bluuebunny/crossref_metadata_2025 huggingface dataset:
Floristic survey of vascular plants of the Parque Estadual da Pedra Selada, Rio de Janeiro, Brazil
Authors: Waga Isabela , Costa Andrea , Mynssen Claudine , Fernandez Eduardo , Guimarães Elsie , Saleme Fernanda , Queiroz George , Antar Guilherme , Lima Haroldo , Marques Hemily , Deccache Lara , Cardoso Leandro , Giacomin Leandro , Barbosa Maria Regina de V. , Gomes Mario , Morim Marli , Silva Otávio , Fiaschi Pedro , Moraes Pedro , Forzza Rafaela , Andrade Renon , Dória Thaís , Penedo Thiago , Bochorny Thuane , Verdi Marcio
Published: October 2024

The Atlantic Forest is one of the most diverse and threatened phytogeographical domains in the world. Despite that, it includes regions with poor floristic knowledge, even in protected areas. Although the importance of protected areas in conserving the Atlantic Forest hotspot is undisputed, it is necessary to recognise the floristic richness of these areas to propose effective conservation actions. In this sense, online databases have proved to be a promising tool for compiling species lists with relevant biodiversity information. This study is based on the list of vascular plants of the "Parque Estadual da Pedra Selada", published in the "Catálogo de Plantas das Unidades de Conservação do Brasil". It summarises the species richness, endemism and conservation status of this protected area.

The published list of vascular plants was based on data obtained from herbarium collections available in online databases. A total of 303 species have been recorded for the "Parque Estadual da Pedra Selada," of which 297 are native to Brazil, 78 are endemic to the Brazilian Atlantic Forest, and seven are endemic to the State of Rio de Janeiro. More than 60% of the species are woody, and more than 40% are trees. Eight threatened species (Endangered – EN and Vulnerable – VU), of which five are endemic to the State of Rio de Janeiro, are housed in this protected area. One species was classified as Data Deficient (DD). Our results increase the knowledge of the Atlantic Forest flora in the State of Rio de Janeiro and support effective conservation planning for this protected area.
Benchmarking the discrimination power of commonly used markers and amplicons in marine fish (e)DNA (meta)barcoding
Authors: Fontes João T. , Katoh Kazutaka , Pires Rui , Soares Pedro , Costa Filipe O.
Published: October 2024

Environmental DNA (eDNA) metabarcoding is revolutionising the study of aquatic ecosystems, enabling high-throughput analysis of biodiversity with minimal disturbance. Despite its potential to support fisheries management, species identification and downstream analysis reliability are hindered by the lack of standardisation in DNA fragment choice. This study compares the species discrimination power of three markers used in marine fish (e)DNA (meta)barcoding – 12S rRNA, 16S rRNA and cytochrome oxidase subunit I (COI) – as well as two amplicons for each. We analysed sequences from NCBI GenBank for 10 orders of Actinopterygii (ray-finned fishes), including mitochondrial genomes. We assessed species discrimination by determining the percentage of monophyletic species in Neighbour-Joining trees and calculating congeneric divergences for two datasets: one with genomic regions extracted from mitochondrial genomes (771 species) and another with independent sequences for each region (3,879 species). Amongst (meta)barcoding amplicons in the mitochondrial genomes’ dataset, the COI Folmer and Leray-Lobo regions had the highest discriminatory power, with 89.2% and 87.0% monophyletic species, respectively, while the 12S Teleo region had the lowest at 71.6%. Conversely, using independent sequences of these amplicons, Folmer and Leray-Lobo had the lowest percentages of monophyletic species, at 64.8% and 63.5%, respectively, while Actinopterygii 16S (Ac16S) had the highest at 83.0%. Species discrimination is influenced by the marker’s evolutionary rate, fragment length, target fish order and the quality of reference sequence data. We recommend considering species discriminatory power differences for amplicon selection, especially for species-level identifications. We advise a standard multi-marker approach under certain scenarios, particularly when the presence of close congeneric species is expected.
The ABCs of Leadership: How to Inspire Others
Authors: Trepanier Sylvain
Published: October 2024

The most effective way to lead through others is through inspiration. Inspiring others is the ability to encourage others to achieve agreed-on and predetermined goals. Plenty of behaviors are known to solicit inspiration. In this column, we propose a simple list of behaviors that promote inspiration, such as showing Appreciation, fostering a sense of Belonging, and demonstrating Curiosity and Compassion: the ABCs of leadership.

