bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Flow Physics During the Transition of a Variable Pitch Fan From Nominal Operation to Reverse Thrust Mode
Authors: Vitlaris Dimitrios , Rajendran David John , Tunstall Richard , Whurr John , Pachidis Vassilios 
Published: October 2023

Abstract
The flow field during the transition of variable pitch fans (VPFs) from nominal operation to reverse thrust mode at typical “Approach Idle” engine power setting and aircraft touchdown speed of 140 knots is described in this work. An integrated airframe-engine-VPF research model that features a future 40,000 lbf geared high bypass ratio engine installed on a twin-engine airframe in landing configuration is used to explore the flow field in a fully transient unsteady Reynolds-averaged Navier–Stokes (URANS) simulation with imposed wall motion. A novel methodology that implements an adaptation of a mesh displacement equation to mimic the fan blade airfoil rotation is developed. The implementation of this method with gradual, small-step deformation along with an automated mesh update routine enables a high quality, near “real-time” simulation of the complete transition. The flow field during transition is characterized by the evolution from full typical forward flow through the engine to the development of massive recirculation regions at the feather pitch setting and finally to development of a reverse flow from the bypass nozzle to the fan passages. In the paper, the transient development of the various flow features through different stations of the engine flow path apropos the fan blade airfoil rotation to reverse thrust mode are discussed in detail. Also, the temporal development of the mass flow ingested through the engine, airframe decelerating force, and distorted flow at the core engine inlet are described. A hitherto unresolved fan power peaking during the middle of the transition and higher power requirement at reverse thrust mode is captured. The effect of fan rotational speed in terms of engine power setting and the aircraft touchdown velocity on the transition flow physics is explored. A comparison of this fully transient approach with discrete steady-state runs for different stagger angle settings is presented. The flow physics during transition to reverse thrust mode as described in this study is critical in understanding the feasibility of using VPF for reverse thrust in future aircraft. The new capability to study the transition in a fully transient simulation can be used as a design development aid to define design and control characteristics of the reverse thrust VPF.
A Comprehensive Study on Characterization of Residual Stress of Build-Up Layer and Prediction of Chip Warpage
Authors: Cai Chongyang , Wang Huayan , Yang Junbo , Yin Pengcheng , Park S. B 
Published: October 2023

Abstract
Better understanding and control of residual stress in the chip build-up layer are becoming more and more important for the assembly process. To estimate the chip warpage and characterize the residual stress, different methods are proposed. However, most of them have high cost or some limitations for the upper build-up material. In this study, an innovative method is proposed to characterize the residual stress and predict the chip warpage behavior of different size chips at different temperatures. The method combines experimental inspection of chip warpage and finite element analysis. By reducing the silicon die thickness, the influence of residual stress in the build-up layer can be amplified. The residual stress can be obtained by inspecting the increased warpage when the silicon dies are reduced to different thicknesses. Correlating the thermal increase warpages of thinner chips can help characterize the effective modulus and coefficient of thermal expansion (CTE) of the build-up layer. This study can help better understand the commonly classified build-up layer information. The results show good agreements between two types of samples under the same upstream process flow.
A Novel Axial Energy-Imparting Turbomachine for High-Enthalpy Gas Heating: Robustness of the Aerodynamic Design
Authors: Karefyllidis Nikolas , Rubini Dylan , Rosic Budimir , Xu Liping , Purola Veli-Matti 
Published: October 2023

