bluuebunny/crossref_metadata_2025 huggingface dataset:
The 2021 Activity of the Fast-radio-burst-emitting Galactic Magnetar SGR 1935+2154 as Observed by NASA’s Fermi Gamma-Ray Burst Monitor
Authors: Rehan Noor ul Sabah , Ibrahim Alaa I.
Published: June 2023

The galactic, fast-radio-burst-emitting magnetar SGR 1935+2154 entered an active X-ray burst episode in 2021 September, nearly a year after emitting a fast radio burst with an X-ray counterpart. We report on the temporal and spectral properties of the activity, which included bright intermediate flares, and present a burst catalog of the Fermi Gamma-Ray Burst Monitor observations. We compare this activity to the previous 6 yr history of the source since its discovery in 2014. The bursts show a mean log-Gaussian duration T
100 ∼ 77.34 ms, a cutoff power-law peak energy E
peak ∼ 26.62 keV, and a photon index ΓCPL ∼ 0.49, and blackbody soft and hard temperatures kT
BBs ∼ 5.23 keV and kT
BBh ∼ 9.24 keV, respectively. The burst fluence spans 3 orders of magnitude (10−8–10−5 erg cm−2) and follows

dN

/

dS
∝

S

−
0.93

. The anticorrelation between the blackbody temperature and the emission area is weaker in the hard component at

R

BBh

2

∝

kT

BBh

−
4.56

but is improved in the soft component at

R

BBs

2

∝

kT

BBs

−
1.63

, compared to previous activities, with an overall

R

BB

2

∝

kT

BB

−
3.82

correlation. The 2021 bursts have higher average and integrated fluence than the 2014–2020 episodes and are relatively shorter than the 2019–2020 activities yet comparable to the earlier episodes. During 2014–2021, the burst mean peak energy (E
peak) shows a slight softening and is generally softer than other magnetars. We discuss our results in terms of magnetar physics and emission mechanisms.
Horizonless Spacetimes As Seen by Present and Next-generation Event Horizon Telescope Arrays
Authors: Eichhorn Astrid , Gold Roman , Held Aaron
Published: June 2023

We study the capabilities of present and future radio very long baseline interferometry arrays to distinguish black holes from horizonless spacetimes. We consider an example of a horizonless spacetime, obtained by overspinning a regular black hole. Its image is distinct from the image of a Kerr spacetime due to a second set of photon rings interior to the shadow. These photon rings cannot be directly resolved by present and even next-generation Event Horizon Telescope arrays, but instead imprint themselves in horizon-scale images as excess central brightness relative to that of a black hole. We demonstrate that future arrays can decrease the upper bound on the central brightness depression by a factor of 10 and thereby detect such indirect imprints from non-Kerr spacetimes in reconstructed images.
Limits on Leptonic TeV Emission from the Cygnus Cocoon with Swift-XRT
Authors: Guevel David , Beardmore Andrew , Page Kim L. , Lien Amy , Fang Ke , Tibaldo Luigi , Casanova Sabrina , Huentemeyer Petra
Published: June 2023

γ-ray observations of the Cygnus Cocoon, an extended source surrounding the Cygnus X star-forming region, suggest the presence of a cosmic-ray accelerator reaching energies up to a few PeV. The very-high-energy (VHE; 0.1–100 TeV) γ-ray emission may be explained by the interaction of cosmic-ray hadrons with matter inside the Cocoon, but an origin of inverse Compton radiation by relativistic electrons cannot be ruled out. Inverse Compton γ-rays at VHE are accompanied by synchrotron radiation peaked in X-rays. Hence, X-ray observations may probe the electron population and magnetic field of the source. We observed 11 fields in or near the Cygnus Cocoon with the Neil Gehrels Swift Observatory’s X-Ray Telescope (Swift-XRT) totaling 110 ks. We fit the fields to a Galactic and extragalactic background model and performed a log-likelihood ratio test for an additional diffuse component. We found no significant additional emission and established upper limits in each field. By assuming that the X-ray intensity traces the TeV intensity and follows a

dN

/

dE
∝

E

−
2.5

spectrum, we obtained a 90% upper limit of F
X < 8.7 × 10−11 erg cm−2 s−1 or <5.2 × 10−11 erg cm−2 s−1 on the X-ray flux of the entire Cygnus Cocoon between 2 and 10 keV depending on the choice of hydrogen column density model for the absorption. The obtained upper limits suggest that no more than one-quarter of the γ-ray flux at 1 TeV is produced by inverse Compton scattering, when assuming an equipartition magnetic field of ∼20 μG.
Direct Evidence of Electron Acceleration at the Dipolarization Front
Authors: Wei Y. Y. , Huang S. Y. , Jiang K. , Yuan Z. G. , Xu S. B. , Zhang J. , Xiong Q. Y. , Wang Z. , Lin R. T. , Yu L. , Li Y. Y. , Wang C. M. , Song G. J.
Published: June 2023