[
J Contin Educ Nurs.
2024;55(10):467–468.]
Emphasizing the Environmental Issue by Machine Learning-Based Sentiment Analysis
Authors: Kumar Sanjay , Rajani D. , Dutt Amit , Poornima E. , Reddy M. Mahender
Published: October 2024

In many academic disciplines, social media has shown its use as a technique for extracting and analysing public opinion. Exploration of unstructured information in thriving social mass media platforms that provide immediate public feedback and also record long-term information might reveal valuable information. Environmental scientists have seen the potential of public opinion and have undertaken much research on this issue. This paper centres its investigation on the extraction of environmental-related information from social media language, specifically focusing on sentiment analysis. This topic aligns with the field of Data Science & Sustainability. The contemporary information science community is mostly concerned with subjects that intersect with environmental concerns and their wider ramifications on sustainability.
Depicting Sustainability Awareness in Turkey-Syria Earthquake News Coverage via Sentiment Analysis
Authors: Polyakova Oksana , Kuzina Maria
Published: October 2024

In contemporary society, the mass media plays a pivotal role in shaping public perceptions, particularly in the dissemination of information following significant natural disasters. This manuscript proposes to scrutinise the representation of sustainability awareness in the news reporting pertaining to the Turkey-Syria earthquake by three predominant news organisations: ABC, CNN, and Fox. In the wake of the devastating Turkey-Syria earthquakes, the role of media in shaping public perception and awareness of sustainability practices has become increasingly critical. Sentiment analysis, a computational technique that assesses the emotional tone within a body of text, provides valuable insights into how news coverage reflects and influences public perception regarding environmental and sustainability issues. This study aims to explore the representation of interpersonal discourse in news coverage following a natural cataclysm, leveraging sentiment analysis to decode the underlying narratives and emotional responses.
Analysis of Corporation Trends in Environmental Protection Using VOS Viewer
Authors: Yakoob S. K. , Senthil Kumar A. , Sreenivasulu Gunji , Babu D. Venkata Srihari , Selvan R. Senthamil
Published: October 2024

Research on environmental protection is the subject of this work, which analyses recent tendencies in collaboration. The examination of international cooperation in environmental protection in light of the COVID-19 pandemic's effects led to the formation of a united system of research method interrelationships in the area of bibliometric approach implementation. Utilise a specialised software package called VOSViewer to provide a consistent visualisation of the bibliometric data that was analysed. Five distinct areas of study were identified: the first two deal with COVID-19 and biosafety as they pertain to public health; The third one explores international efforts to curb greenhouse gas emissions and their impact on the environment, while the fourth one brings together many subfields of economics that are pertinent to environmental control and management.
Effect on Manufacturing Industries Benefit From Life Cycle Sustainability Assessment of Environmental and Social Criteria
Authors: Reddy M. Siva Swetha , Sharfunisa N. , Prabakaran C. , Dharsini L. Priya , Shrivastava Preshni , Selvan R. Senthamil
Published: October 2024

Governments and groups have recently put pressure on industrial businesses to safeguard people and the environment, use natural resources ethically and transparently, and lessen their influence on regional and global ecosystems. Professionals and academics want to improve a product or service's life cycle to meet sustainability standards and create value. The significance of minimising goods and services' environmental effects while maximising their beneficial benefits to the economy, society, and environment is expanding. This research looks at how manufacturers may include social and environmental concerns into life cycle strategies for their products and services by using the life cycle sustainability assessment (LCSA) methodology. A new method for assessing manufacturing companies' environmental and social effects uses environmental priority strategy (EPS) as an LCSA tool regarding outcomes monetisation and Big Data Analytics (BDA) technology.
Development of Sustainable Goals Emissions Reduction Value to Measure Climate Change
Authors: Murugan J. Bala , Dharsini L. Priya , Prabakaran C. , Ranjit P. S. , Menaka S. , Selvan R. Senthamil
Published: October 2024

The Sustainable Development Goals, or SDGs, goal indicators and the steps taken to slow down climate change have trade-offs and synergies. Although some research has evaluated these linkages, nothing is known about how much of an interaction there is. This section illustrates how reducing CO2 emissions relates to the SDGs. They created the “marginal SDG-emissions-reduction values (MSVs),” which show how a unit decrease in CO2 emissions affects certain SDG indicators on a marginal basis. This measure was utilised and may be used for national evaluations. They discovered significant correlations between rates of CO2 emission reduction and several SDG objectives. For example, a 1% reduction in CO2 may save 0.57% of premature deaths linked to air pollution (SDG3), whereas the same CO2 reduction can result in a 0.026% drop in mean species richness (SDG15) (excluding the effects of climate change). Our results help evaluate the implications of CO2 emissions reduction objectives for the SDGs, which will assist in informing national climate strategies.
Analysing Public Sentiment Towards Climate Change Using Natural Language Processing
Authors: Dinesh G. , Sajja Guna Sekhar , Naik Shivani , Patro Pramoda , Anand M. Clement Joe
Published: October 2024

Climate change's effects on people's well-being provide new and varied concerns. These risks are expected to intensify and pose a continued threat to human safety unless decisive action is taken based on credible data. The ever-increasing progress in data and The broad availability and use of social media platforms have been made possible by advancements in communication technology. People voice their views on a variety of topics, including the critical problem of climate change, via social media sites like Twitter and Facebook. With so much content on social media on climate change, it's important to sift through it all to find the good stuff. To assess the tone of climate change-related tweets, this study uses natural language processing (NLP) methods. ClimateBERT, a pre-prepared model particularly tailored to the field of atmosphere change, is an individual instance. The aim is to identify patterns in the public's perception of climate change and comprehend people's emotions towards it.
Combining Clinical Data With Neuro Images to Identify the Treatment Resistant in Depression by NLP
Authors: Reddy Santosh , Sreelatha P. K. , Malipatil Ashwini R.
Published: October 2024