Abstract
Hard-to-abate industrial processes, such as petrochemicals and cement production, have long been considered technically challenging to decarbonize. In response to the urgent demand to eliminate industrial CO2 emissions, a new class of energy-imparting turbomachines has been developed. These devices aim to convert mechanical into internal energy instead of pressurizing the gas, which enables high-temperature gas heating (up to 1700 ∘C) for a variety of applications. This article is organized into three parts. First, this article aims to demonstrate the capabilities of the novel, high-capacity, customizable, repeating-stage axial turbo-heater architecture for a hydrocarbon cracking example application. The study presents the new design requirements and working principles of this energy-imparting concept. The radically different objectives compared to a compressor enable ultra-high loading stage designs by avoiding the stability and efficiency constraints imposed on compressors. Within this new design space, the turbo-heater is able to achieve a loading coefficient ψ ≥ 4.0. Second, detailed numerical simulations of a multistage axial turbo-reactor with various vaneless space lengths are conducted. This work conclusively demonstrates the robustness and flexibility of the aerodynamic design despite employing a uniform blade design. It is emphasized that the concept is tolerant to unsteady interstage turbulent disturbances, enabling nominal work input conditions to be achieved even for the most compact arrangements. Finally, having confirmed that the aerothermal restrictions on the vaneless space length can be removed, the designer is free to tailor the design to optimize the chemical reaction by (1) tailoring the residence time distribution to improve the yield and coking rate, (2) homogenizing reaction progress by mixing-out concentration gradients, and (3) adjusting the rotational speed to account for variations in the reaction dynamics for different feedstocks.
Effect of Deflector on the Combustion Characteristics of a Micro-Combustor With a Controlled Centrally Slotted Bluff Body
Authors: Srinivasa Raghavan K. A. , Srinivasa Rao S. , Raju V. R. K. 
Published: October 2023

Abstract
Flame tip-opening in a micro-combustor with a controlled centrally slotted bluff body adversely affects the combustion characteristics, leading to reduced average combustion efficiency and exhaust gas temperature. To minimize the adverse effects of the flame tip-opening, a deflector is introduced in the micro-combustor, downstream to the bluff body, and its effect on various combustion parameters is studied. The insertion of a deflector significantly increases the exhaust gas temperatures in the central region by establishing a secondary flame root. However, sudden changes in the flow direction caused by the insertion of deflector induce a sudden expansion-compression strain on the flame front, thereby slightly reducing the temperature of the flame zones on either side of the central region. A downstream shift in the position of the deflector marginally mitigates the adverse effects of sudden expansion-compression strain on the exhaust gas temperature, as they are induced within the secondary reaction flame zones. On the other hand, the downstream shift of the deflector negatively impacts the exhaust gas temperature in the central region due to the reduced length available for near-complete combustion downstream of the secondary flame root. In conclusion, the deflector positioned farther from the outlet is found to result in better overall combustion characteristics at higher controllable flow ratios.
An Investigation on the Steady and Unsteady Wake Flow Regimes and Aerodynamic Characteristics of the Trapezoidal Cylinders Using Immersed Boundary-Lattice Boltzmann Method
Authors: Bhunia Akash , Sikdar Prabir , Dash Sunil Manohar 
Published: October 2023

Abstract
In this study, the flow physics of the forward-facing (FF) and backward-facing (BF) trapezoidal cylinders (TC) subjected to two-dimensional, incompressible, and laminar flow is investigated using an in-house developed flexible forcing immersed boundary-lattice Boltzmann solver. The Reynolds number (Re) is defined based on the cylinder's characteristic length D. For the steady and unsteady flow regimes, Re is varied in the ranges of 10–40 and 75–125, respectively. The TCs shape is varied by modifying its nondimensional axial H/D and transverse Y/D length scales, between 0.5 to 2 and 0 to 1, respectively. Here, TCs horizontal central axis is always aligned along the incoming flow direction. It is observed that the flow separation points on the FF-TC and BF-TC are strongly influenced by the geometric (H/D and Y/D) and flow parameters (Re). Based on the boundary layer separation point, we have categorized the wake flow regimes behind the FF-TC and BF-TC into four types. In addition, the effect of the geometric and flow parameters on the drag coefficient (Cd), vortex shedding frequency, and steady and unsteady wake characteristics are thoroughly investigated here. Furthermore, by performing nonlinear regression analysis, we have proposed a set of correlation equations for the Cd and Strouhal number (St), using which the aerodynamic characteristics of differently shaped TC can be derived in the considered Re range without performing rigorous numerical simulations or experiments.
A Time Domain Model to Predict Dynamic Response of Multiple Floating Bodies Connected With Hinges Based on the Kane Method
Authors: Liu Junyi , Chen Xujun , Ji Song , Huang Heng , Chen Xi , Tu Qunzhang 
Published: October 2023