The dramatic changes in the magnetic field at the dipolarization front (DF) provide a suitable environment for electron acceleration, which usually can cause the flux enhancement of energetic electrons behind the front. However, it is unknown whether energetic electrons observed at the DF are energized locally, and which mechanism accelerates the electrons at the DF is unclear. Our study performs a direct quantitative analysis to reveal the acceleration process of energetic electrons at the DF using the high-time-resolution data from NASA's Magnetospheric Multiscale mission. The fluxes of energetic electrons at 90° are enhanced at the front. Under adiabatic conditions, our quantitative analysis indicates that these electrons at the front could be locally accelerated to over 100 keV by betatron acceleration. Eventually, the electron temperature anisotropy formed via the betatron mechanism could provide the free energy to excite whistler waves at the DF. Our quantitative study provides, for the first time, strong direct evidence for the local electron acceleration at the DF.
Continuous vocational training in response to the challenge of industry 4.0: Required skills and business results
Authors: Aranda Jose Ramon , Campos Irene , Cosculluela Carolina , San Martin Jose , De Pablos Carmen
Published: June 2023

Purpose: To identify the technical skills which, linked to digitalization processes, are required to achieve different types of business results. Design/methodology/approach: The Delphi method was applied, through the opinions of a group of Spanish experts, to identify the importance of certain skills for the advancement of digitalization and the implementation of Industry 4.0. Findings: The results show that: 1) skills in Robotics, the Internet of Things, Networks and Artificial Intelligence are necessary to achieve results in the management of company technical areas; 2) commercial management needs skills in Intelligent Systems, Big Data, Cybersecurity, Distributed Technology and Contents; and 3) for the business challenges of sustainable development, the environment and energy efficiency, the most needed skills are in Big Data, Intelligent Systems and Artificial Intelligence.Originality/value: The results are useful, firstly, in providing firms with a training and selection tool for the development of I4.0 and, secondly, in offering training centers criteria for drawing up their training programs.
Prospects of green financing in democratic societies
Authors: Bennink Hans
Published: June 2023

Financing ecological and other grand global challenges is faced with intertwined issues at both the institutional side and the public side as elements of the tragedy of the quintuple horizons. These horizons are approached from a systemic perspective, with attention on the key players involved. Starting with (system) banks, their conservative attitude is explained in terms of the iron cage theory. Next, green challenges are pictured as 'very wicked' problems, varying in moral intensity. The conflicting roles of the public as citizens and as consumers are described in terms of Kohlberg's theory of cognitive moral development. Responsibilities for future generations are clarified by distinguishing the responsibility as accountability and the responsibility as virtue. Assignments for a green future are explored from the perspective of green financing with a focus on what should be expected from the public at large in multiparty democratic societies, keeping in mind that other societies are characterized by diverting economic and political dynamics, and hence, other modes of operating1.

1 See, for instance, for China: Macaire & Naef (2022) and Liu, Wang, Zhang & Zhang (2019).
Projective class ring of a restricted quantum group $ \overline{U}_{q}(\mathfrak{sl}^{*}_2) $
Authors: Ji Pengcheng , Chen Jialei , Gao Fengxia
Published: June 2023

In this paper, we compute the projective class ring of the new type restricted quantum group $ \overline{U}_{q}(\mathfrak{sl}^{*}_2) $. First, we describe the principal indecomposable projective $ \overline{U}_{q}(\mathfrak{sl}^{*}_2) $-modules and study their radicals, composition series, Cartan matrix of $ \overline{U}_{q}(\mathfrak{sl}^{*}_2) $ and so on. Then, we deconstruct the tensor products between two simple modules, two indecomposable projective modules and a simple module and an indecomposable projective module, into direct sum of some indecomposable representations. At last, we characterize the projective class ring by generators and relations explicitly.
Electroencephalography and mild cognitive impairment research: A scoping review and bibliometric analysis (ScoRBA)
Authors: Wijaya Adi , Setiawan Noor Akhmad , Ahmad Asma Hayati , Zakaria Rahimah , Othman Zahiruddin
Published: June 2023

Mild cognitive impairment (MCI) is often considered a precursor to Alzheimer's disease (AD) and early diagnosis may help improve treatment effectiveness. To identify accurate MCI biomarkers, researchers have utilized various neuroscience techniques, with electroencephalography (EEG) being a popular choice due to its low cost and better temporal resolution. In this scoping review, we analyzed 2310 peer-reviewed articles on EEG and MCI between 2012 and 2022 to track the research progress in this field. Our data analysis involved co-occurrence analysis using VOSviewer and a Patterns, Advances, Gaps, Evidence of Practice, and Research Recommendations (PAGER) framework. We found that event-related potentials (ERP), EEG, epilepsy, quantitative EEG (QEEG), and EEG-based machine learning were the primary research themes. The study showed that ERP/EEG, QEEG, and EEG-based machine learning frameworks provide high-accuracy detection of seizure and MCI. These findings identify the main research themes in EEG and MCI and suggest promising avenues for future research in this field.
Proceedings of the 39th Congress Italian Society of Histochemistry - 14-16 June 2023, Vulcano Island, Italy
Authors: Committee The Scientific
Published: June 2023

