bluuebunny/crossref_metadata_2025 huggingface dataset:
Konstruksi Identitas Kelompok Kriminal Remaja Perkotaan
Authors: Bambang Mudjiyanto  , Launa Launa , Fit Yanuar
Published: October 2024

This study This study aims to explore a number of information and empirical data to analyze the phenomenon of criminality and the process of forming the social identity of youth gangs as socio-cultural symptoms in the criminal landscape of urban cities. This type of research is characterized by qualitative with a constructivist paradigm and psycho-cultural approach. In the analysis, this study found a number of facts, that the phenomenon of teenage gangster, which is mostly inhabited by gen z' (15-23 years old), has long experienced a shift in orientation and behavior due to various internal and external influences. The shift in orientation and behavior has resulted in a number of symbolic constructions where urban youth gangs are perceived as troublemakers, violent actors, criminals, instigators of antisocial attitudes, and thrill seekers. The study findings show: there is a theoretical discrepancy to find a 'positive self-concept' space in urban youth criminal groups whose orientation and behavior have been infected by intolerant and antisocial symbols of group identity; and various social diseases, such as traumatic symptoms, psychosis, phobia, schizophrenia, bipolar, and obsessive compulsive disorder.
ABSTRAK
Studi ini bertujuan menelusuri sejumlah informasi dan data empiris guna menganalisis fenomena kriminalitas dan proses pembentukan identitas sosial geng remaja sebagai gejala sosio-kultural dalam lanskap kriminalitas kaum urban kota. Jenis penelitian ini berciri kualitatif dengan paradigma konstruktivis dan pendekatan psiko-budaya. Dalam analisis, kajian ini menemukan sejumlah fakta, bahwa fenomena gengster remaja yang mayoritas dihuni gen z’ (15-23 tahun) sejak lama telah mengalami pergeseran orientasi dan perilaku akibat berbagai pengaruh internal maupun eksternal. Pergeseran orientasi dan perilaku tersebut menghasilkan sejumlah konstruksi simbolik dimana geng remaja perkotaan dipersepsi sebagai pembuat onar, aktor kekerasan, pelaku kriminal, penyulut sikap antisosial, dan pemburu sensasi. Temuan studi menunjukkan: ada diskrepansi teoritis untuk menemukan ruang ‘konsep diri positif’ pada kelompok kriminal remaja kota yang orientasi dan perilakunya sudah terjangkit oleh simbol-simbol identitas kelompok yang intoleran dan antisosial; dan berbagai penyakit sosial, seperti gejala traumatik, psikosis, fobia, skizofrenia, bipolar, dan obsessive compulsive disorder.
Motif Mahasiswa Memilih Organisasi Eksternal (Studi Fenomenologi Pada Mahasiswa Universitas Singaperbangsa Karawang)
Authors: Nindya Handaru Viaduta K.  , Ana Fitriana Poerana  , Rastri Kusumaningrum
Published: October 2024

Students need a forum to realize the role that students have. Student organizations can be a forum for students to channel their talents, interests, potential and roles that can be developed in social responsibility through community service activities. Student organizations are divided into 2, namely intra-campus organizations (internal) and off-campus organizations (external). The focus of this research is the motive of students choosing off-campus organizations. This research uses qualitative research methods. This research uses a phenomenological approach, using Alfred Schutz's phenomenological theory. According to Alfred Schutz's Phenomenological Theory, the motivation of social action is the reason behind an action. Schutz makes a distinction between two categories of motives, namely because motive and in onrter to motive. Alfred Schutz uses past actions and future actions to explain and interpret social behavior. The informants of this research are students who choose off-campus organizations with purposive sampling technique. The results showed that the motive for students to choose off-campus organizations was the characterization of the chosen organization, the desire of organization members to improve soft skills, and recommendations or directions from relatives. Meanwhile, the purpose motives for students choosing off-campus organizations are gaining relationships, realizing personal goals, and sharing knowledge with others.
JWST/NIRISS Reveals the Water-rich “Steam World” Atmosphere of GJ 9827 d
Authors: Piaulet-Ghorayeb Caroline , Benneke Björn , Radica Michael , Raul Eshan , Coulombe Louis-Philippe , Ahrer Eva-Maria , Kubyshkina Daria , Howard Ward S. , Krissansen-Totton Joshua , MacDonald Ryan J. , Roy Pierre-Alexis , Louca Amy , Christie Duncan , Fournier-Tondreau Marylou , Allart Romain , Miguel Yamila , Schlichting Hilke E. , Welbanks Luis , Cadieux Charles , Dorn Caroline , Evans-Soma Thomas M. , Fortney Jonathan J. , Pierrehumbert Raymond , Lafrenière David , Acuña Lorena , Komacek Thaddeus , Innes Hamish , Beatty Thomas G. , Cloutier Ryan , Doyon René , Gagnebin Anna , Gapp Cyril , Knutson Heather A.
Published: October 2024