Predicting treatment-resistant depression (TRD) is difficult, even though 21% of individuals with depression who get therapy do not achieve remission. The purpose of this research is to use structured data from electronic health records, brain morphology, & natural language processing to create a multimodal forecast model for TRD that can be explained. A total of 248 patients who recently had a period of depression were included. Combining topic probability from clinical notes with separate components-map weights from brain T1-weighted MRI, and chose tabular dataset attributes, TRD-predictive models were created. All of the models used five-fold cross-validation to apply the XGBoost algorithm. The area under the receiver's operating characteristic was 0.795 for the model that utilized all data sources, then for models that used structured data and brain MRI together, and finally for models that used brain MRI and medical records separately. (0.771), (0.763) plus structured data, (0.729) plus clinical notes, (0.704) plus structured data,
Sustainable Climate Change Analysis of Renewable Power
Authors: Murugan J. Bala , Dharsini L.Priya , Prabakaran C. , Ranjit P. S. , Kambala Santha Kumari
Published: October 2024

Human well-being is enhanced by energy development, but there are environmental costs as well. While switching from fossil fuels to renewable energy might slow down global warming, it could also make it more difficult to accomplish some or all of the 18 Sustainable Development Goals (SDGs). In this research, the researcher builds a complete roadmap of solar and wind energy using an innovative systems approach to foresee and ameliorate the implications of a shift to a low-carbon future while making sure that SDGs and climate objectives are mutually reinforcing. The interdisciplinary approach started with a two-day workshop on research prioritisation, which was followed by an evaluation of public funding in renewable energy. Six study issues that proactively address the environmental responsibility of renewable energy were highlighted by fifty-eight expert workshop participants. The researcher then determined connections between each of the 17 SDGs and the six study subjects. To evaluate the research maturation of these issues, the researcher lastly performed a scientiometric study
Analysis of Contemporary Trends in Industrial Stability Across Various Countries Through Text Mining
Authors: Alhazemi A. , Sivaraman P. R. , Sharma Abhishek , Sharma Ankitha , Anand M. Clement Joe
Published: October 2024

Sustainability in business is more important than ever before due to the current spike in environmental concerns. Throughout the globe, people are looking for businesses to operate in a way that doesn't affect the environment too much while fostering a harmonious relationship between the company, the environment, and society. Companies often disclose their activities through environmental and social responsibility (ESR) reports. This study seeks to comprehend and evaluate current patterns in CSR reports submitted by Fortune 500 corporations via the use of text-mining techniques. It looks at sustainability reports from different nations and different sectors and contrasts their emphasis on economic, social, and governmental sustainability components. According to the study's findings, sustainability reports differ in their emphasis depending on many criteria, including the company's size, industry, duration on the Fortune 500 list, and country of origin. As a result, it's useful for learning why the organisation is so concerned with certain aspects of corporate sustainability.
Sentiment Analysis and Text Mining in Environmental Sustainability and Climate Change
Authors: Freeda Adline R. , Anju A. , Venket Krithikaa , Dhaya Kanthavel , Kanthavel R. , Vijay Frank
Published: October 2024

The necessity for novel methods to track and comprehend public opinion and conversation around climate change and environmental sustainability has been highlighted by the growing urgency of tackling these concerns. With the use of natural language processing (NLP) techniques, text mining and sentiment analysis provide effective methods for gleaning insightful information from large volumes of textual data.Data from social media, news stories, policy documents, and scholarly publications can all be analyzed to gauge public opinion, spot new trends, and gauge how well communication tactics are working. The results show important discourse and mood patterns that can guide policy decisions, enhance communication tactics, and encourage more public action and knowledge in the direction of environmental sustainability. The present study showcases the efficaciousness of text mining and sentiment analysis as indispensable instruments in the continuous endeavor to mitigate climate change and foster sustainable methodologies.
The Effects of Ambient Conditions on Helicopter Harmonic Noise Radiation: Theory and Experiment
Authors:   US Army, Sim Ben ,   NASA Langley Research Center, Greenwood Eric , Boyd D.
Published: October 2024

The effects of ambient atmospheric conditions, air temperature and density, on rotor harmonic noise radiation are characterized using theoretical models and experimental measurements of helicopter noise collected at three different test sites at elevations ranging from sea level to 7000 ft above sea level. Significant changes in the thickness, loading, and blade-vortex interaction noise levels and radiation directions are observed across the different test sites for an AS350 helicopter flying at the same indicated airspeed and gross weight. However, the radiated noise is shown to scale with ambient pressure when the flight condition of the helicopter is defined in nondimensional terms. Although the effective tip Mach number is identified as the primary governing parameter for thickness noise, the nondimensional weight coefficient also impacts lower harmonic loading noise levels, which contribute strongly to low frequency harmonic noise radiation both in and out of the plane of the horizon. Strategies for maintaining the same nondimensional rotor operating condition under different ambient conditions are developed using an analytical model of single main rotor helicopter trim and confirmed using a CAMRAD II model of the AS350 helicopter. The ability of the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique to generalize noise measurements made under one set of ambient conditions to make accurate noise predictions under other ambient conditions is also validated.
Analytical Identification of Blade-Vortex Interaction Noise Controller Suited for Miniature Trailing Edge Effectors
Authors:   University of Rome La Sapienza, Modini Sara ,   Roma Tre University, Bernardini Giovanni , Graziani Giorgio , Gennaretti Massimo
Published: October 2024

