To meet the development needs of aeroengines for high thrust-to-weight ratios and fuel-air ratios, a high temperature rise triple-swirler main combustor was designed with a total fuel-air ratio of 0.037, utilising advanced technologies including staged combustion, multi-point injection and multi-inclined hole cooling. Fluent software was used to conduct numerical simulations under both takeoff and idle conditions, thereby obtaining the distribution characteristics of the velocity and temperature fields within the combustor, as well as the generation of pollutants. The simulation results indicate that under takeoff conditions, the high temperature rise triple-swirler combustor achieves a total pressure loss coefficient of less than 6% and a combustion efficiency exceeding 99%. Under takeoff conditions, the OTDF and RTDF values are 0.144 and 0.0738, respectively. The mole fraction of NOx emissions is 3,700ppm, while the mole fraction of soot emissions is 2.55×10−5ppm. Under idle conditions, the triple-swirler combustor maintains a total pressure loss coefficient of less than 6% and a combustion efficiency greater than 99.9%. The OTDF and RTDF values are 0.131 and 0.0624, respectively. The mole fractions of CO and UHC emissions are both 0×10−32ppm at the calculation limit of Fluent software.

The formation of siderite and magnetite by Fe(III)-reducing bacteria may play an important role in C and Fe geochemistry in subsurface and ocean sediments. The objective of this study was to identify environmental factors that control the formation of siderite (FeCO3) and magnetite (Fe3O4) by Fe(III)-reducing bacteria. Psychrotolerant (<20°C), mesophilic (20–35°C) and thermophilic (>45°C) Fe(III)-reducing bacteria were used to examine the reduction of a poorly crystalline iron oxide, akaganeite (β-FeOOH), without a soluble electron shuttle, anthraquinone disulfuonate (AQDS), in the presence of N2, N2-CO2(80:20, V:V), H2 and H2-CO2 (80:20, V:V) headspace gases as well as in -buffered medium (30–210 mM) under a N2 atmosphere. Iron biomineralization was also examined under different growth conditions such as salinity, pH, incubation time, incubation temperature and electron donors. Magnetite formation was dominant under a N2 and a H2 atmosphere. Siderite formation was dominant under a H2-CO2 atmosphere. A mixture of magnetite and siderite was formed in the presence of a N2-CO2 headspace. Akaganeite was reduced and transformed to siderite and magnetite in a -buffered medium (>120 mM) with lactate as an electron donor in the presence of a N2 atmosphere. Biogeochemical and environmental factors controlling the phases of the secondary mineral suite include medium pH, salinity, electron donors, atmospheric composition and incubation time. These results indicate that microbial Fe(III) reduction may play an important role in Fe and C biogeochemistry as well as C sequestration in natural environments.

Coupling of clearance joint and harsh aerodynamic heating environment is an inevitable nonlinear factor in folding mechanism of the fin of high-speed aircrafts that remarkably modifies natural frequencies and modes of vibration from the initial design state. However, accurately predicting dynamic properties of deployable fin with full consideration of these effects is not common industry practice. A practical semi-analytical model based on Hertz contact theory and ESDU-78035 model is proposed in this study to investigate high-temperature connection stiffness of local hinged–locked mechanisms. Material property degradation and clearance variation caused by thermal expansion are comprehensively considered and quantified in this model. Vibration characteristics of the assembled deployable fin are then solved using finite element method (FEM). The real-time evolutionary process of thermal mode of the fin is discussed. And natural frequencies of fixed-value and time-varying connection stiffness are compared. The simulation results of this study demonstrate that the relative error of structure temperature between the sequential approach and fully coupled simulations is less than 6.98%. The connection stiffness (slope of the load-displacement curve) of the folding mechanism under high temperature conditions decreases by 3.52%, and the variation is mainly caused by the degradation of the elastic modulus of the material, while the clearance change due to the thermal expansion has no significant effect on the slope. The natural frequency of the deployable fin exhibits an inverse correlation with the temperature change trend, and the first three frequencies decrease by 1.67, 7.75, and 16.28 Hz compared to the initial value, respectively.