Abstract
A two-dimensional model to estimate the hydrodynamic response of hinged multiple floating body systems in the time domain is established based on the Kane method. The reduced Kane equations applicable to the dynamic response of multi-floating body system with hinges are first deduced. The issue of hinge constraint in the system is addressed by defining the corresponding generalized speeds as zeros, while the wave actions are considered based on the potential flow theory. Then the corresponding calculation program is developed prior to undertaking the model test. Verification of the Kane-based model and the veracity of the program developed is performed through a series of contrastive analyses on a hinged floating bridge in various cases including regular waves, moving loads, and their combinations. The predictions obtained by the proposed model show satisfactory agreements with the model test measurements. The related results indicate that the motion responses of the first pontoon are greatest in a hinged floating bridge, and its motion amplitudes descend nonlinearly with the increment of wave frequency. The time-history motion responses of hinged multi-floating bodies in the middle present saddle shapes with some fluctuations as a whole under the combined effect of wave and moving loads. The Kane-based model is convenient to analyze the dynamic characteristics of a hinged multi-floating body system in regular waves, and it could be further extended to consider the effects of irregular waves, inhomogeneous sea conditions, as well as the nonlinear connections on the system.
Metabolic versatility of soil microbial communities below the rocks of the hyperarid Dalangtan Playa
Authors: Liu Li , Chen Yan , Shen Jianxun , Pan Yongxin , Lin Wei 
Published: October 2023

ABSTRACT

Microbial assemblages inhabiting soils sheltered by rocks are widespread in the hyperarid and hypersaline Dalangtan Playa, which could contribute significantly to the ecological processes in this desert ecosystem. Here, we performed geochemical and metagenomic analyses of soils below and beside rocks in the Dalangtan Playa. Fourier transform infrared (FTIR) spectra show more evident signals of organic aromatic molecules in soils below rocks than in nearby bare soils. Soils below rocks harbor distinct microbial communities and much higher biomass and
Cyanobacteria
abundance in comparison to soils beside rocks. High-quality genomes recovered by hybrid short- and long-read assembly reveal the previously underappreciated contribution of
Actinobacteriota
in sheltered soils to the primary production of desert ecosystems. In contrast to bare soil communities, the metabolic versatility of sheltered soil communities indicates their critical roles in carbon, nitrogen, and sulfur cycling in the Dalangtan Playa. Trace gases (CO and H
2
) could be significant energy sources for the respiration and sometimes carbon fixation of both bare and sheltered soil microorganisms in nutrient-deprived environments. The presence of multiple stress response genes against DNA damage, oxidative stress, and osmotic stress, as well as pathways for the biosynthesis and uptake of compatible solutes in genomes across all samples, reveals their capacity for tolerating polyextreme conditions.

IMPORTANCE
The hyperarid Dalangtan Playa in the western Qaidam Basin, northwestern China, is a unique terrestrial analog of Mars. Despite the polyextreme environments of this area, habitats below translucent rocks capable of environmental buffering could serve as refuges for microbial life. In this study, the hybrid assembly of Illumina short reads and Nanopore long reads recovered high-quality and high-continuity genomes, allowing for high-accuracy analysis and a deeper understanding of extremophiles in the sheltered soils of the Dalangtan Playa. Our findings reveal self-supporting and metabolically versatile sheltered soil communities adapted to a hyperarid and hypersaline playa, which provides implications for the search for life signals on Mars.
Transcending the challenge of evolving resistance mechanisms in
Pseudomonas aeruginosa
through β-lactam-enhancer-mechanism-based cefepime/zidebactam
Authors: Hujer Andrea M. , Marshall Steven H. , Mack Andrew R. , Hujer Kristine M. , Bakthavatchalam Yamuna Devi , Umarkar Kushal , Palwe Snehal R. , Takalkar Swapna , Joshi Prashant R. , Shrivastava Rahul , Periasamy Hariharan , Bhagwat Sachin S. , Patel Mahesh V. , Veeraraghavan Balaji , Bonomo Robert A. 
Published: October 2023