With the aim of alleviating the noise annoyance generated by helicopter main rotors in BVI flight conditions, the present work focuses on the presentation and application of a methodology for the identification of a multi-cyclic harmonic controller based on the actuation of Micro-Trailing Edge Effectors. Because of their low-power requirements, these are particularly suited for this kind of high-frequency applications. The control devices setting is selected on the basis of the BVI scenario, while the actuation law is efficiently identified through an analytical process based on the Theodorsen theory. The proposed methodology is validated by application to a realistic helicopter main rotor in descent flight, and preliminary results concerning its capability to alleviate BVI loads and associated emitted noise are presented and discussed. For controller identification and validation purposes, Micro-Trailing Edge Effectors are replaced by trailing edge plain flaps which provide equivalent aerodynamic responses suitably predicted by potential-flow aerodynamic solvers.
Predictions of Transonic Rotor Noise by KFWH Method with A Permeable Self-Adaptive Integration Surface
Authors:   Nanjing University of Aeronautics and Astronautics, Si-Yu Chen , Qi-Jun Zhao , Zheng Zhu , Yi-Yang Ma
Published: October 2024

In this paper, a new permeable self-adaptive integration surface is developed for the evaluation of transonic rotor noise by KFWH method. Firstly, the nonlinear near flowfield solution is computed by a N-S solver and as input for acoustic calculations by KFWH formula. Then, the acoustic pressure predictions of the UH-1 model rotor with cylinder-shaped integration surfaces at different locations are shown, which reveals that the results calculated by KFWH method show a large sensitivity to the location of integration surface. In order to avoid the uncertainties in determining the cylinder-shaped integration surface, a new permeable self-adaptive integration surface is determined by pressure gradient or density adaptively according to some principles. Then, the acoustic pressure of UH-1 model rotor at different tip Mach numbers and different observer locations are simulated. In comparison with cylinder-shaped integration surface, the self-adaptive integration surface, whether it is determined by pressure gradient or by density, can both reach higher accuracy in the prediction of transonic rotor noise. Moreover, the numerical results with self-adaptive integration surfaces given by density perturbation value confirm to the experimental data better.
Parametric Investigation of the Effect of Hub Pitching Moment on Blade Vortex Interaction (BVI) Noise of an Isolated Rotor
Authors:   NASA Ames Research Center, Malpica Carlos ,   NASA Langley Research Center, Greenwood Eric ,   US Army Aviation Development Directorate, Sim Ben
Published: October 2024

At the most fundamental level, main rotor loading noise is caused by the harmonically-varying aerodynamic loads (acoustic pressures) exerted by the rotating blades on the air. Rotorcraft main rotor noise is therefore, in principle, a function of rotor control inputs, and thus the forces and moments required to achieve steady, or "trim", flight equilibrium. In certain flight conditions, the ensuing aerodynamic loading on the rotor(s) can result in highly obtrusive harmonic noise. The effect of the propulsive force, or X-force, on Blade-Vortex Interaction (BVI) noise is well documented. This paper presents an acoustics parametric sensitivity analysis of the effect of varying rotor aerodynamic pitch hub trim moments on BVI noise radiated by an S-70 helicopter main rotor. Results show that changing the hub pitching moment for an isolated rotor, trimmed in nominal 80 knot, 6 and 12 deg descent, flight conditions, alters the miss distance between the blades and the vortex in ways that have varied and noticeable effects on the BVI radiated-noise directionality. Peak BVI noise level is however not significantly altered. The application of hub pitching moment allows the attitude of the fuselage to be controlled; for example, to compensate for the uncomfortable change in fuselage pitch attitude introduced by a fuselage-mounted X-force controller.
System Identification of a Hover-Capable Robotic Hummingbird
Authors:   Texas A&M University, Coleman David , Benedict Moble
Published: October 2024