Proceedings of the 39th Congress of the Italian Society of Histochemistry (SII) - 14-16 June 2023, Hotel Therasia Resort, Vulcano Island, Italy
Quantitative inverse theorem for Gowers uniformity norms and in
Authors: Milićević Luka
Published: June 2023

We prove quantitative bounds for the inverse theorem for Gowers uniformity norms
$\mathsf {U}^5$
and
$\mathsf {U}^6$
in
$\mathbb {F}_2^n$
. The proof starts from an earlier partial result of Gowers and the author which reduces the inverse problem to a study of algebraic properties of certain multilinear forms. The bulk of the work in this paper is a study of the relationship between the natural actions of
$\operatorname {Sym}_4$
and
$\operatorname {Sym}_5$
on the space of multilinear forms and the partition rank, using an algebraic version of regularity method. Along the way, we give a positive answer to a conjecture of Tidor about approximately symmetric multilinear forms in five variables, which is known to be false in the case of four variables. Finally, we discuss the possible generalization of the argument for
$\mathsf {U}^k$
norms.
Experimental and Numerical Ice Accretion Shapes on a Pitot Probe Model
Authors: Forsyth Peter , Szilder Krzysztof
Published: June 2023

This paper presents experimental ice accretion measurements alongside numerical simulations, using the National Research Council Canada’s morphogenetic approach, on a pitot probe geometry at varying icing conditions. In previous publications, the morphogenetic approach for the numerical simulation of ice accretion has shown promise for pitot probe applications, potentially reducing the number of wind tunnel entries, and therefore cost, of the development cycle. An experimental campaign has been completed, providing ice shapes on a representative pitot probe model. Comparison of the experimental and numerical ice shapes indicate that the morphogenetic model is able to generate the complex ice shapes seen experimentally for real-world icing conditions on a fully 3D geometry, closely matching both ice features and total ice thicknesses.
Impingement Analysis on Nacelle Inlet, Multibody Airfoil, and Swept Tail Cases under SLD Conditions
Authors: Da Silva Guilherme , Pio Diogo , Rafael Caio , Villela Pedro , Rezende Sabrina , Teixeira Da Silva Jayme
Published: June 2023

This paper presents impingement analysis on a nacelle inlet, multibody airfoil, and swept tail under Supercooled Large Droplet (SLD) conditions in icing tunnels. Impingement and collection efficiency calculations are crucial for ice shape and protection analyses. The aerospace icing community selected three cases for simulation, focusing on SLD conditions, which require specific mathematical models for accurate representation. The present authors used a Reynolds-averaged Navier-Stokes computational fluid dynamics (CFD) tool to evaluate pressure coefficients and collection efficiency, comparing them with experimental data. CFD simulations incorporated fully turbulent flow using various turbulence models and Eulerian droplet transport, considering experimental droplet distribution. The results showed acceptable deviations despite SLD simulation challenges and experimental data problems. A secondary conclusion suggests simplifying a 27-bin distribution to a 10-bin distribution to take into account the cumulative mass curve. An accumulated mass index is proposed to compare different simulations. Importantly, the CFD accurately captures the impingement limits, enhancing its value for engineering purposes. This study demonstrates the suitability of the CFD method by showcasing its application to address aircraft certification challenges, emphasizing the importance of integrating engineering perspectives within CFD simulation results.
Experimental Investigation of UAS Rotors and Ice Protection Systems in Appendix C Icing Conditions
Authors: Kozomara David , Amon Jakob , Puffing Reinhard , Neubauer Thomas , Schweighart Simon , Diebald Stefan , Rapf Andreas , Moser Richard , Breitfuss Wolfgang
Published: June 2023

If an Unmanned Aerial Systems (UAS) encounters icing conditions during flight, those conditions might result in degraded aerodynamic performance of the overall UAS. If the UAS is not reacting appropriately, safety critical situations can quickly arise. Thereby, the rotors, respectively the propellers of the UAS are especially susceptible due to the increased airflow through their domain and the corresponding higher impingement rate of supercooled water droplets. In many cases, the UAS cannot be properly operated if the rotors are not fully functional, as they are a vital component. The FFG/BMK funded research and development project

“All-weather Drone” is investigating the icing phenomenon on UAS rotors for a 25 kg maximum take-off weight (MTOW) multirotor UAS and evaluating the feasibility of possible technical ice detection and anti-/de-icing solutions. This paper presents results from the investigation carried out at the Rail Tec Arsenal (RTA) icing wind tunnel (IWT) in Vienna, Austria, where UAS rotors were exposed to defined icing conditions based on EASA CS-25 Appendix C. The experimental tests featured various rotors which were exposed to icing conditions without any protective measures to better understand the influence of ice accretion on the aerodynamic performance. In addition, possible technical solutions in form of an electrothermal and chemical anti-/de-icing system, as well as an ice-repellent surface coating were investigated. During the tests, the performance (power, thrust, torque) of the UAS rotors was monitored. The final ice accretion was documented by 3D laser scanning and photographs. The objective of this work is to contribute to a better understanding of icing of UAS rotors, while also investigating solutions that might enable the safe operation of multirotor UAS in icing conditions in the future.
Ice Crystal Accretion Tool (ICAT) capabilities on heated NACA0012 Airfoil
Authors: Roychowdhury Somasree , Poornima Rajani , Bokade Vilas , Jebauer Steffen , Vanacore Paolo , Malik Yasir A.
Published: June 2023