With sizable volatile envelopes but smaller radii than the solar system ice giants, sub-Neptunes have been revealed as one of the most common types of planet in the galaxy. While the spectroscopic characterization of larger sub-Neptunes (2.5–4 R
⊕) has revealed hydrogen-dominated atmospheres, smaller sub-Neptunes (1.6–2.5 R
⊕) could either host thin, rapidly evaporating, hydrogen-rich atmospheres or be stable, metal-rich “water worlds” with high mean molecular weight atmospheres and a fundamentally different formation and evolutionary history. Here, we present the 0.6–2.8 μm JWST/NIRISS/SOSS transmission spectrum of GJ 9827 d, the smallest (1.98 R
⊕) warm (T
eq,A=0.3 ∼ 620 K) sub-Neptune where atmospheric absorbers have been detected to date. Our two transit observations with NIRISS/SOSS, combined with the existing HST/WFC3 spectrum, enable us to break the clouds–metallicity degeneracy. We detect water in a highly metal-enriched “steam world” atmosphere (O/H of ∼4 by mass and H2O found to be the background gas with a volume mixing ratio of >31%). We further show that these results are robust to stellar contamination through the transit light source effect. We do not detect escaping metastable He, which, combined with previous nondetections of escaping He and H, supports the steam atmosphere scenario. In water-rich atmospheres, hydrogen loss driven by water photolysis happens predominantly in the ionized form, which eludes observational constraints. We also detect several flares in the NIRISS/SOSS light curves with far-UV energies of the order of 1030 erg, highlighting the active nature of the star. Further atmospheric characterization of GJ 9827 d probing carbon or sulfur species could reveal the origin of its high metal enrichment.
nifty-ls: Fast and Accurate Lomb–Scargle Periodograms Using a Non-uniform FFT
Authors: Garrison Lehman H. , Foreman-Mackey Dan , Shih Yu-hsuan , Barnett Alex
Published: October 2024

We present nifty-ls, a software package for fast and accurate evaluation of the Lomb–Scargle periodogram. nifty-ls leverages the fact that Lomb–Scargle can be computed using a non-uniform fast Fourier transform (NUFFT), which we evaluate with the Flatiron Institute NUFFT package (finufft). This approach achieves a many-fold speedup over the Press & Rybicki method as implemented in Astropy and is simultaneously many orders of magnitude more accurate. nifty-ls also supports fast evaluation on GPUs via CUDA and integrates with the Astropy Lomb–Scargle interface. nifty-ls is publicly available at https://github.com/flatironinstitute/nifty-ls/.
Redescription of Microphysogobio tungtingensis (Nichols, 1926) with the description of a new species of the genus (Cypriniformes, Gobionidae) from southern China
Authors: Sun Zhi-Xian , Tang Wen-Qiao , Zhao Ya-Hui
Published: October 2024

Although Microphysogobio tungtingensis (Nichols, 1926) has been treated valid since it was described, its morphology remains vague, especially when comparing it with another similar species, M. elongatus (Yao & Yang, 1977). In this study, the types of both species were examined and also compared with several lots of specimens from a wide geographical range: there is no significant difference in morphology between them. Additionally, molecular evidence supported by mitochondrial gene sequence also showed low genetic distance in between. Thus, it is suggested that M. elongatus is a junior synonym of M. tungtingensis. While revising these two species, a new species, Microphysogobio punctatus sp. nov., was discovered that has a similar distribution with them both. However, it can be distinguished from its congeners by having a globular or oval shaped posterior air-bladder chamber which length 58.6%–82.8% of eye diameter; a narrow upper jaw cutting edge which less than half mouth width; a slender caudal peduncle with depth 34.6%–48.5% of length; and a six-branched-ray anal fin. This new species also has numerous small black spots on all fins which is also unique. The new species is morphologically and molecularly close to M. bicolor (Nichols, 1930).
Four new species of Georissa W. Blanford, 1864 (Gastropoda, Hydrocenidae) from Thailand
Authors: Klongklaew Kanyaporn , Poeaim Supattra , Dumrongrojwattana Pongrat
Published: October 2024

