bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting road flooding risk with crowdsourced reports and fine-grained traffic data
Authors: Yuan Faxi , Lee Cheng-Chun , Mobley William , Farahmand Hamed , Xu Yuanchang , Blessing Russell , Dong Shangjia , Mostafavi Ali , Brody Samuel D. 
Published: March 2023

AbstractThe objective of this study is to predict road flooding risks based on topographic, hydrologic, and temporal precipitation features using machine learning models. Existing road inundation studies either lack empirical data for model validations or focus mainly on road inundation exposure assessment based on flood maps. This study addresses this limitation by using crowdsourced and fine-grained traffic data as an indicator of road inundation, and topographic, hydrologic, and temporal precipitation features as predictor variables. Two tree-based machine learning models (random forest and AdaBoost) were then tested and trained for predicting road inundations in the contexts of 2017 Hurricane Harvey and 2019 Tropical Storm Imelda in Harris County, Texas. The findings from Hurricane Harvey indicate that precipitation is the most important feature for predicting road inundation susceptibility, and that topographic features are more critical than hydrologic features for predicting road inundations in both storm cases. The random forest and AdaBoost models had relatively high AUC scores (0.860 and 0.810 for Harvey respectively and 0.790 and 0.720 for Imelda respectively) with the random forest model performing better in both cases. The random forest model showed stable performance for Harvey, while varying significantly for Imelda. This study advances the emerging field of smart flood resilience in terms of predictive flood risk mapping at the road level. In particular, such models could help impacted communities and emergency management agencies develop better preparedness and response strategies with improved situational awareness of road inundation likelihood as an extreme weather event unfolds.
Overview of the potential use of fluvoxamine for COVID-19 and long COVID
Authors: Hashimoto Kenji 
Published: March 2023

AbstractCoronavirus disease 2019 (COVID-19) has presented a serious worldwide threat to public health since its emergence in late 2019. From a safety point of view, drug repurposing has received particular attention. Several clinical studies have demonstrated that the use of fluvoxamine, a selective serotonin reuptake inhibitor with potent sigma-1 receptor agonism, in the early-stage of infection might be associated with the prevention of clinical deterioration in individuals with SARS-CoV-2 infection, although several reports have shown that a low dose of fluvoxamine may be ineffective. There is increasing evidence that SARS-CoV-2 can cross the blood–brain barrier, resulting in a number of psychiatric and neurologic symptoms in COVID-19 survivors. Importantly, about half of COVID-19 survivors experience a variety of long-term sequelae, including psychiatric and neurologic symptoms, known as long COVID. In this priority review, the author presents an overview of the potential use of fluvoxamine in the treatment of COVID-19 and long COVID.
Changes in Poison Center Calls for Intentional Exposure During Public Health Emergencies: COVID-19 and Winter Storm Uri in Dallas County, Texas
Authors: Fischer Shira H. , Landis Rachel K. , Acosta Joie D. , Faherty Laura J. 
Published: March 2023

Abstract

Objective:
This study aimed to: (1) explore changes in the volume of calls to poison control centers (PCs) for intentional exposures (IEs) in Dallas County, Texas, overall and by gender and age, and (2) examine the association between 2 different public health emergencies (PHEs) and changes in IE call volume.

Methods:
PCs categorize calls they receive by intentionality of the exposure, based on information from the caller. We analyzed data on PC calls categorized as intentional in Dallas County, Texas, from March 2019 – April 2021. This period includes the COVID-19 pandemic declaration (March 2020), a surge in COVID-19 cases (July 2020), and Winter Storm Uri (February 2021). Changes in IE call volume (overall and by age and gender), were explored, and interrupted time series analysis was used to examine call volume changes after PHE onset.

Results:
The summer surge in COVID-19 cases was associated with 1.9 additional IE calls/day (95% CI 0.7 to 3.1), in the context of a baseline unadjusted mean of 6.2 calls per day (unadjusted) before November 3, 2020. Neither the pandemic declaration nor Winter Storm Uri was significantly associated with changes in call volume. Women, on average, made 1.2 more calls per day compared to men during the study period. IE calls for youth increased after the pandemic declaration, closing the longstanding gap between adults and youth by early 2021.