The present paper showcases the predicting ability of an in-house 2D/ Quasi-3D steady state Ice Crystal Accretion Tool (ICAT) applicable for both heated and un-heated surfaces. The previously existing code for unheated surfaces, has been extended to heated scenarios with the inclusion of: 1) coupling with solid conduction model 2) inclusion of advanced models for crystal melting, water film modeling, sticking and erosion. The results obtained from ICAT are verified against the experimental results of heated NACA0012 airfoil, conducted in the icing wind tunnel of TU Braunschweig as part of MUSIC-haic project. ICAT predictions are found to be well in agreement with the ICI physics, which is proven with the various parameters addressed in this paper, such as tunnel temperature, ice crystal temperature, inlet melt ratio, heating power, etc.
Pitot Probe and Total Air Temperature (TAT) Probe Ice Crystal Icing Impact to Aircraft Operation and Methods to Improve Probe Performance
Authors: Sable Robert
Published: June 2023

Pitot probes and Total Air Temperature (TAT) probes are critical to aircraft performance. They are also susceptible to becoming overwhelmed and produce erroneous outputs when flying in icing conditions, especially in high altitude ice crystal situations. When the probes are overwhelmed with ice crystals, it can have significant impacts to aircraft operations. Through design and process iterations, Collins Aerospace (also known as Rosemount Aerospace™), has developed new Appendix D compliant pitot and TAT probes that are much more capable in high ice crystal content icing environments which greatly reduce the adverse risks to the aircraft and engine systems that depend on these probes.
Carbon Nanotube (CNT) Based Electrothermal Ice Protection System Flight Tests
Authors: Hein Brandon , Botura Galdemir , Hamman Matthew , Slane Casey
Published: June 2023

Innovative carbon nanotube (CNT) electrothermal heating technology for ice protection systems is one of the alternatives under development that shall contribute to more efficient and sustainable aircraft. CNT heater technology allows for more rapid heat up rates over legacy metallic electrothermal heaters that utilize resistance wires or metallic foils. This more rapid heat up rate can lead to more energy efficient electrothermal ice protection system designs and is being studied to determine how much the rapid heat up properties of CNT can lead to a minimization of residual ice build-up aft of the heated area. Due to the inherent redundancy of CNT material used, leads to a very robust and damage tolerant heating element. To mature this technology to prepare to implement CNT on an in-service aircraft platform, a multi-staged flight testing effort to prove out the technology on an actual aircraft and in a relevant environment is mandatory. Recently a major milestone was achieved after successful execution of a dry air flight test campaign at Embraer’s Gavião Peixoto unit in Brazil. The new CNT ice protection system solution was successfully installed on the vertical stabilizer and flight tested in Embraer’s fully functional Phenom 300 prototype. Collins’ CNT heater and ice protection controller were integrated into the prototype aircraft before executing over 10 hours of ground and “dry air” flight tests. Since this was a prototype aircraft, the CNT was not certified for this aircraft and was only used for technology development purposes. As part of the effort to prepare a CNT based electrothermal ice protection system, structural and thermal analyses were performed along with icing wind tunnel testing to verify the performance of this new technology. This paper summarizes the work performed for the dry air flight test, including some initial performance results of CNT technology, and provide a brief review of the following development steps which included a natural ice flight test.
Numerical Study of Iced Swept-Wing Performance Degradation using RANS
Authors: Ozcer Isik , Pueyo Alberto , Menter Florian , Hafid Sabrina , Yang Hong
Published: June 2023

This paper studies the level of confidence and applicability of CFD simulations using steady-state Reynolds-Averaged Navier-Stokes (RANS) in predicting aerodynamic performance losses on swept-wings due to contamination with ice accreted in-flight. The wing geometry selected for the study is the 65%-scale Common Research Model (CRM65) main wing, for which NASA Glenn Research Center’s Icing Research Tunnel has generated experimental ice shapes for the inboard, mid-span, and outboard sections. The reproductions at various levels of fidelity from detailed 3D scans of these ice shapes have been used in recent aerodynamic testing at the Office National d’Etudes et Recherches Aérospatiales (ONERA) and Wichita State University (WSU) wind tunnels. The ONERA tests were at higher Reynolds number range in the order of 10 million, while the WSU tests were in the order of 1 million. RANS CFD results for the lower-Reynolds 8.9% WSU model up to α = 10° were previously generated by University of Virginia and NASA Glenn Research Center using Ansys Fluent and k-ω SST on the clean and low-fidelity (smooth) iced wings. The current CFD study focuses on the high-fidelity ice shape, presenting RANS results for both low and high Reynolds numbers, for the full α sweep up to α = 25° for which there is experimental data on the iced wings. A straight-forward automatable CAD-to-solution workflow is established using surface curvature and proximity-based mesh sizing functions for grid generation. The simulations results include CL, CM, CD curves for both clean and iced wings, their comparison to the experimentally obtained counterparts, iced surface Cp distributions, and a detailed breakdown of the computational cost and user effort in generating these solutions.
Phase Doppler Interferometry for Efficient Cloud Drop Size Distribution, Number Density, and LWC Measurements
Authors: Bachalo William Don
Published: June 2023