Hydrocenid snails have received little research attention compared to other land snail groups, arguably due to their small size. The present study examines the diversity of hydrocenid snails in limestone hills in central, eastern and southern Thailand. Four new species of Georissa W. Blanford, 1864 are described: G. quinqueliratasp. nov. from central Thailand, G. sagittasp. nov. and G. kohsichangensissp. nov. from eastern Thailand, and G. digitinotasp. nov. from southern Thailand. These four new species are distinguished by unique characteristics in their shell, including protoconch sculpture and shell shape, operculum, and radula morphology. A phylogenetic analysis of mitochondrial DNA sequences confirms the distinctiveness of all four species.
Nurses Filling the Gap
Authors: Doescher Terry
Published: October 2024

A gap analysis can be a valuable tool to identify and understand nursing practice deficiencies or gaps. Failure to find and fill gaps in skills, practices, or knowledge can affect patient outcomes. Nurses, nurse leaders, and health care providers can use a gap analysis to identify practice discrepancies that can affect patient care and outcomes. Conducting a gap analysis can guide the nurse to determine the best evidence-based practice solution for an issue or problem.

[
J Contin Educ Nurs.
2024;55(10):469–471.]
Artificial Intelligence in Skill Development
Authors: Bhowmick Mithun , Goswami Sourajyoti , Chakraborty Rideb , Bhowmick Pratibha , Nandy Souvik Kumar , Afrose Naureen , Kewatkar Shailesh M.
Published: October 2024

This chapter explores the impact of AI on professional development, education, and the pharmacy industry. AI systems enable creative language use without a computer, transforming traditional tutoring centers into iterative learning processes. AI tools also develop skills to new accessibility standards and cater to individual learner needs. In medicine and pharmaceutical industries, AI provides tailored learning paths, content delivery, and feedback through computer simulations. It also offers technology solutions for soft skills training, such as communication and leadership. However, the chapter addresses ethical questions and challenges, such as data privacy, de-biasing AI algorithms, and closing digital divides. The chapter provides insights for educators, healthcare workers, and technology practitioners on how to maximize AI's potential for comprehensive learning and skill development. The chapter aims to re-assess the potential of AI in the skills business for integration.
Unlocking Academic Success
Authors: Raghavendra A. N. , Halaswamy D. , Vijayakumar G. , Sandhya S.
Published: October 2024

Delving into the intersection of artificial intelligence (AI) and student anxiety management, this chapter determines a promising outlook for addressing a prevalent concern in education. By harnessing AI's capabilities to comprehend, evaluate, and alleviate anxiety, educators and mental health professionals stand to offer tailored and prompt support to students. A harmonious blend of AI technology with human empathy emerges as the key to fortifying student well-being, thereby fostering a more robust and productive academic community. With attitudes towards AI explaining a significant portion of anxiety management variance, educators and policymakers are urged to embed AI-related education and positive reinforcement within curricula, potentially amplifying students' mental wellness. Furthermore, this chapter unveils insights into the nuanced influence of gender, age, and prior technology exposure on the efficacy of AI in anxiety management. While gender emerges as a significant moderator, age does not, hinting at the importance of personalized approaches in AI interventions.
Financial Risk Early Warning Model Combining SMOTE and Random Forest for Internet Finance Companies
Authors: Zheng Zhongqin
Published: October 2024

At present, there have been many achievements on enterprise financial risk early warning model, but relatively few early warning studies focusing on the Internet industry. Research shows that the model has stable recognition accuracy and good prediction performance. The improved SMOTE algorithm based on PCA can realize the equalization of unbalanced data sets and use random forest as a classifier to classify and predict geological data. Because the noise data in the original data set may cause the change of the data distribution after interpolation, it is proposed to combine the PCA algorithm and the SMOTE algorithm, first perform noise reduction and dimension reduction, and then perform data interpolation to improve the classification performance of imbalanced data sets. my country's Internet financial listed companies conduct experiments on research samples, algorithm can better improve the classification accuracy and provide new ideas for the classification and prediction of unbalanced data.
A EDUCAÇÃO PELAS IMAGENS DO GLOBO TERRESTRE NA REVISTA NATIONAL GEOGRAPHIC
Authors: Tomelin Vanessa Pâmela , Chaves Ana Paula Nunes
Published: October 2024