Conclusions:
Changes in IE call volume in Dallas County varied by gender and age. Calls increased during the local COVID-19 surge. Population-level behavioral health may be associated with local crisis severity.
Approximate and discrete Euclidean vector bundles
Authors: Scoccola Luis , Perea Jose A. 
Published: March 2023

Abstract
We introduce

$\varepsilon $

-approximate versions of the notion of a Euclidean vector bundle for

$\varepsilon \geq 0$

, which recover the classical notion of a Euclidean vector bundle when

$\varepsilon = 0$

. In particular, we study Čech cochains with coefficients in the orthogonal group that satisfy an approximate cocycle condition. We show that

$\varepsilon $

-approximate vector bundles can be used to represent classical vector bundles when

$\varepsilon> 0$

is sufficiently small. We also introduce distances between approximate vector bundles and use them to prove that sufficiently similar approximate vector bundles represent the same classical vector bundle. This gives a way of specifying vector bundles over finite simplicial complexes using a finite amount of data and also allows for some tolerance to noise when working with vector bundles in an applied setting. As an example, we prove a reconstruction theorem for vector bundles from finite samples. We give algorithms for the effective computation of low-dimensional characteristic classes of vector bundles directly from discrete and approximate representations and illustrate the usage of these algorithms with computational examples.
Collimated gamma beams with high peak flux driven by laser-accelerated electrons
Authors: Fan Lulin , Xu Tongjun , Li Shun , Xu Zhangli , Xu Jiancai , Zhu Jianqiang , Shen Baifei , Ji Liangliang 
Published: March 2023

Abstract
Laser-accelerated electrons are promising in producing gamma-photon beams of high peak flux for the study of nuclear photonics, obtaining copious positrons and exploring photon–photon interaction in vacuum. We report on the experimental generation of brilliant gamma-ray beams with not only high photon yield but also low divergence, based on picosecond laser-accelerated electrons. The 120 J 1 ps laser pulse drives self-modulated wakefield acceleration in a high-density gas jet and generates tens-of-MeV electrons with 26 nC and divergence as small as

$1.51{}^{\circ}$

. These collimated electrons produce gamma-ray photons through bremsstrahlung radiation when transversing a high-Z solid target. We design a high-energy-resolution Compton-scattering spectrometer and find that a total photon number of

$2.2\times {10}^9$

is captured within an acceptance angle of

$1.1{}^{\circ}$

for photon energies up to

$16\;\mathrm{MeV}$

. Comparison between the experimental results and Monte Carlo simulations illustrates that the photon beam inherits the small divergence from electrons, corresponding to a total photon number of

$2.2\times {10}^{11}$

and a divergence of

$7.73{}^{\circ}$

.
Asymptotic persistence time formulae for multitype birth–death processes
Authors: Ball Frank G , Clancy Damian 
Published: March 2023

AbstractWe consider a class of processes describing a population consisting of k types of individuals. The process is almost surely absorbed at the origin within finite time, and we study the expected time taken for such extinction to occur. We derive simple and precise asymptotic estimates for this expected persistence time, starting either from a single individual or from a quasi-equilibrium state, in the limit as a system size parameter N tends to infinity. Our process need not be a Markov process on
$ {\mathbb Z}_+^k$
; we allow the possibility that individuals’ lifetimes may follow more general distributions than the exponential distribution.
Mapping Literature with Networks: An Application to Redistricting
Authors: Lo Adeline , Judge-Lord Devin , Hudson Kyler , Mayer Kenneth R. 
Published: March 2023