This paper presents the first ever linear system identification of the flight dynamics of a hover-capable robotic hummingbird which utilizes only two wings for flying as well as for all its control and stabilization. The vehicle was developed in-house, using state-of-the-art materials, electronics, and innovative design/fabrication techniques, and a description of its development is provided. Systematic experimental studies were conducted to develop flexible, aeroelastically tailored wings, along with novel wing kinematic modulation mechanisms for controlling roll, pitch and yaw. Additionally, a custom, lightweight, autopilot implementing PID control was developed, and after a series of rigorous flight testing, the trim and feedback gains were determined which allowed stable, hovering flight. Once this was achieved, a motion capture camera system was used to track the position and attitude of the vehicle during flight tests which involved providing a series of inputs to excite the vehicle modes and measuring the response. A linearized six degree of freedom state-space model for hovering flight was then extracted from this data using time domain system identification. An analysis of the eigenstate of the model reveals four modes present: an unstable mode that excites all the vehicle states; a stable mode that excites yaw and translational motion; and two oscillatory modes, one stable and one marginally unstable, both responsible for translational and rotational excitation about all axes. This finally demonstrates experimentally for the first time the unstable nature of two-winged, hover-capable flapping flight. These four modes, which show a strong coupling between the longitudinal and lateral dynamics, suggest that assumptions which decouple longitudinal and lateral degrees of freedom may not be valid for this type of flight. Additionally, this unstable, coupled dynamics demonstrates definitively the superior agility inherent in this type of aerial locomotion.
Design and Development of a Scaled Quadrotor Biplane with Variable Pitch Proprotors for Rapid Payload Delivery
Authors:   University of Maryland, Phillips Brandyn ,   Technion - Israel Institute of Technology, Rand Omri , Hrishikeshavan Vikram , Chopra Inderjit
Published: October 2024

With the introduction of multiple mission roles, air vehicles such as quadcopters are being put under increasing performance strain such as faster travel times, longer loiter endurance, and higher payload capacity. These aspects are driving experimentation with hybrid air vehicles. This paper discusses the design and development of one such hybrid vehicle, the quad rotor biplane, that is adapted for package delivery capability. This vehicle configuration has four proprotors and two wings situated in a biplane configuration. It takes of as a helicopter in tail-sitter configuration and uses differential thrust to pitch into forward flight configuration, and even control the vehicle control moments. The vehicle has a gross takeoff weight of 3.63 Kg with a 0.45 kg payload capacity. The biplane wings are a uniform airfoil with a Wortmann FX63-137 airfoil. These wings have a span of 1.02 m and a chord length of 0.254 m . To facilitate package delivery, a dual auger mechanism driven by servomotors is used to push the packages out of the payload area and maintain the center of gravity. A solenoid mechanism ensures the payload door stays locked while the vehicle is in transition flight. To minimize trade-off in performance between hover and fixed-wing modes, a variable pitch mechanism was incorporated. Performance measurements in the wind tunnel showed that each proprotor requires a minimum of 100 W at 0 deg pitch for hover while only requiring 24 W at a forward speed of 15 m/s with a pitch of 26°. The chord and twist distribution were further optimized using a non-linear optimizer and a hover-forward flight Pareto frontier optimizer. The optimum twist/chord yielded a 5% reduction in minimum power over baseline thereby stressing that the variable pitch capability is an important parameter. The vehicle was successfully tested in hover flight mode along with a remotely controlled aerial package delivery.
Gust Disturbance Rejection Study of a Cyclocopter Micro Air Vehicle
Authors:   University of Maryland, Shrestha Elena ,   Texas A&M University, Benedict Moble , Yeo Derrick , Hrishikeshavan Vikram , Chopra Inderjit
Published: October 2024

This paper describes the comprehensive wind tunnel studies conducted on a 550g cyclocopter micro air vehicle to determine its gust disturbance rejection capability and the development of a synthetic gust generation device capable of providing up to 4m/s step gust input for free flight experiments. The cyclocopter uses two cyclorotors with thrust vectoring capability, as well as a vertical thrusting nose rotor to counteract pitching moment produced by the cyclorotors. Planar gusts along the longitudinal and lateral axis of the cyclocopter were systematically studied. The response of the vehicle to these gust modes were evaluated in a succession of steps using 1-DOF pitch and roll gimbal stands and a 5-DOF setup (constrained only in lateral translation) in front of an open-jet wind tunnel. The cyclocopter uses differential rotational speed of the cyclorotors to counteract lateral gusts. To tolerate a gust perturbation along the longitudinal axis, the cyclocopter has capability to use either the pitching moment generated by the nose rotor or the propulsive force effected by vectoring the cyclorotors' thrust towards the freestream. Results from the 5-DOF experiments for the cyclocopter operating at 1400rpm showed that the thrust vectoring technique enabled the vehicle to tolerate up to 6m/s gust perturbation along the longitudinal axis compared to 2.5m/s when relying on pitch control. While the current 550g cyclocopter has demonstrated level forward flight up to 5m/s, it has the capability to achieve up to 6m/s.
Experiment Demonstrating Reduction of Dynamic Stall by a Back-flow Flap
Authors:   DLR, Gardner Anthony , Opitz Steffen , Wolf C. , Merz Christoph
Published: October 2024

A back-flow flap attached to the suction side of an airfoil is investigated in both passively and actively actuated modes for the control of dynamic stall. Experiments in a low-speed wind tunnel at 50 m/s were used to characterise the reduction in dynamic stall using pressure measurements on the midline of an airfoil. The pitching moment peak is reduced by an average of 25% for all deep stall test cases for active actuation of the flap, while for passive actuation the pitching moment peak is reduced by 19%. In each case the maximum lift remained the same, while the peak drag increased by an average of 2.5% for the active flap, and by 0.9% for the passive flap. With the flap closed at low angles of attack, the reference values of the airfoil are retained.
Computations of Combustion-Powered Actuation for Dynamic Stall Suppression
Authors:   United Technologies Research Center, Jee Solkeun ,   Georgia Institute of Technology, Crittenden Thomas , Bowles Patrick , Matalanis Claude , Min Byung-Young , Wake Brian , Glezer Ari
Published: October 2024

