability to Degrade Tetrabromobisphenol A of <i>Phanerochaete</i> <i>chrysosporium</i> in the Presence of Different Nano Iron Oxides

In order to improve the performance of white rot fungi, especially the model species Phanerochaete chrysosporium in tetrabromobisphenol A (TBBPA) degradation, the strategy of synergizing Phanerochaete chrysosporium with nano iron oxides was considered; however, the effects of different nano iron oxides on Phanerochaete chrysosporium are still unknown. In this study, 20 nm γ-Fe2O3, 30 nm α-Fe2O3, 20 nm Fe3O4, and 200 nm Fe3O4 were used, and the fungal growth, oxidative stress, and ability to degrade TBBPA were monitored. The results showed that the addition of four nano iron oxides did not inhibit the growth of Phanerochaete chrysosporium. The effective antioxidant defense system of Phanerochaete chrysosporium could cope with almost all oxidative pressure induced by 200 nm Fe3O4. But when the size of nano iron oxide became significantly smaller or when the type of iron oxide changed from Fe3O4 to Fe2O3, a higher intracellular hydrogen peroxide (H2O2) content, lower intracellular superoxide dismutase (SOD) and catalase (CAT) activities and higher extracellular lactate dehydrogenase (LDH) activity were induced. When nano iron oxides synergized with Phanerochaete chrysosporium, the removal of TBBPA in all groups was slightly improved and mostly due to the degradation of TBBPA, with smaller iron oxides showing more enhancement for the degradation of TBBPA, while 200 nm Fe3O4 only enhanced the adsorption of TBBPA. The enhanced degradation of TBBPA showed no significant correlation with lignin-degrading enzyme activities but was closely correlated with the intracellular H2O2 concentration

Influence on therapeutic outcome of platelet count at diagnosis in patients with de novo non-APL acute myeloid leukemia

Abstract Background Platelet (PLT) count at diagnosis plays an important role in cancer development and progression in solid tumors. However, it remains controversial whether PLT count at diagnosis influences therapeutic outcome in patients with non-acute promyelocytic leukemia (APL) acute myeloid leukemia (AML). Methods This study analyzed the relationship between PLT count at diagnosis and genetic mutations in a cohort of 330 newly diagnosed non-APL AML patients. The impact of PLT count on complete remission, minimal residual disease status and relapse-free survival (RFS) were evaluated after chemotherapy or allogeneic hematopoietic stem cell transplantation (allo-HSCT). Results Our studies showed that patients with DNMT3A mutations have a higher PLT count at diagnosis, while patients with CEBPA biallelic mutations or t(8;21)(q22; q22) translocation had lower PLT count at diagnosis. Furthermore, non-APL AML patients with high platelet count (> 65 × 109/L) at diagnosis had worse response to induction chemotherapy and RFS than those with low PLT count. In addition, allo-HSCT could not absolutely attenuated the negative impact of high PLT count on the survival of non-APL AML patients. Conclusion PLT count at diagnosis has a predictive value for therapeutic outcome for non-APL AML patients

Memories of a Girl Between Worlds: Speculative Common Worldings

This article combines collective biography, diffractive analysis, and speculative fabulation to weave together the authors’ childhood memories of “common worlding.” Our collective biography brings into focus how we engaged in common worlding in our childhoods through dreaming, metamorphosis, and play by tactfully moving across different worlds and learning with the human and more-than-human others we encountered. As we foreground childhood memory and its potential to reimagine pasts, presents, and futures, we explore what kind of conditions are necessary to (re)attune ourselves to the multiple worlds around us in order to maintain and nurture children’s—and our own—other-worldly connections