Neste texto, colocamos em discussão imagens do globo terrestre disseminadas pela revista National Geographic no período de 1970 até 2021. Intentamos refletir sobre concepções de mundo oriundas de narrativas visuais sobre o Planeta visibilizadas pelas imagens presentes no periódico e pensar essas concepções para a educação geográfica. Com base nos aportes teóricos de Denis E. Cosgrove e Verónica C. Hollman, partimos do pressuposto que as concepções de mundo geradas pelas narrativas presentes nas imagens implicam na educação geográfica, pois nos educam visual, cultural e geograficamente. Para realizar a investigação, identificamos 2.201 imagens do globo terrestre no periódico, dentre elas, fotografias, imagens de satélite e diversos tipos de desenhos. Esse conjunto de imagens foi organizado em quatro frentes analíticas e, neste texto, apresentamos a que origina uma concepção de mundo como nosso lar no Universo. São 177 imagens dentre o total que se referem a Terra como o nosso lugar, e que o mostram como a) um lar único, em que há vida; b) um lar cercado por tecnologias e olhares artificiais; c) um lar que precisa de proteção, pois é frágil, vulnerável, finito em seus recursos. Observamos em tais concepções a perpetuação de conhecimentos sobre o Planeta já difundidos e sedimentados ao longo das últimas décadas e que o uso das imagens pode incentivar a reprodução de discursos dominantes sobre o mundo e o fortalecimento de narrativas hegemônicas.
“O começo, o meio e o começo”
Authors: Valdez Diane , Panizzolo Claudia , Dias Ana Raquel Costa , Rocha Juliano Guerra
Published: October 2024

Este artigo propõe debater aspectos de uma pesquisa interinstitucional, que resultou na produção do Dicionário de autoras(es) de cartilhas e livros de leitura no Brasil (século XIX), publicado em 2023 pela Editora Cegraf UFG. Objetivamos problematizar o uso da biografia na História da Educação, debatendo os caminhos metodológicos percorridos na constituição dos verbetes biográficos registrados nessa obra. Ao socializar os percursos para o desenvolvimento do Dicionário, apresentamos dados que explicitam os resultados e as lacunas da pesquisa, pretendendo garantir a divulgação das trajetórias de um projeto extenso, com as dificuldades próprias de uma produção que envolveu oitenta pesquisadoras(es) de várias regiões do Brasil e de Portugal.
Measurement and Characterization of Helicopter Noise at Different Altitudes
Authors:   US Army Aviation Development Division, Stephenson James ,   NASA Langley Research Center, Watts Michael , Greenwood Eric
Published: October 2024

This paper presents an overview of a flight test campaign performed at different test sites whose altitudes ranged from 0 to 7000 feet above mean sea level (AMSL) between September 2014 and February 2015. The purposes of this campaign were to: investigate the effects of altitude variation on noise generation, investigate the effects of gross weight variation on noise generation, establish the statistical variability in acoustic flight testing of helicopters, and characterize the effects of transient maneuvers on radiated noise for a medium-lift utility helicopter. In addition to describing the test campaign, results of the acoustic effects of altitude variation for the AS350 SD1 and EH-60L aircraft are presented. Large changes in acoustic amplitudes were observed in response to changes in ambient conditions when the helicopter was flown at constant indicated airspeed and gross weight at the three test sites. However, acoustic amplitudes were found to scale with ambient pressure when flight conditions were defined in terms of the non-dimensional parameters, such as the weight coefficient and effective hover tip Mach number.
Initial Development of a Quadcopter Simulation Environment for Auralization
Authors:   NASA Langley Research Center, Christian Andrew ,   Brigham Young University, Lawrence Joseph
Published: October 2024

This paper describes a recently created computer simulation of quadcopter flight dynamics for the NASA DELIVER project. The goal of this effort is to produce a simulation that includes a number of physical effects that are not usually found in other dynamics simulations (e.g., those used for flight controller development). These effects will be shown to have a significant impact on the fidelity of auralizations - entirely synthetic time-domain predictions of sound - based on this simulation when compared to a recording. High-fidelity auralizations are an important precursor to human subject tests that seek to understand the impact of vehicle configurations on noise and annoyance.
Detection And Analysis Of Interior And Exterior Noise Sources In A MD902 Helicopter
Authors:   Siemens PLM Software, Hallez Raphaël ,   MicrodB, Finez Arthur , Beebe Scott
Published: October 2024