ABSTRACT

Multi-drug resistant (MDR)
Pseudomonas aeruginosa
harbor a complex array of β-lactamases and non-enzymatic resistance mechanisms. In this study, the activity of a β-lactam/β-lactam-enhancer, cefepime/zidebactam, and novel β-lactam/β-lactamase inhibitor combinations was determined against an MDR phenotype-enriched, challenge panel of
P. aeruginosa
(
n
= 108). Isolates were multi-clonal as they belonged to at least 29 distinct sequence types (STs) and harbored metallo-β-lactamases, serine β-lactamases, penicillin binding protein (PBP) mutations, and other non-enzymatic resistance mechanisms. Ceftazidime/avibactam, ceftolozane/tazobactam, imipenem/relebactam, and cefepime/taniborbactam demonstrated MIC
90
s of >128 mg/L, while cefepime/zidebactam MIC
90
was 16 mg/L. In a neutropenic-murine lung infection model, a cefepime/zidebactam human epithelial-lining fluid-simulated regimen achieved or exceeded a translational end point of 1−log
10
kill for the isolates with elevated cefepime/zidebactam MICs (16–32 mg/L), harboring VIM-2 or KPC-2 and alterations in PBP2 and PBP3. In the same model, to assess the impact of zidebactam on the pharmacodynamic (PD) requirement of cefepime, dose-fractionation studies were undertaken employing cefepime-susceptible
P. aeruginosa
isolates. Administered alone, cefepime required 47%–68%
f
T >MIC for stasis to ~1 log
10
kill effect, while cefepime in the presence of zidebactam required just 8%–16% for >2 log
10
kill effect, thus, providing the pharmacokinetic/PD basis for in vivo efficacy of cefepime/zidebactam against isolates with MICs up to 32 mg/L. Unlike β-lactam/β-lactamase inhibitors, β-lactam enhancer mechanism-based cefepime/zidebactam shows a potential to transcend the challenge of ever-evolving resistance mechanisms by targeting multiple PBPs and overcoming diverse β-lactamases including carbapenemases in
P. aeruginosa
.

IMPORTANCE

Compared to other genera of Gram-negative pathogens,
Pseudomonas
is adept in acquiring complex non-enzymatic and enzymatic resistance mechanisms thus remaining a challenge to even novel antibiotics including recently developed β-lactam and β-lactamase inhibitor combinations. This study shows that the novel β-lactam enhancer approach enables cefepime/zidebactam to overcome both non-enzymatic and enzymatic resistance mechanisms associated with a challenging panel of
P. aeruginosa
. This study highlights that the β-lactam enhancer mechanism is a promising alternative to the conventional β-lactam/β-lactamase inhibitor approach in combating ever-evolving MDR
P. aeruginosa
.
Diversity and evolution of an abundant ICE
clc
family of integrative and conjugative elements in
Pseudomonas aeruginosa
Authors: Benigno Valentina , Carraro Nicolas , Sarton-Lohéac Garance , Romano-Bertrand Sara , Blanc Dominique S. , van der Meer Jan Roelof 
Published: October 2023

ABSTRACT

Integrative and conjugative elements (ICEs) are widespread autonomous mobile DNA elements, containing the genes necessary for their excision, conjugative transfer, and insertion into a new host cell. ICEs can carry additional genes that are non-essential for their transfer but can confer adaptive phenotypes to the host. Our aim here was to better characterize the presence, distribution, and variation of ICEs related to the well-described ICE
clc
among
Pseudomonas aeruginosa
clinical isolates within a geographically restrained environment to understand the factors contributing to their evolution. We examined a total of 181
P
.
aeruginosa
genome sequences obtained from patient or hospital environment isolates, most of which were obtained from a single hospital during 20 years of sampling. More than 90% of the isolates carried one or more ICE
clc
-like elements, with different degrees of conservation to the known ICE
clc
lifestyle and transfer genes. ICE clones closely matched their host clonal phylogeny, but not exclusively, indicating that both clonal evolution and ICE horizontal transfer are occurring in the hospital environment. ICEs from this singular hospital environment were mainly associated to three clone types found worldwide, suggesting an enrichment of local clones. Variable gene regions among the clinical
P. aeruginosa
ICE
clc
-type elements were notably enriched for heavy metal resistance genes, toxin-anti-toxin systems, potential efflux systems and multidrug resistance proteins, a metalloprotease and for a variety of regulatory systems, but not for specific recognizable antibiotic-resistance cassettes. Clonal persistence suggests adaptive benefits of these functional categories, and micro-patterns of gene gain and loss indicate ongoing ICE evolution within the
P. aeruginosa
hosts.