AbstractUnderstanding the gaps and connections across existing theories and findings is a perennial challenge in scientific research. Systematically reviewing scholarship is especially challenging for researchers who may lack domain expertise, including junior scholars or those exploring new substantive territory. Conversely, senior scholars may rely on long-standing assumptions and social networks that exclude new research. In both cases, ad hoc literature reviews hinder accumulation of knowledge. Scholars are rarely systematic in selecting relevant prior work or then identifying patterns across their sample. To encourage systematic, replicable, and transparent methods for assessing literature, we propose an accessible network-based framework for reviewing scholarship. In our method, we consider a literature as a network of recurring concepts (nodes) and theorized relationships among them (edges). Network statistics and visualization allow researchers to see patterns and offer reproducible characterizations of assertions about the major themes in existing literature. Critically, our approach is systematic and powerful but also low cost; it requires researchers to enter relationships they observe in prior studies into a simple spreadsheet—a task accessible to new and experienced researchers alike. Our open-source R package enables researchers to leverage powerful network analysis while minimizing software-specific knowledge. We demonstrate this approach by reviewing redistricting literature.
Fleet planning models
Authors: Trevett J.C. 
Published: March 2023

Fleet planning is a complex process. Undertaking it is time consuming as, properly conducted, it involves virtually every part of the airline organisation in a series of sub-analyses all of which impact on each other in some way. Parts of the process are deeply technical but others may be purely subjective relying on the intuition or judgement of the airline’s one expert in the particular field.Obviously in fleet planning we have to investigate suitable types of aircraft. Most of the factors involved are fairly well known. Their ability, or otherwise, to operate our routes economically and without significant restriction is vitally important as is our ability to maintain them in service. We need to understand our markets and the factors which influence passengers to travel in the first place, and with us rather than our competitors in the second.
The application of dynamic cold neutron fluoroscopy for the visualisation of fuel and oil system operating characteristics in gas turbine development
Authors: Stewart P. A. E. 
Published: March 2023

SummaryThis paper describes the first work undertaken to see the flows of oil, kerosene, water or any other hydrogenous fluid within a steel casing. In the specific case described, the performance and movement of the oil in the scavenge system of the Rolls-Royce Gem helicopter gas turbine was clearly seen with the engine operating at a range of test conditions.The work was conducted using cold neutrons from the DIDO nuclear reactor at AERE, Harwell, England, and this was the first time that such work has been attempted. The experiment was a complete success and provided answers to developmental problems in the oil system.In the paper, the preliminary work on the ‘Herald’ reactor at AWRE, Aldermaston, leading to this breakthrough in technology is also described.
Operation of new aircraft
Authors: Ratcliffe G. B. 
Published: March 2023

What is the record of the airlines over the past two decades? Is it a performance of which we can be proud? Have accidents occurred that could have been avoided? Are we becoming complacent? What may be the consequences of the present airline economic situation with regard to airworthiness? Are our staff adequately trained and will they continue to be so?These are just a few of the questions we must keep asking ourselves if we are to improve our airworthiness and safety records.
Deflections of inflated cylindrical cantilever beams subjected to bending and torsion
Authors: Webber J. P. H. 
Published: March 2023

In the aeronautical field, there has been from time to time an interest in inflatable structures, ranging from their consideration for use in space to the design and manufacture of an inflatable wing for a man-powered aircraft and their use in remotely piloted vehicles . This interest stems from the fact that such structures have relatively low weight; are suitable for reacting light loads and can be packed into a small volume.One particularly useful structural component is the inflated circular cylinder acting as a cantilever and a number of such cylinders are used in Ref. 3 to form the main load carrying structure of a wing. In Ref. 1 an expression is derived for the collapse load of a single cylinder with the assumption that the root behaves like a plastic hinge, and in Ref. 5, Comer and Levy go on to consider the beam deflections and stresses between incipient wrinkling and final collapse.
The regeneration of the turboprop
Authors: Coplin John F. 
Published: March 2023

In 1945, the world's first turboprop-powered aircraft took off. It was a converted Gloster Meteor fighter aircraft, powered by two turbopropeller derivative engines based upon the Derwent 2 jet engine (Figs. 1 and 2).By 1953 the world's first turbopropeller-powered airliner entered service. It was the Vickers Viscount powered by four Rolls-Royce Dart engines (Figs. 3 and 4).To date, 7125 Darts have been sold and by the end of 1982 they had accumulated more than 100 million hours in service. The case for the turboprop as a powerplant for the commuter aircraft continues as strong as ever it was, but the Dart must be replaced by a low cost more fuel-efficient engine. Rolls-Royce plans for this are outlined.With the present emphasis on fuel efficiency, a case is emerging for a 90-100-seat twin turboprop-powered super commuter — a market which Rolls-Royce intends to enter. Current estimates for a service date for such an aircraft place it in the region of 1992 to 1995.
The solution of large flutter problems on small computers
Authors: Simpson A. 
Published: March 2023