Threats to aviation safety as a result of super-cooled large drops (SLD) has been addressed by the FAA rules change (14 CFR Part 25) with the additional icing certification requirement. SLD clouds often consist of bi-modal drop size spectra leading to significant problems in simulating and characterizing these conditions in situ and in icing wind tunnels. Legacy instrumentation for measuring drop size distributions and liquid water content are challenged under these conditions. The large size range measurement problem is addressed with the development of the Phase Doppler Interferometer, Flight Probe Dual-Range (PDI FPDR). The method is described in this report along with the measurement capabilities including the dynamic measurement range and overall working size range. The PDI instrument bases drop size measurements on the light wavelength as the measurement length scale. The light wavelength is a much more robust scale, especially as compared to the light scattering intensity. Methods for accurately characterizing the sample volume in situ based on measured drop velocity and transit time are reviewed, given the importance of this parameter for merging results and measuring LWC. Droplet coincidence in the sample volume can be problematic so this condition is treated with an innovative signal parsing approach. Measurement examples acquired in the NASA IRT are provided. Measurements of LWC showed good agreement with the Artium Particle Imaging (PI) instrument but diverged from the tunnel calibration results for larger MVD values.
Statistical Process Control and Analysis on the Water Content Measurements in NASA Glenn’s Icing Research Tunnel
Authors: Timko Emily , King-Steen Laura , Insana Eric
Published: June 2023

The Icing Research Tunnel at NASA Glenn follows the recommended practice for calibration outlined in SAE’s ARP5905. The calibration team has followed the schedule of a full calibration every five years with a check calibration done every six months following. The liquid water content of the IRT has maintained stability within the stated specifications of variation within +/- 10% of the curve fit equation generated from calibration data. Using past measurements and data trends, IRT characterization engineers wanted to develop methods for the ability to know when data were not within variation. Trends can be observed in the liquid water content measurement process by constructing statistical process control charts. This paper describes data processing procedures for the Multi-Element Sensor in the IRT, including collision efficiency corrections, canonical correlation analysis, process for rejection of data, and construction of control charts. Data are presented to display the control capability to meet defined liquid water content specifications of the IRT with the Multi-Element Sensor mounted in the center of the test section.
A New 1D2D Optical Array Particle Imaging Probe for Airborne and Ground Simulation Cloud Measurements
Authors: Lilie Lyle , Bouley Daniel , Sivo Chris , Esposito Biagio , Bansemer Aaron , Heller Romy , Strapp J. Walter
Published: June 2023

A new optical array imaging probe, called the 1D2D probe, has been developed by Science Engineering Associates, with features added to improve the real-time and post-analysis measurements of particle spectra, particularly in the Supercooled Large Droplet size range. The probe uses optical fibers and avalanche photodiodes to achieve a very high frequency response, and a Field-Programmable Gate Array that performs real-time particle rejection and processing of accepted particles with negligible inter-particle dead time. The probe records monochromatic two-dimensional images, while also recording the number of individual particle pixels at a second grey scale level. The probe implements flexible features to filter recording of highly out of focus particles to improve the accuracy of particle size determination, or to reject small particles to improve the statistics of measurements of larger particles. A real-time one-dimensional particle spectrum is computed similarly to the original generation of 1D optical array probes, which will be refined using the advanced features as practical experience is achieved. A technique is described that shows promise in providing such a real-time spectrum with sufficient liquid spectrum MVD accuracy for icing wind tunnel calibration. The probe is housed in a cylindrical canister compatible with existing optical array probes, but with substantial additional de-icing. It has been tested in the laboratory, and at two wind tunnels, and tests include some comparisons to another commercially available probe. Probe design and performance, and preliminary results and comparisons are described.
Development of a Test Rig for the Assessment of Remotely Piloted Aircraft Systems (RPAS) in Icing
Authors: Orchard David
Published: June 2023

As the everyday use of flying small to medium size Remotely Piloted Aircraft System (RPAS) continues to evolve, so does the need to fly them in icing environments. To investigate an RPAS’ ability to fly in these conditions, an outdoor test rig has been developed at the National Research Council Canada (NRC) in which a range of RPAS have been tested in icing environments. This rig has an available test area of 3.05 m × 3.05 m, and is 5.1 m high. An array of spray nozzles installed at the top of the test rig provides a cloud that, when operated at sub-zero temperatures, enables simulation of in-flight icing conditions. The spray cloud is calibrated to provide water concentration and drop size distributions consistent with Appendix C, freezing drizzle and freezing rain conditions. Six RPAS were tested and their performance under icing conditions has been monitored via video and, where available, data provided by the on-board acquisition system was downloaded to enable flight information such as motor power and positional stability to be examined. It is shown that above a certain LWC, the time at which the systems could sustain flight in icing plateaus and no further increase in water content results in a reduction in the operational envelope. It was also found that the operational limits of the RPAS were independent of the median volumetric diameter (MVD).
Numerical Heat Transfer Simulations for Laser-Scanned Ice Shapes
Authors: Feier Ioan
Published: June 2023