Exterior helicopter noise is often perceived as loud and unpleasant by people boarding the helicopter or people living in urban areas or close to airports where rotorcraft is flying. Excessive cabin noise in the helicopter is also an issue for passengers or crew flying the helicopter, especially for long duration flights. The objective of the paper is to investigate commercially available techniques for measuring and analyzing helicopter noise and ultimately help design engineers get insight into noise mechanisms in view of potential noise improvements. Exterior noise measurements were performed on a MD902 helicopter equipped with a Notar (No TAil Rotor) system. State-of-theart focalization and deconvolution techniques are presented to localize and rank dominant noise sources and identify aeroacoustic phenomena or mechanical devices responsible for the helicopter noise signature. Primary and secondary sources are clearly identified which provides guidance for possible noise reduction measures. Main rotor noise is found to be clearly dominating the overall noise spectra whereas Notar, engine exhaust and cooling system constitute secondary sources. Interior noise is also investigated for various flight conditions and dominant noise sources are localized in the cabin and some possible noise control treatments are suggested. It is shown here that the acoustic array technique is a very efficient and well suited tool to analyze both interior and exterior helicopter noise.
Aerial Commuter Architecture Using Slung Loads
Authors:   Georgia Institute of Technology, Shukla Dhwanil , Hiremath Nandeesh , Komerath Narayanan
Published: October 2024

Evading traffic congestion by personal flying vehicle is still a far fetched dream. Recent advancements in predicting divergence speeds of slung loads using the Continuous Rotation Method (CRM) of airloads measurement has made is possible to obtain complete aerodynamic load maps of objects. In turn this enables on-the-fly system identification and dynamics predictions to ensure safety and smooth rides with slung loads. A concept is proposed for an air-lift service which can transport people with their personal road vehicles over congested areas. QFD and OEC analyses are used to compare different VTOL options for such a system. A pure conventional helicopter with internal or external carriage, a quadrotor, a lighter-than-air (LTA) platform with a quadrotor, and an LTA with cycloidal rotors are compared. The last two are found to be feasible, with only the LTA-cycloidal meeting all requirements when downwash and noise constraints are imposed. A streamlined carriage concept with aerodynamic control surfaces is suggested. A HUMVEE is used as an example where aerodynamic load mapping has been done, and the data used in predicting dynamics. This shows how to estimate the speed constraints to keep oscillations below specified levels, and verify the safety of the flight envelope.
Response Surface Estimation of Trim Controls for a Compound Helicopter with Control Redundancy
Authors:   Rensselaer Polytechnic Institute, Reddinger Jean-Paul , Gandhi Farhan
Published: October 2024

For a compound helicopter with sufficient control redundancy, this study presents a knowledge based method for estimating the set of controls required to maintain trim as a function of additional controls (main rotor RPM, auxiliary thrust, and stabilator pitch). Trim analyses with parametric sweeps through the additional controls are simulated in RCAS for a compound helicopter model based on a UH-60A. The resulting data sets are used to construct quadratic regression fit models, which represent the response of the six classical trim controls subject to variation in additional controls. In hover these models predict states that aren't fully trimmed, but the force and moment residuals are low. At forward flight speeds the response of the controls are no longer quadratic, and these force and moment residuals increase. Eliminating outlier trim states from the training data set gives the greatest improvement to the predictive capabilities of the model, but sacrifices some of the range of controls over which the model can apply. Kriging interpolation retains the full range of controls, but produces multiple local minima. For application to estimating the best controls for minimization of power it is shown that both truncating the data set and Kriging can provide good estimates of the minimum power trim state controls without excessive force and moment residuals. Allocating the additional controls as given by the response surfaces and solving for trim returned a slightly lower power than was found in the parametric trim sweeps.
Rotor Loads Prediction on the ONERA 7A Rotor using Loose Fluid/Structure Coupling
Authors:   ONERA - The French Aerospace Lab, Ortun Biel ,   US Army Aviation Development Directorate, Potsdam Mark , Truong Khiem , Yeo Hyeonsoo
Published: October 2024

This work exploits the ONERA 7A rotor wind tunnel test for comparison with concurrent simulations at the US Army and ONERA. Rotor airloads and structural loads are predicted by coupling Computational Fluid Dynamics (CFD) with rotorcraft comprehensive analysis (CA). Two test points are examined: a high-speed point and a high-thrust point featuring dynamic stall. The contributions of experimental data processing and wind tunnel test stand to improved agreement are shown. Comparisons are shown for airloads, structural loads, surface pressures, rotor controls and power. The use of state-of-the-art CFD/CA coupled tools provides dramatic improvements in agreement with experiment, compared to previous work. The Helios/RCAS coupling used by the US Army has been validated on the 7A rotor, adding to prior published validations on the UH-60A and HART-II rotors. The elsA/HOST coupling used by ONERA has had its latest developments validated as well.
Periodic Free Wake Simulation Using a Numerical Optimization Method
Authors:   Technische Universität München, Radler Simon , Hajek Manfred
Published: October 2024