This work proposes a machine-learning or artificial intelligence (AI) control of a low-drag Ahmed body with a rear slant angle φ = 35° with a view to finding strategies for efficient drag reduction (DR). The Reynolds number Re investigated is 1.7 × 105 based on the square root of the body cross-sectional area. The control system comprises of five independently operated arrays of steady microjets blowing along the edges of the rear window and vertical base, twenty-six pressure taps on the rear end of the body and a controller based on an ant colony algorithm for unsupervised learning of a near-optimal control law. The cost function is designed such that both DR and control power input are considered. The learning process of the AI control discovers forcing that produces a DR up to 18 %, corresponding to a drag coefficient reduction of 0.06, greatly exceeding any previously reported DR for this body. Furthermore, the discovered forcings may provide alternative solutions, i.e. a tremendously increased control efficiency given a small sacrifice in DR. Extensive flow measurements performed with and without control indicate significant alterations in the flow structure around the body, such as flow separation over the rear window, recirculation bubbles and C-pillar vortices, which are linked to the pressure rise on the window and base. The physical mechanism for DR is unveiled, along with a conceptual model for the altered flow structure under the optimum control or biggest DR. This mechanism is further compared with that under the highest control efficiency.

Racial differences in Clostridioides difficile infection (CDI) outcomes have been reported. In this study, minoritized patients with CDIs had prolonged hospitalizations and increased intensive care unit admissions. Chronic kidney disease was shown to partially mediate the relationship between race or ethnicity and severe CDI. Our findings suggest potential areas for equitable interventions.

Racially and ethnically minoritized (REM) patients are disproportionately affected by infectious diseases, including candidemia. REM patients with candidemia were significantly younger, with trends toward more risk factors for candidemia and longer lengths of stay. Although Candida parapsilosis was more common in REM patients, there were no differences in mortality rates.

The pulsed jet is a novel and effective active mixing enhancement approach. For the transverse pulsed jet in the supersonic crossflow, the frequency influence is investigated using the three-dimensional Reynolds-averaged Navier–Stokes (RANS) equations coupled with the SST k-ω turbulence model. The averaged flow field properties of the pulsed jet are better than those of the steady jet when considering mixing efficiency and jet penetration depth, especially for the case with the pulsed frequency being 50kHz. The flow field structures of the pulsed jet are connected with the time, with periodic wave structures generating in the flow field and moving downstream. The size of the wave structures and its distance are related to the frequency, namely the size and flow distance are relatively small at 50kHz, and it takes some time for the pulsed jet to establish its influence in the full flow field. At low frequencies, the flow field produces large fluctuations, and this may be detrimental to the stable operation of the engine.

Steinernema populi n. sp. was recovered by baiting from beneath poplar trees in China. Morphological and molecular features provided evidence for placing the new species into the Kushidai clade. The new species is characterized by the following morphological features: third-stage infective juveniles (IJ) with a body length of 1095 (973–1172) μm, a distance from the anterior end to excretory pore of 77 (70–86) μm and a tail length of 64 (55–72) μm. The Body length/Tail length (c) ratio and Anterior end to Excretory pore/ Tail length × 100 (E%) of S. populi n. sp. are substantially greater than those of all other ‘Feltiae–Kushidai–Monticolum’ group members. The first-generation males can be recognized by a spicule length of 66 (57–77) μm and a gubernaculum length of 46 (38–60) μm. The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that Steinernema akhursti and Steinernema kushidai are the closest relatives to S. populi n. sp.