Ice accretions on aircraft flight surfaces can degrade lift, increase drag, and reduce controllability. Anti-icing systems can remove or prevent ice growth. To predict the ice shrinkage or accretion using models such as LEWICE, the convective heat transfer behavior at the ice surface must be quantified. The work here is focused on understanding the convective heat transfer for several laser-scanned ice shapes by using commercial computational fluid dynamics (CFD) heat transfer simulations. The leading edge ice shape from a NACA 0012 airfoil and its geometrically unwrapped simplification are studied. Limitations encountered with a semi-automated unstructured mesh generation tool are presented. Thin boundary layer mesh thicknesses (i.e. much thinner than the flow’s viscous or thermal boundary layers) are found to be necessary in order to capture the surface curvature features and preserve good mesh quality near the geometric surface. To better model a prior experiment, the unwrapped geometry uses a conjugate heat transfer model which includes a thickness to the unwrapped ice shape to allow the modeling of its internal conductive heat transfer. The unwrapped geometry CFD heat transfer results are compared to prior experimental results for an identical shape in a similar heat transfer setup. Also, heat transfer results for the original airfoil ice shape are presented for constant surface temperature, and compared to the unwrapped iced plate. The CFD results predict higher Stanton numbers for turbulent flows as compared to laminar flows, but overall underpredict the Stanton numbers when compared to experiments, particularly in the iced bumpy region. Additional work is needed to study alternative meshing strategies and various turbulence model settings. The results are useful for advancing the understanding of convective heat transfer from ice shapes and conductive heat transfer in ice layers.
3D Immersed Boundary Methods for the Calculations of Droplet Trajectories towards Icing Application
Authors: Elices Paz Pablo , Radenac Emmanuel , Péron Stéphanie , Blanchard Ghislain , Laurendeau Eric , Villedieu Philippe
Published: June 2023

The in-flight ice accretion simulations are typically performed using a quasi-steady formulation through a multi-step approach. As the ice grows, the geometry changes, and an adaptation of the fluid volume mesh used by the airflow and droplet-trajectory solver is required. Re-meshing or mesh deformation are generally employed to do that. The geometries formed are often complex ice shapes increasing the difficulty of the re-meshing process, especially in three-dimensional simulations. Consequently, difficulties are encountered when trying to automate the process. Contrary to the usual body-fitted mesh approach, the use of immersed boundary methods (IBMs) allows solving, or greatly reducing, this problem by removing the mesh update, facilitating the global automation of the simulation. In the following paper, an approach to perform the airflow and droplet trajectory calculations for three-dimensional simulations is presented. This framework utilizes only immersed boundary methods. In particular, two methods are presented. On the one hand, a ghost-cell Immersed Boundary approach has been developed to solve the aerodynamics. The Euler equations are solved at fluid points, whereas the solution is forced in the vicinity of the obstacle at some particular cells (IB target points), in order to mimic a slip boundary condition. Special attention has been given to the applied boundary conditions as well as to the location of these IB target points. In fact, instead of the most commonly used approaches where the IB target points are placed in the solid or in the fluid, the case where these IB target points lie astride the obstacle (namely “GC Surrounding” in the following), in the fluid and solid regions, is studied. On the other hand, to solve the droplet trajectory equations, the penalization method, already present in IGLOO2D (the 2D ice accretion suite developed at ONERA), has been expanded to the three-dimensional simulations. The two immersed boundary methods are compared and numerically tested on different cases. First, a mesh refinement study is performed for weakly compressible flow around a cylinder. In this case, the solution is compared with that obtained using a body-fitted simulation and it serves as a verification of the method. Next, the approach is used in two other different cases. The first case involves an iced GLC305 airfoil, which is characterized by its complex geometry, under compressible subsonic conditions. The second case is a three-dimensional simulation in which the presented approach is used to analyze the weakly compressible flow around a sphere.
Introduction of an Online Ice Accretion Database
Authors: Neubauer Thomas , Puffing Reinhard
Published: June 2023

In the course of the Horizon 2020 project ICE GENESIS of the European Union, an experimental database was developed to host documentation of icing experiments. The database serves as a source of information for numerical code development and validation as well as future test matrix design, IPS layout and development and wing design. Several legacy data icing cases have been included into the database, which are partly publicly available. Furthermore, the database will serve as the main platform for dissemination of public results of icing cases after and during the project ICE GENESIS. The database itself provides detailed information about the test configurations and the icing wind tunnel. More specifically, CAD data, ice protection system characteristics if applicable, installation in the test facility, instrumentation, test matrix, generated aero-icing conditions and test results are included. Within the ICE GENESIS project, the documentation of the resulting ice accretion is done by the application of 3D scanning systems, which allows detailed ice shape evaluation and validation of 3D numerical tools performances. The database covers a large set of representative configurations (2D and 3D wings, engine inlets, cylinders) and will complement worldwide existing databases.
Implementation of the DADI Method into the Droplet Equation for Efficient Aircraft Icing Simulation
Authors: Kim Younghyo , Hong Yoonpyo , Shon Soonho , Yee Kwanjung
Published: June 2023