A computational framework for the simulation of dynamic stall suppression with combustion-powered actuation (COMPACT) is validated against wind tunnel experimental results on a VR-12 airfoil. COMPACT slots are located at 10% chord from the leading edge of the airfoil and directed tangentially along the suction-side surface. Helicopter rotor-relevant flow conditions are used in the study. A computationally efficient two-dimensional approach, based on unsteady Reynolds-averaged Navier-Stokes (RANS), is compared in detail against the baseline and the modified airfoils with COMPACT, using aerodynamic forces, pressure profiles, and flow-field data. The two-dimensional RANS approach predicts baseline static and dynamic stall very well. Most of the differences between the computational and experimental results are within two standard deviations of the experimental data. The current framework demonstrates an ability to predict COMPACT efficacy across the experimental dataset. Enhanced aerodynamic lift on the downstroke of the pitching cycle due to COMPACT is well predicted, and the cycle-averaged lift enhancement computed is within 3% of the test data. Differences with experimental data are discussed with a focus on three-dimensional features not included in the simulations and the limited computational model for COMPACT.
Aerodynamic Performance Analysis for Iced Rotor based on New Three-Dimensional Rotor Icing Model
Authors:   Nanjing University of Aeronautics and Astronautics, Xi Chen , Qi-jun Zhao
Published: October 2024

A new numerical method for predicting ice accretion on helicopter rotor is established. The ice amount is calculated using a coupling method of 3-D CFD and 3-D icing model. Firstly, the orthogonal and body-fitted grids are generated around rotor blade by interpolating and folding approach of section airfoil grid. Then, the CFD simulation method for 3-D flowfield around the blade is established by solving the unsteady RANS equations with Spalart-Allmaras turbulence model. Based on the Eulerian approach, the conservation equations of mass and momentum are solved to obtain the droplet flowfield properties on the same grid used in CFD simulations, and the multistage Runge-Kutta scheme is employed in the temporal discretization. Followed that, combined with the characters of rotor blade motion, a 3-D icing model considering the influences of the centrifugal force, the movement of water film and the variation of the azimuthal angle is put forward. The comparisons between the calculated results and experimental data about the ice accretion on rotor in hover and in forward flight indicate that the present method is effective. At last, the effects of the atmospheric temperature on the icing process and the aerodynamic performance of the iced rotor are analyzed. At the warmer sub-freezing temperatures, ice is not easy to form near the blade tip, and blade sectional lift along the spanwise direction from 45% to 65%R is decreased obviously. There is a significant deterioration in the rotor required power and the lift coefficient with temperature dropping, resulting in the decrease of the Figure of Merit of rotor in hover (FM is reduced by about 7.1% at the temperature of -28°C).
Improvements in the Helios Rotorcraft Simulation Code
Authors:   US Army, Wissink Andrew ,   Science and Technology Corp., Jayaraman Buvana ,   US Navy, Forsythe James ,   Parallel Geometric Algorithms, Sitaraman Jayanarayanan ,   Kitware Inc., Bauer Andrew , Jain Rohit , Potsdam Mark , Leffell Joshua , Roget Beatrice , Lakshminarayan Vinod
Published: October 2024

An overview of capabilities recently introduced or in development in the HPCMP CREATE™-AV Helios high-fidelity rotorcraft simulation code is presented. These include an implicit off-body Cartesian solver to support Reynolds-Averaged Navier-Stokes (RANS) or Detached Eddy Simulation (DES) in the wake; a body hierarchy formulation to support generalized body motion, coupled wing/rotor aeroelastics and maneuvering flight; a strand-grid based near-body solver intended to support enhanced automation and efficiency; the inclusion of two validated unstructured near-body solvers - NASA's FUN3D and CREATE-AV Kestrel's kCFD; runtime in situ visualization improvements with unsteady particle tracing with restart; and new pre- and post-processing Graphical User Interfaces (GUIs) for ease of use. Future advanced capabilities for Helios are cited. Example application of these new capabilities are presented.
Reliability-Focused Design of Advanced Rotorcraft Configurations
Authors:   US Army Aviation Development Directorate, Scott Robert
Published: October 2024

An approach to the conceptual design of rotorcraft is presented which incorporates cost and reliability assessment methods from various multidisciplinary studies to address the cost premium historically associated with vertical flight. The methodology builds upon previous reliability-focused rotorcraft design work to survey both a variety of rotorcraft configurations and a wider range of technology insertion intended to improve overall aircraft reliability and availability. The methodology is applied to a sensitivity study of technology insertion. The tradeoffs in design effects and life-cycle cost components are observed with the aim of finding the level of reliability investment which results in the minimum life-cycle cost for a given set of assumptions related to design and operational conditions. The study concludes by discussing the implications of the reliability tradespace investigation for future rotorcraft development and procurement programs.
Electric Multirotor Propulsion System Optimization for Mission Objectives
Authors:   Georgia Institute of Technology, Bershadsky Dmitry , Johnson Eric , Haviland Stephen
Published: October 2024