This work aims to investigate experimentally the effect of the Reynolds number Re, based on the nozzle diameter D, on jet mixing manipulation using an unsteady radial minijet. A novel artificial intelligence (AI) control system has been developed to manipulate the jet over Re = 5800–40 000. The system may optimize simultaneously the control law and a time-independent parameter, which dictate the actuation ON/OFF states and amplitude, respectively. The control parameters include the mass flow rate, excitation frequency and diameter ratios (Cm, fe/f0 and d/D) of the minijet to the main jet as well as the duty cycle (α) of minijet injection. Jet mixing is quantified using Ke and K0, where K is the decay rate of the jet centreline mean velocity, and subscripts e and 0 denote the manipulated and unforced jets, respectively. It has been found that the maximum Ke achievable does not vary with Re. Scaling analysis of the huge volume of experimental data obtained from the AI system reveals that the relationship Ke = g1 (Cm, fe/f0, α, d/D, Re, K0) may be reduced to Ke/K0 = g2 $(\zeta )$, where g1 and g2 are different functions and the scaling factor $\zeta = ({C_m}/\alpha ){(D/d)^{1 - n}}(1/Re){({f_e}/{f_{e,opt}})^m}$, m and 1 − n are the power indices, and subscript opt denotes the value at which Ke is maximum. The scaling law is discussed in detail, along with the physical meanings of the dimensionless parameters Ke/K0, ζ, $({C_m}/\alpha ){(D/d)^{1 - n}}(1/Re)$ and ${({f_e}/{f_{e,opt}})^m}$.

OBJECTIVES/GOALS: Whole-genome viral sequencing is vital to inform public health and study evolution. Arboviruses evolve in vectors, reservoir hosts, and humans, and require surveillance at all points. We developed a new rigorous method of sequencing that captures whole viral genomes in field-collected and clinical samples. METHODS/STUDY POPULATION: ClickSeq is a novel method of Next Generation Sequencing (NGS) library synthesis using azido-nucleotides to terminate reverse transcription. The cDNA generated can be ligated to sequencing and indexing primers at room temperature using copper (Cu I) and vitamin C. With this approach, we designed primers located ~250 bp apart along the genomes of the arboviruses Chikungunya 37797, Zika Dakar, Yellow Fever Asibi, Dengue serotype 2, West Nile 385-99, and St. Louis Encephalitis Virus (SLEV) clade II. We tested this method with varying viral titers: lab-infected mosquito pools, field-collected mosquito pools from a Texas West Nile and SLEV outbreak, and patient isolates from a Pakistani CHIKV outbreak. The cDNA was sequenced in the UTMB NGS Core and aligned using bowtie. RESULTS/ANTICIPATED RESULTS: The use of a single protocol to capture whole viral genomes including UTRs for multiple viruses from different sample collection styles is ideal for arboviruses. Primers for multiple viruses were pooled and used to sequence mosquito pools. The Tiled ClickSeq method captured whole viral genomes without the need for host depletion. UTRs were captured even when the viral strain used for primer design differed from the resulting strain. Discreet variants were captured in both the hypervariable nsP3 region and the UTR in the patient isolates from the CHIKV outbreak compared to the 2017 outbreak. Texas WNV and SLEV outbreaks are now defined from the 2020 outbreak and can be further tracked to update public health measures and understand viral evolution. DISCUSSION/SIGNIFICANCE: UTRs impact both human and mosquito fitness, leading to further outbreaks. Tiled ClickSeq aims to capture whole viral genomes with a method and cost that can be implemented by public health researchers to understand disease evolution as it happens to update both public health and basic virology to the effects of evolution on arboviruses.

Livestock plays a crucial role in food and nutrition security. However, livestock production accounts for 0.18 of global greenhouse gas emissions. India has one of the highest livestock densities globally, mainly produced under traditional systems. Specifically, the emission and particularly nitrogen losses from cattle in traditional systems cannot be ignored. Nitrogen emission is substantial when cattle roam free and waste is not collected or managed efficiently. This paper reviews the literature to piece together the available information on nitrogen emissions from cattle in India to synthesize the evidence, identify gaps and contribute to further understanding of the problem. At the same time, the paper highlights the solutions to reduce nitrogen pollution from cattle production in India. The main findings are that most cattle in India are not reared to provide meat protein. The implication is that reactive nitrogen per capita consumption is lower than most developed countries. However, there are substantial inefficiencies in feed conversion, feed nitrogen use and manure management in India. As a result, nitrogen losses and wastage are considerable in the different production systems. Furthermore, the review suggests that social, cultural and economic factors such as convergent social behaviour, urbanization, regulations, changing consumption patterns, the demand for cheap fuel sources, culture and religion influence the production systems and, consequently, the emissions from livestock. Suggested solutions to reduce nitrogen pollution from cattle production in India are improving livestock productivity, adopting better feeding, manure and pasture management practices and using behavioural nudges.