A novel method has been developed for the free vortex wake simulation of rotors under the assumption of periodicity. An error measure is introduced which is based on the mismatch between prevailing convection velocities and the assumed wake element positions. The systematic reduction of this defined error results in a numerically robust method for the computation of wake geometries. Two strategies are compared for the error reduction. The first uses the repeated evaluation of the velocity field to update the wake geometry as long as the defined error decreases. In the second strategy, the application of a Levenberg-Marquardt method is added, in which the error is further reduced using an analytically defined Jacobian matrix. Results correlate well with experiments for single rotor and tandem rotor cases. While the Levenberg-Marquardt method achieves an additional error reduction, correlation with experimental data is not generally improved by including this method.
Influence Of The Diffuser Geometry Of Shrouded Rotors On The Aerodynamic Footprint Of MAVs
Authors:   ISAE-Supaéro, Ariza David , Jardin Thierry , Prothin Sebastien
Published: October 2024

Numerical simulations are conducted in order to assess the influence of diffuser geometry on the aerodynamic performance and aerodynamic footprint of shrouded rotors. The diffuser geometry varies in the azimuthal direction following a sine waveform with different wavelengths and amplitudes. It is shown that at a given rotor thrust, shroud thrust is reduced with respect to the optimized straight diffuser shape. For the specific cases addressed here, the reduction can simply be explained from simple potential flow theory / critical diffuser angle considerations as there is no clear evidence of strong induced three-dimensional effects. However, it is shown that wavy diffusers can help reduce the aerodynamic footprint of the rotor. This can potentially contribute to reducing brownout effects, thereby promoting flight capacity of MAVs operating in confined spaces through visual odometry.
A Summary of Flowfield Around a Rotor Blade in Reverse Flow
Authors:   Georgia Institute of Technology, Hiremath Nandeesh , Shukla Dhwanil , Raghav Vrishank , Komerath Narayanan
Published: October 2024

Prior work from our group presented 3-D velocity field measurements obtained using stereo particle image velocimetry (SPIV) under the sharp edge of a rotor blade in reverse flow. These showed the presence of a strong attached vortex reminiscent of that over a sharp-edged delta wing at angle of attack. The evolution of this sharp edge vortex (SEV) as the blade moves with decreasing yaw, dominates the aerodynamics of the blade in reverse flow. In this paper, we report new measurements that complete the picture. Data below the rotor blade, sufficiently resolved in space to permit interpolation to satisfy the continuity equation, enable extraction of the surface pressure field and the local circulation. This paper closes the loop and shows why a model of reversed flow rotor aerodynamics based on the formation and evolution of a strong sharp-edged vortex resolves several mysteries and provide a self-consistent explanation of observed phenomena. Further, logical argument shows that this test case is physically representative of what will be encountered on full-scale blades in flight.
A Hamiltonian-Strand Approach for Aerodynamic Flows Using Overset and Hybrid Meshes
Authors:   University of Maryland, Jung Yong , Govindarajan Bharath , Baeder James
Published: October 2024

A solution framework using Hamiltonian paths and strand grids (HAMSTR) is presented for three-dimensional flows on overset and hybrid meshes. The methodology creates a volume mesh starting from an unstructured surface mesh that can be comprised of mixed triangular-quadrilateral elements. "Linelets" through the meshes are found in a robust manner and the solver uses line-implicit schemes and high-order reconstruction schemes along these linelets, similar to a structured solver. The mesh system is also extended to utilize overset meshes. This overset technique allows for multiple mesh systems, which consists of a near-body Hamiltonian/Strand grid and off-body Cartesian nested meshes. The generalized approach to obtaining the Hamiltonian paths allows for initially structured and unstructured meshes to be quilted together to form a unified grid. In such cases, Hamiltonian paths can cross themselves; however, no changes are necessary for the flow solver. Finally, the integration framework between the various components of the code suite is performed using Python to allow for ease of integration in the future to other codes. Aerodynamic flows past an airfoil, sphere, wing and non-lifting rotor are presented using the Hamiltonian/Strand approach and good agreement was observed against experimental results as well as solutions obtained from traditional structured solvers.
Trimmed Simulation of a Complete Helicopter Configuration in Hover Flight
Authors:   KAIST, Park Se ,   Agency for Defense Development-ADD, Jang Ji , Chu Yeon , Lee Duck
Published: October 2024