SummaryThe ‘inverse method’ proposed in 1936 by Duncan, Collar and Lyon for the calculation of flutter boundaries is re-stated in a form suited to modern methods of dynamical and numerical analysis and programmed for use on a home computer. The method is extended to provide information on sub- and supercritical eigenvalues. For a microcomputer with 32K RAM, flutter problems of orders up to 35 may be accurately solved.
Some thoughts on mathematical models for flight dynamics
Authors: Thomas H. H. B. M. 
Published: March 2023

SummaryThe objective of the present paper is to examine how the mathematical modelling of the overall aircraft system, in order to calculate its flight dynamics, has had to change to meet the requirements set by the type of problem posed. Some of these requirements reflect an increasing complexity in the aerodynamic design of the aeroplane. Others, a desire to improve the accuracy of the solutions to new and sometimes old problems.In addition the basic difficulties raised by the fact that, strictly speaking, the aerodynamic forces and moments depend on the past as well as the present history of the motion.A comparison is made of the aerodynamic formulations constructed from the character of the dynamics with those deduced, on the basis of a number of assumptions, from an analysis, which starts by considering the true nature of the aerodynamic forces and moments. In mathematical terms this is expressed by describing them as functionals of all the state variables.
Evaporation from freely falling droplets
Authors: Spillman J. J. 
Published: March 2023

SummaryAn analysis of results from reports on droplet evaporation indicated a marked difference in behaviour depending upon the suspension technique used. Few results were obtained with freely falling droplets, the condition which is of interest in aerial spraying operations. Test results obtained at Cranfield by dropping droplets down a climatic tower showed two unexpected results.The diameter of water droplets reduced linearly with time until they reached a size of about 150 micrometers and then the rate of reduction in diameter increased by about 27%. It is shown that this change occurs when the fall Reynolds number of the droplet becomes less than about 4.Above this Reynolds number the airflow is separated from the base of the droplet and the trapped air in the toroidal vortex becomes fully saturated and no evaporation occurs over the base region. Below a Reynolds number of 4 the flow is attached everywhere and evaporation occurs from the whole surface area.When small amounts of molasses are added to a spray formulation the droplets evaporated initially in a way similar to water droplets. As a result of falling, a toroidal vortex motion is induced within the droplet. This causes the same small fraction of the volume of the droplet to cycle close to the surface.Hence, this fraction of the volume looses all its water, becomes far more viscous as a result and the consequence is the toroidal motion almost stops. In effect the molasses forms a skin over the droplet surface inhibiting further evaporation of the remaining volume of water.
The thick turbulent boundary layer on a long fine cylinder in axial flow
Authors: Luxton R. E. , Bull M. K. , Rajagopalan S. 
Published: March 2023

SummaryTransverse curvature effects in axi-symmetric flow on a circulai cylinder are discussed and it is deduced that for small δ/a, where δ is the boundary layer thickness and a is the cylinder radius, transverse curvature effects are small, for δ/a = 0(1) the effect is felt mainly in the outer region and for δ/a » 1, both the inner and the outer regions are affected. It is argued that the last case can only be achieved experimentally in the laboratory if the radius Reynolds number Ra= U1a/v is small and the streamwise Reynolds number Rx=U1xlv is large, implying x/a large. New experimental data are presented for this case. The data show that both the mean and turbulent flow field scale on outer variables throughout the layer and, for Ra≥455, exhibit Reynolds number independence. No logarithmic region is found in the mean profiles, a result which is echoed by the absence of a shoulder in the streamwise turbulence profiles which clearly evidence that the flow in the layer is fully turbulent. A flow model is suggested, in physical terms, to explain the very high turbulence levels found close to the cylinder at values of Ra which should, according to stability theory, be bordering on laminar flow.
The flows over tapered flat plates normal to the stream
Authors: Gaster M. , Ponsford P. J. 
Published: March 2023