This paper describes a proposed method for the design of a propulsion system of generic single and multirotor vehicles. With this methodology, a designer is able to generate a vehicle that will be capable of completing a specific mission. The method allows for optimization of drive components in terms of physical parameters such as total weight, minimum wing chord, propeller pitch, etc. The considered propulsion system components are motors, propellers, batteries, and electronic speed controllers (ESCs) and associated drive wiring. The study considers battery powered vehicles, although, with simple modifications, the method remains valid for other electrical energy sources. The method is generic enough to apply to both standard and non-standard vehicle configurations. The method’s output is a set of propulsion system parameters, and chassis parameters when applicable, that will accomplish a specific mission. A vehicle may be sized for lightest gross takeoff weight (GTOW), smallest wing, highest efficiency or climb rates, and/or other performance goals, depending on the desired objective(s).
Acoustic Assessment for Design and Analysis of Rotorcraft
Authors:   The Pennsylvania State University, Sharma Kalki , Brentner Kenneth
Published: October 2024

The purpose of this paper is to propose a noise prediction system for use in the design cycle of rotorcraft. Along with predicting the noise, the system sizes rotorcraft for user specified constraints and analyzes the performance for mission profiles and flight conditions. The noise prediction is performed using first principles and semi-empirical models, and the system is built to perform its tasks accurately and efficiently to allow for rapid turnaround of rotorcraft configurations by the designer. With the aid of this system, a designer can properly weigh the costs and benefits of a rotorcraft configuration not only on performance data, but also its acoustic impact.
Range and Endurance Tradeoffs on Personal Rotorcraft Design
Authors:   NASA Glenn Research Center, Snyder Christopher
Published: October 2024

Rotorcraft design has always been a challenging tradeoff among overall size, capabilities, complexity, and other factors based on available technology and customer requirements. Advancements in propulsion, energy systems and other technologies have enabled new vehicles and missions; complementary advances in analysis methods and tools enable exploration of these enhanced vehicles and the evolving mission design space. A system study was performed to better understand the interdependency between vehicle design and propulsion system capabilities versus hover / loiter requirements and range capability. Three representative vertical lift vehicles were developed to explore the tradeoff in capability between hover efficiency versus range and endurance capability. The vehicles were a single-main rotor helicopter, a tilt rotor, and a vertical take-off and landing (VTOL) aircraft. Vehicle capability was limited to two or three people (including pilot or crew) and maximum range within one hour of flight (100-200 miles, depending on vehicle). Two types of propulsion and energy storage systems were used in this study. First was traditional hydrocarbon-fueled cycles (such as Otto, diesel or gas turbine cycles). Second was an all-electric system using electric motors, power management and distribution, assuming batteries for energy storage, with the possibility of hydrocarbon-fueled range extenders. The high power requirements for hover significantly reduced mission radius capability. Loiter was less power intensive, resulting in about 1/2 the equivalent mission radius penalty. With so many design variables, the VTOL aircraft has the potential to perform well for a variety of missions. This vehicle is a good candidate for additional study; component model development is also required to adequately assess performance over the design space of interest.
Bell 525 Airspeed Calibration Prior to First Flight
Authors:   Bell Helicopters, Mitchell Jonathan , Brand Albert , Hill Matthew , Wu Nathan , Singh Ajay
Published: October 2024

Bell Helicopter's 525 Relentless will be the world's first commercially certified fly-by-wire helicopter. As a fully computer controlled aircraft, the design aims at higher safety through reduced pilot workload, increased situational awareness, and improved handling qualities. The flight control system that achieves these results operates with numerous redundant sensors that provide flight data and feedback to the flight control logic. This paper describes the development of the Bell 525's redundant Pitot static airspeed system, showing how computational fluid dynamics (CFD) models were used to perform initial calibration of the triplex system far ahead of first flight. Since air data readings interact with the flight control logic, it was important to have a reasonable airspeed calibration available for first flight. The Bell 525 aerodynamics team developed an analytical approach to model the triplex airspeed system to account for position error across the flight envelope. The analysis developed calibration curves for forward flight, descent, and climbs to meet FAA rules for accuracy. The resulting process has allowed the 525 to conduct its first flight and full envelope expansion with an accurate and reliable production airspeed system.
A Rapid and Affordable Approach to Insert the Future Airborne Capability Environment (FACE) into Fielded Open System Architecture (OSA) Systems
Authors:   Rockwell Collins, Johnson Tony , Burns Stephanie , Gomez Patrick , Dusio Joe
Published: October 2024