IMPORTANCE

Microbial populations swiftly adapt to changing environments through horizontal gene transfer. While the mechanisms of gene transfer are well known, the impact of environmental conditions on the selection of transferred gene functions remains less clear. We investigated ICEs, specifically the ICE
clc
-type, in
Pseudomonas aeruginosa
clinical isolates. Our findings revealed co-evolution between ICEs and their hosts, with ICE transfers occurring within strains. Gene functions carried by ICEs are positively selected, including potential virulence factors and heavy metal resistance. Comparison to publicly available
P. aeruginosa
genomes unveiled widespread antibiotic-resistance determinants within ICE
clc
clades. Thus, the ubiquitous ICE
clc
family significantly contributes to
P. aeruginosa
’s adaptation and fitness in diverse environments.
Subduction initiation recorded in the Dadeville Complex of Alabama and Georgia, southeastern United States
Authors: Becker Naomi A. , George Freya R. , Guice George L. , Crowley James L. , Nelson Wendy R. , Browning-Hanson Joseph F. , Roy Supratik , Viete Daniel R. 
Published: October 2023

AbstractThe Dadeville Complex of Alabama and Georgia (southeastern United States) represents the largest suite of exposed mafic-ultramafic rocks in the southern Appalachians. Due to poor preservation, chemical alteration, and tectonic reworking, a specific tectonic origin for the Dadeville Complex has been difficult to deduce. We obtained new whole-rock and mineral geochemistry coupled with zircon U-Pb geochronology to investigate the magmatic and metamorphic processes recorded by the Dadeville Complex, as well as the timing of these processes. Our data reveal an up-stratigraphic evolution in the geochemistry of the volcanic rocks, from forearc basalts to boninites. Our new U-Pb zircon crystallization data—obtained from three amphibolite samples—place the timing of forearc/protoarc volcanism no later than ca. 467 Ma. New thermobarometry suggests that the Dadeville Complex rocks subsequently experienced deep, high-grade metamorphism, at pressure-temperature conditions of &gt;7 kbar and &gt;760 °C. The data presented here support a model for formation of the Dadeville Complex in the forearc region of a subduction zone during subduction initiation and protoarc development, followed by deep burial/underthrusting of the complex during orogenesis.
Tool to assess risk of bias in studies estimating the prevalence of mental health disorders (RoB-PrevMH)
Authors: Tonia Thomy , Buitrago-Garcia Diana , Peter Natalie Luise , Mesa-Vieira Cristina , Li Tianjing , Furukawa Toshi A , Cipriani Andrea , Leucht Stefan , Low Nicola , Salanti Georgia 
Published: October 2023

ObjectiveThere is no standard tool for assessing risk of bias (RoB) in prevalence studies. For the purposes of a living systematic review during the COVID-19 pandemic, we developed a tool to evaluate RoB in studies measuring the prevalence of mental health disorders (RoB-PrevMH) and tested inter-rater reliability.MethodsWe decided on items and signalling questions to include in RoB-PrevMH through iterative discussions. We tested the reliability of assessments by different users with two sets of prevalence studies. The first set included a random sample of 50 studies from our living systematic review. The second set included 33 studies from a systematic review of the prevalence of post-traumatic stress disorders, major depression and generalised anxiety disorder. We assessed the inter-rater agreement by calculating the proportion of agreement and Kappa statistic for each item.ResultsRoB-PrevMH consists of three items that address selection bias and information bias. Introductory and signalling questions guide the application of the tool to the review question. The inter-rater agreement for the three items was 83%, 90% and 93%. The weighted kappa scores were 0.63 (95% CI 0.54 to 0.73), 0.71 (95% CI 0.67 to 0.85) and 0.32 (95% CI −0.04 to 0.63), respectively.ConclusionsRoB-PrevMH is a brief, user-friendly and adaptable tool for assessing RoB in studies on prevalence of mental health disorders. Initial results for inter-rater agreement were fair to substantial. The tool’s validity, reliability and applicability should be assessed in future projects.