Experimental measurements of the separated flows around a range of tapered flat plates normal to a uniform stream are presented. Both the surface pressures and velocities in the wake are discussed. It turns out that even slight taper can modify the wake region of the flow significantly, and so produce a surprising degree of three-dimensionality into the overall flow structure. These experimental results point to the dangers in applying simple strip theories to highly separated flows.Aerodynamic theory has evolved over the years to describe the flow fields around streamlined aircraft and their components, so as to provide, amongst other quantities, accurate estimates of the aerodynamic forces and moments.
Helicopter ground resonance — a spatial model analysis
Authors: Nahas M. N. 
Published: March 2023

AbstractClassic theory of helicopter ground resonance studies the phenomenon on a planar model obtained by reducing the dynamic parameters of the full helicopter into the plane of rotation. In this paper the phenomenon is studied on a spatial helicopter model of six degrees of body freedom. It is found that in general there exist six regions of instability, whereas the planar theory of Coleman determines only one region. The theoretical results obtained here are verified by experiments conducted on a dynamic model of helicopter. In addition, this paper reviews all the existing analyses which have studied the problem.
Cross-flow and vorticity patterns in the corner boundary layer at different corner angles
Authors: Wilkinson S. R. , Zamir M. 
Published: March 2023

SummaryBoundary layer equations are derived for viscous high-Reynolds number flow along streamwise concave corners using a simple non-orthogonal Cartesian co-ordinate system. The equations are solved numerically for corner angles of 30°, 60°, 90°, 120° and 150°, with emphasis given to the cross-flow velocity and streamwise vorticity fields. The results are discussed in the context of the inherent instability of this boundary layer at high Reynolds numbers.
The effect of superimposed Rankine and forced vortices on conical diffuser performance
Authors: Neve R. S. , Thakker A. 
Published: March 2023

It is not always possible for a designer to accommodate a conical diffuser giving the greatest possible pressure recovery for a given area ratio because this usually involves a long version with a total conical angle of about 7 degrees. Considerable efforts have therefore been made to improve the performance of diffusers with total conical angles up to at least 30 degrees by adopting various techniques listed in Ref. 1. One suggestion was the addition of whirl to the flow in the inlet pipe; that is, to superimpose a vortex coaxial with the pipe and diffuser axis. However, Refs. 1 and 2 show the amount of published research on this topic to have been meagre.A previous paper has dealt with the case of adding a forced vortex whirl velocity distribution to the incoming flow and showed that improvements were possible, certainly in static pressure recovery and even in so-called efficiency, using a restricted definition of the latter. Because of mechanical vibration problems, the maximum swirl angle that could be added to the flow was about 15 degrees, corresponding to a forced vortex rotation rate of about 28 rad/s. This led to a beneficial redistribution of axial velocity components and a diminished tendency for flow separation from the walls.
The Darrieus wind turbine for electrical power generation
Authors: Robinson M. L. 
Published: March 2023

Wind energy has long been recognised as a potentially abundant source of clean and renewable mechanical and electrical power. History records that wind energy has been harnessed by man since about the year 2000 BC when windmills were used for energy production in Babylon and China. An ancient Persian vertical-axis windmill of about 7th century vintage is shown in Fig. 1. Windmills appeared in Europe in the 12th century and flourished until the 19th century as one of the few forms of rotary mechanical power. The Dutch windmill achieved lasting fame as the subject of paintings and etchings by the Dutch Masters including Rembrandt and van Ruisdael. Rembrandt's etching ‘The Windmill’ shows the fine detail of a 17th century windmill in Amsterdam.The final versions of Dutch and English windmills were relatively sophisticated machines, well suited to the tasks of grinding grain and other materials, pumping water and sawing wood. Steam power came to displace wind power in the 18th century, and windmill numbers diminished rapidly during the late 19th and early 20th centuries. Nevertheless, working examples of traditional windmills can still be seen in Holland, England and on the Greek islands.