In an environment of limited and dynamic defense funding, affordable approaches are needed to maximize deployment of innovative capabilities across entire fleets of military aircraft. The United States (US) Department of Defense (DoD) is supporting the use of new open system architecture solutions such as the Future Airborne Capability Environment (FACE™) Technical Standard for use on their respective platforms. The goals of the FACE Standard include reducing lifecycle costs and enabling rapid integration of innovative capabilities in the form of software applications that are reusable across multiple aircraft platforms, both current and new; regardless of the manufacturer or supplier. This paper describes technical methodologies to incorporate FACE technologies into existing platforms using a software-only upgrade approach. The US DoD currently has a large inventory of fielded platforms with avionics solutions based on Rockwell Collins Flight2™ Open Systems Architecture (OSA) - an architecture reused on over 50 platforms including Army Rotary Wing platforms along with Navy/Marine, Coast Guard, Air Force and International rotary and fixed wing aircraft. A subset of these Flight2 OSA platforms is better known as Common Avionics Architecture System (CAAS). A comparison of the FACE architecture with the Flight2/CAAS architecture is provided along with an example of integrating a FACE application providing RNP RNAV capabilities. This approach maximizes previous DoD system investments to enable rapid and affordable deployment of reusable applications that align to the FACE Standard.
Transport Aircraft Seating in Rotorcraft Crash Testing
Authors:   Federal Aviation Administration, Pellettiere Joseph , Taylor Amanda
Published: October 2024

The Federal Aviation Administration (FAA) has standards and regulations that are designed to protect aircraft occupants in the event of a crash. These standards focus primarily on horizontal and vertical impact protection, and measure the dynamic performance of the seating system and occupant restraints. Currently no requirement for full-scale crashworthiness testing exists due to the cost prohibitive nature of conducting such a test. The requirements were developed through review of research, existing requirements, modeling and simulation, and accident analysis. A drop of a Transport Rotorcraft Airframe Crash Testbed (TRACT), CH-46 airframe, at the National Aeronautics and Space Agency's Langley Research Center Landing and Impact Facility, provided an opportunity to investigate the performance of an airframe in a simulated crash condition. This provided full scale data on the performance of previously approved transport category aircraft seating systems. Passenger seats that were previously certified to 14 CFR § 25.562 aviation regulations with a 49 CFR § 572 50% Hybrid II Anthropomorphic Test Device (ATD) were included in the testing. It was expected that the real crash pulse measured at the floor, would differ from the certification tests and the performance of the seats would as well. The ATDs used in the crash test included the 50% Hybrid II, a 50% FAA Hybrid III, 5% Hybrid III and a 95% Hybrid III. Injuries in the spinal column are of concern, so lumbar loads were collected for all ATDs, in addition to head, chest and pelvis accelerations. The Part 25 Passenger seats remained attached to the floor structure; however the experimental sub floor structure failed for the forward occupants. The restraint system held the occupants in place, however the compressive lumbar loads measured were significantly higher than those seen in typical certification tests, and exceeded the regulatory limit of 1500 lb. Typical certification tests primarily use the 50% Hybrid II or an equivalent, which is the FAA Hybrid III. The main performance requirement during a vertical test is the compressive lumbar loads, but structural integrity is also evaluated. This testing demonstrated that seats dynamically qualified for lower impact severities (14 G) were able to maintain structural integrity but were not able to control spinal injury risk at this load level.
Evaluation of Aerospace Seat Belt Webbing Material Under Dynamic Test Conditions
Authors:   Federal Aviation Administration, Pellettiere Joseph ,   National Institute for Aviation Research, Huculak Robert , DeWeese Richard
Published: October 2024

There is no requirement for full-scale testing of either civil or military rotorcraft to certify a design as safe or crashworthy. The Federal Aviation Administration has a number of standards and regulations that are designed to protect occupants in the event of a crash. These standards focus primarily on frontal and vertical impact protection of the occupant seating system and those items in the cabin interior that surround the occupant. With the adoption of Title 14 Code of Federal Regulations (CFR) 29.562, as well as the corresponding portions of 14 CFR 23.562, 25.562, and 27.562, a seating system is comprised of the seat, all attachment hardware, and the restraint system. In this methodology, the attachments and the restraint are approved for use at the same time as the seat itself. One restraint cannot be readily swapped out for another restraint and any repairs of the restraint itself must return it back to its original specifications. Inherent material properties of common webbing materials may affect the dynamic response of the seat system. To determine how differences in elongation properties affect seat dynamic response, a test program using a rigid seat setup in different configurations with different webbing materials was conducted by the FAA. The selected configurations represented seats commonly in use. Both new and newly repaired belts were acquired for this study. As part of this test program, a second phase was conducted to investigate the effects of belt stiffness. Original belt webbing material and several replacement webbing material candidates were statically tested to determine their elongation properties. These belts were then subjected to the same test setup as in phase 1; however, unlike phase 1, only one seating configuration was tested. All these different belts were then subjected to dynamic impact tests using a rigid seat and the sled test pulse from Title 14 Code of Federal Regulations 25.562. No structural failures occurred in any of the tests. A trend was noted that higher belt stiffness resulted in less occupant excursion and higher belt loads. It was also noted that static belt stiffness can be used to characterize relative belt performance in dynamic tests. These data can be used to develop general guidelines on allowable webbing changes for previously approved seat belts.