Diagonalized alternating-direction implicit (DADI) method is implemented in the Eulerian hyperbolic droplet solver, ICEPAC, for efficient high-order accurate analysis of aircraft icing. Detailed techniques for implementing the DADI method considering hyperbolicity characteristics are discussed. For the Eulerian droplet equation system to be strictly hyperbolic, additional source terms regarding artificial droplet pressure are included. Validations of the present implicit solver are conducted using two- and three-dimensional steady benchmark tests: NACA0012 airfoil, NACA23012 airfoil, and a swept wing. Also, the oscillating airfoil SC2110 case was analyzed to verify the robustness and efficiency of the proposed solver. In addition, the computational cost of the current implicit solver is considerably lower than that of the explicit multi-stage solver.
Investigation of Water Impingement on Aero-Components by Lagrangian and Eulerian Approach
Authors: Görgülü İlhan , Özgen Serkan
Published: June 2023

Icing related problems on aero-components have been recognized since the beginning of modern aviation. Various icing incidents occurred due to severe degradation of aerodynamic performance, and engine rollbacks. As in-flight icing can occur over a broad range of atmospheric and flight conditions, design of effective ice protection mechanisms on aero-components is essential. Computational simulations are a significant part of designing these mechanisms, therefore accurate prediction of droplet collection efficiency and accreted ice shapes are vital. In the current study, continued efforts to improve a computational in-flight icing prediction tool are introduced together with obtained results. The emphasis in this study is on the recent improvements introduced to flow-field and droplet trajectory calculation modules. The flow-field predictions were previously managed by Hess-Smith panel method and this module is fortified with inclusion of an open-source Navier-Stokes code. Droplet trajectories were being computed with Lagrangian method and now a finite volume based Eulerian droplet trajectory tracking model with explicit scheme is also available. In order to evaluate the performance of these major updates, code validation results are presented on various aero-components including a clean MS(1)-0317 supercritical airfoil, a clean NACA23012 airfoil along with 3 simulated ice shapes mounted on, a multi-element airfoil, an axisymmetric engine inlet and an inertial particle separator. Results obtained by Eulerian model are compared with experimental data from open literature and existing Lagrangian method findings when applicable. Present study and the results show that developed approach has potential in terms of computational time, accuracy and suitability for complex aero-component analysis.
Development of the Atmospheric Icing Patch (AIP) under the SENS4ICE Programme
Authors: Roberts Ian , Gent Roger , Hatch Colin , Moser Richard
Published: June 2023

The European Union’s Horizon 2020 programme has funded the SENS4ICE (Sensors for Certifiable Hybrid Architectures for Safer Aviation in Icing Environment) international collaboration flagship programme. Under this programme a number of different organizations have developed ice detection technologies, specifically aimed at providing information to differentiate between ‘classical’ Appendix C icing conditions and the larger droplets found in Appendix O icing. As a partner within the SENS4ICE project, AeroTex UK has developed an ice detection concept called the Atmospheric Icing Patch (AIP). The sensor utilizes a network of iso-thermal sensors to detect icing and differentiate between small and large droplet icing conditions. This paper discusses the development of the sensor technology with a focus on the outcomes of the flight testing performed on the Embraer Phenom 300 platform during early 2023.

The work in the programme is built on previous studies performed by AeroTex UK into a probe-based sensor that operates using the same approach. The patch approach was finally adopted as it minimizes heat losses and therefore draws significantly less power than the equivalent probe system. It is better suited to the detection and differentiation of small and large droplet conditions through the application of an array of patches. The aircraft plays a key role in the sensor function as the fuselage is used to inertially separate the droplets allowing some patches to be located where only large droplets would impinge whilst others are in locations where droplets of all sizes impinge. The fuselage installation means that variability in sensor response with angle-of-attack and sideslip is negligible compared to a lifting surface installation.

The testing conducted by Embraer on the Phenom 300 successfully demonstrated the system capabilities through the detection of icing conditions and differentiation between small and large droplet distributions. The sensor system also demonstrated the ability to estimate the Liquid Water Content (LWC), but further work is required to improve this correlation.
An Exceptional Presentation of “Watermelon Stomach” in a 30- Year-Old Cirrhotic Male
Authors: Salpekar Radhika , Upadhya Keerthan , Prasad Shiva
Published: June 2023