Helicopter pilot needs persistent control to stay in hover because of main rotor wake-fuselage interaction as well as main rotor-tail rotor interaction. In the present research, the main rotor-tail rotor interference was examined with computation of the moment at the main rotor shaft and describing the wake structures of main rotor and tail rotor. It was confirmed that flapping response calculation is required in order to predict rotor aerodynamics accurately and achieve convergence of solution. Also, hover flight of complete helicopter configuration was simulated, and the required pilot control inputs were obtained through numerical trim process. The trimmed pilot input and predicted flapping angle were compared with analytic trim prediction result or flight test data. There needs to be further study to find the reason for deviation with flight test data.
Multi-Role Rotor - Adaptive Performance (MRRAP)
Authors:   The Boeing Company, Brouwers Edward ,   US Army Aviation Development Directorate, Centolanza Louis , Zientek Thomas , Cline Christopher , Bussom Richard , Straub Friedrich , Coffman Jeffery
Published: October 2024

The next generation of rotorcraft will require advanced rotor systems to deliver better performance and vibration characteristics. Rotor system design has always been one of compromise - traditionally between the hover and cruise regimes. It has long been recognized that the optimal geometry (twist, chord, sweep) for hover performance does not perform optimally in forward flight. In addition, optimizing the rotor design for hover can result in unintended consequences, such as increased vibration, that often accompanies suboptimal cruise performance. The long-sought benefit of an active rotor system is to adapt its geometry or its operation to mitigate the penalties in one regime or the other, expanding the design space afforded the designer. Although active rotor systems have been demonstrated in recent years, they have used primarily on-blade active devices, and the benefits have not addressed all of the next generation rotor goals.
The goal of the Multi-Role Rotor Technology Investment Agreement (TIA) between Boeing and the Army Aviation Development Directorate (ADD) is demonstrating technologies that avoid rotor design compromises in order to improve rotor performance and reduce vibration levels. The development of the innovative Multi-Role Rotor - Adaptive Performance (MRRAP) rotor promises the ability to truly adapt a blade to maximize hover and cruise efficiencies, while also incorporating control capabilities to reduce vibration.
Development of an Electro-Mechanical IBC Actuator
Authors:   The Boeing Company, Coffman Jeffrey ,   ThinGap LLC, Frank Evan ,   US Army, Centolanza Louis , Straub Friedrich , Birchette Terry , Bussom Rich
Published: October 2024

As part of the U.S. Army Aviation Development Directorate (ADD) sponsored Multi-Role Rotor - Adaptive Performance (MRRAP) program, Boeing explored a novel reconfigurable rotor concept that utilized two actuators to change blade twist and effect multi-cyclic blade pitch, respectively. Development activities included design studies for a 49-foot diameter rotor, fabrication and testing of full-scale components, and two wind tunnel tests. Testing on full scale key components, namely the torque tube used for blade twist and the actuator used for blade pitch, showed that the overall concept was feasible. Wind tunnel testing of Mach-scale rotors characterized the hover and cruise performance benefits of changing blade twist. The present paper addresses the development of an electro-mechanical actuator for multi-cyclic blade pitch control, including actuation requirements and trade studies of actuator/hub integration, and focusses on actuator design, fabrication, and testing. Results of the trade studies led to selection of electro-mechanical actuators using a rotary actuator integrated into the hub arm for quasi-static blade twist control (STC) and a linear actuator in place of the pitch link for individual blade control (IBC). This provided a compact and mechanically simple solution with no active components in the rotor blade. Design of the STC and IBC actuators was completed. The IBC actuator rate and duty cycle requirements were outside the normal design space and posed substantial thermal management and mechanical wear challenges. A Breadboard and improved Prototype IBC actuator were fabricated and tested. The development of the IBC actuator has shown that a high bandwidth actuator can be built with the capability to meet the stringent requirements. IBC actuator controller capability at high rates was proven during testing which was one of the key goals of this program. The roller screw design was capable of operating at the high frequency without load applied. The Prototype actuator was built as a development unit and has not been optimized. Further study on methods or design improvements to reduce the size and weight of the actuator and improve thermal management, as well as testing under load are recommended.
Leveraging Geometry Optimization Tools to Reduce Component Weight, Development Cost, and Design Schedule
Authors:   The Boeing Company, Bouwer Scott , Bowen David
Published: October 2024