Gastric antral vascular ectasia (GAVE) is an unusual cause of chronic upper gastrointestinal bleeding commonly described in elderly females, with  associated autoimmune diseases, and in cirrhotic males. The entity is characterized by angioectasia in the pyloric antrum, giving its classic streaky  “watermelon stripe” appearance. This report highlights the rare presentation of a 30-year-old male with liver cirrhosis, who presented with anemia and  fatigability. Diagnosis of GAVE was made using endoscopy, and trials of argon plasma coagulation were administered. Following this, an antrectomy was  performed since there was a further drop in hemoglobin. The patient made a full recovery with no subsequent dependence on blood transfusions. GAVE can be mistakenly underdiagnosed as a treatable cause of occult gastrointestinal bleeding. This report mandates caution on endoscopy for younger  patients with an upper gastrointestinal bleed while taking other more common causes of gastrointestinal bleeding (peptic ulcers, esophageal varices,  and non-steroidal anti-inflammatory drugs [NSAID]-induced gastritis) into account.
Methamphetamine (Mkpuru-Mmiri) prevalence in Southeastern Nigeria: Exploring peoples' perception of public flogging as a control measure
Authors: Nnanna Nwangwu Chukwunwike , Okpan Samuel Okpanocha , Roberts Anya Nkata , Nwosuji Emeka Patrick , Ayuk Clara Oben , Eze Ifeoma Louisa , Ngwu Leonard Ugwu , Ogbuke Uchenna Martha
Published: June 2023

This study investigated the peoples' perception of public flogging as a control measure for methamphetamine (Mkpuru-Mmiri) use among youth in Southeastern Nigeria. The study adopted mixed methods. The questionnaire comprised (12) items administered to a sample size of 1055 through the online mediated platform – Google Forms, while the qualitative data were collected from (12) participants via face-to-face interviews. The quantitative data were processed using SPSS version 20.0 and displayed in descriptive statistics. The hypothesis was tested using the Mann-Whitney U test. The NVivo 10 software was used to analyze the qualitative data thematically. The study revealed that the practice seems to have been accepted as a social control measure for drug misuse in Southeast Nigeria. In addition, the hypotheses stipulate that educational level influenced the acceptability of public flogging as a methamphetamine deterrent with human rights concerns. The study concludes that preventing methamphetamine misuse can be accomplished by creating job opportunities for young people and rehabilitating users.
Prevalence and Management Strategies of Perceived Intestinal Parasitic Infections by Households in Imo State Nigeria
Authors: Ihejirika Onyenonachi Charity , Nwaorgu Obioma Chebechi , Nguma Chinwe Jane , Kenechukwu-Dozie Queen Ogechi , Anyanwu Emilia Oluchi , Uwakwe Felicia E. , Egbom Ezinne Sylvia , Ihejirika Chinedu Emeka
Published: June 2023

Background: Intestinal parasitic infections (intestinal worms) are major public health problems, especially in developing countries. This study was  conducted to determine the prevalence and management strategy of intestinal parasitic infections (IPIs) employed by households.

Methodology: The study was carried out in Imo State, south-eastern Nigeria. Faecal samples from 1200 school children, aged 6-13 years were examined  using the Kato Katz method and formol-ether concentration techniques. A structured and pre-tested questionnaire was used to collect data. The level of significance was set at P< 0.05.

Results: The total prevalence of IPIs was 19.3%, which comprises eight parasites namely; Ascaris lumbricoides (3.4%), Trichuris trichiura (1.3%),  hookworm (1.8%), Strongyloides stercoralis (0.2%), Taenia spp (0.5%), Entamoeba histolytica (5.3%), Entamoeba coli (3.7%), and Giardia lamblia (4.2%).  There was high awareness of possible signs and symptoms of IPIs. Albendazole, Pyrantel pamoate and Mebendazole were the three most frequently  used drugs and intermittent deworming with them was effective against the intestinal worm. The impact of deworming on the prevalence of intestinal worms was higher among children dewormed every 4 months, compared with other groups. Self-medication was a major practice amongst the study population.  Households (33.9%) delayed up to 48 hours from the onset of symptoms before giving the child medical attention. The majority of households used plant  extracts as alternative medication.

Conclusion: The management approaches in the study area were good although they did not regard IPIs as a  serious public health problem for a growing child.
Adherence to Covid-19 prevention protocols among adults residing in Kitui Central Sub-County, Kitui County, Kenya
Authors: Ngui Faith , Josphat Gichure , Taratisio Ndwiga , Muoki Francis Matheka
Published: June 2023

INTRODUCTION

The COVID-19 pandemic wreaked worldwide havoc resulting in at least 6.9 million deaths. In Kenya, the government laid out behavioural and social mitigation strategies to control its spread. This study aimed to assess adherence to COVID-19 mitigation measures among adults residing in Kitui County, Kenya.

METHODOLOGY

A descriptive cross-sectional study was conducted among households in Kitui Central Sub-County, Kitui County, Kenya sampling 384 participants. Data was collected using a semi-structured questionnaire and observation checklist. Principal Component Analysis, Chi-square and multiple regression were used to assess associations and causation using SPSS version 25.

RESULTS

The response rate was 85%. Almost all (96.6%; n=315) of the participants had heard of COVID-19 and knew that wearing face masks prevents infection (98.5%; n=321). Television was the source of information for most (53.7%, n=175) participants. There was a significant difference (p<.05) between respondents who knew the COVID-19 prevention protocols and those who did not (χ2=0.10; df=1;p=.00).

CONCLUSION

There was a high level of knowledge and a moderate level of practice of COVID-19 prevention protocols. Television was an important medium for community health education. Ministries of health can utilise mass media for continuous population education on COVID-19 and other infectious diseases.