Structural optimization tools such as OptiStruct enable design and stress engineers to visualize the most efficient load paths for a prescribed design space within the context of multiple load cases and boundary conditions. The main rotor gearbox (MRGB) team from the Sikorsky Boeing Joint Multi Role (JMR) SB>1 DEFIANT™ Aircraft leveraged these capabilities to streamline the development of complex gearbox housings. The benefits included more effective initial designs, reduced design / stress iterations and cycle time, and improved part weight performance. Based on experience from the JMR program, the practical application of optimization tools is discussed with a summary of advantages and limitations. In addition, several example applications from the SB>1 DEFIANT™ Aircraft MRGB are discussed in detail with an account of benefits observed and lessons learned.
525 Hydraulic System Optimization for Fly-By-Wire Control
Authors:   Bell Helicopter, Sobel James , Reynolds Robert
Published: October 2024

The Bell 525 is the world's first commercial helicopter to incorporate fly-by-wire flight controls. Fly-by-wire features will allow unparalleled safely and decreased pilot workload - especially for operation in austere environments. To support the unique requirements of a commercial fly-by-wire flight control system, the 525 design needed to incorporate three functionally identical, separate and continuously operating hydraulic systems. Any one system is independently capable of sustaining continued safe flight in the unlikely event that two systems become inoperative. The hydraulic system architecture incorporates complete system separation so that a hydraulic failure in one hydraulic system can not affect the other systems. To ensure that the flight control systems operate within required tolerances, thermal aspects of the three hydraulic systems are closely regulated. This unique Fly-by-wire architecture was optimized for weight, ease of aircraft manufacture/assembly, reliability, and field maintenance by using a technical approach that integrates system components to create rugged individual line replaceable units (LRU's). The integration concept was validated early in the 525 program by development testing of the components. This approach ensured that the aircraft build schedule would not be impacted by the hydraulic system design. Thermal design of the hydraulic system was optimized using Dynamic Physics based Amesim™ Hydraulic Systems Models to achieve weight targets of the hydraulic fluid conveyance system, and to fully validate the functional performance of the system. The sum total of these efforts led to an elegant 525 hydraulic system design which is successfully supporting 525 flight test activities.
Integrating Flight Dynamics & Control Analysis and Simulation in Rotorcraft Conceptual Design
Authors:   San Jose State University, Lawrence Ben ,   NASA, Theodore Colin ,   US Army, Berger Tom , Tobias Eric , Tischler Mark , Elmore Joshua , Gallaher Andrew
Published: October 2024

The development of a toolset, SIMPLI-FLYD ("SIMPLIfied FLight dynamics for conceptual Design") is described. SIMPLI-FLYD is a collection of tools that perform flight dynamics and control modeling and analysis of rotorcraft conceptual designs including a capability to evaluate the designs in an X-Plane-based real-time simulation. The establishment of this framework is now facilitating the exploration of this new capability, in terms of modeling fidelity and data requirements, and the investigation of which stability and control and handling qualities requirements are appropriate for conceptual design. Illustrative design variation studies for single main rotor and tiltrotor vehicle configurations show sensitivity of the stability and control characteristics and an approach to highlight potential weight savings by identifying over-design.
What are the Real Benefits of Applying Open Systems Architecture to Rotorcraft Mission Systems?
Authors:   The Boeing Company, Koontz Ronald
Published: October 2024

Software Open Systems Architecture (OSA) was first implemented on rotorcraft platform mission systems over 15 years ago. Mission systems OSA, similar to many other larger scale digital ecosystems OSA, continue to evolve to meet changing business needs. The dynamic and evolving nature of mission systems OSA is found to be consistent with observations and analyses of other large scale digital ecosystems. While multiple published papers describe the desired benefits in applying an OSA approach, this exploratory paper extends previous work by defining an approach for assessing the relative and realized benefits of a given OSA. A new technique for conducting architecture relative openness analysis is presented and then applied to a mission systems OSA. The new analysis technique compares a production rotorcraft OSA to conceptually open and closed architectures with consideration of business drivers and software ecosystems. This paper describes realized OSA benefits that are quantified by performing Quality Attribute (QA) cost / benefit analyses on fielded / production OSA products. Practical results from the fielded OSA cost / benefit analyses are also applied to OSAs that are currently being developed to support future Army rotorcraft programs. By applying the described new architecture comparative analysis technique, insight into actual OSA benefits and ecosystem dynamics can be more clearly understood and strategy for realizing additional future potential OSA benefits can be established. It is ultimately shown that the real benefit of a given OSA depends on how well it meets continuously evolving business and broader ecosystem stakeholder needs.
Airborne Integrated Voice, Data, and ADS-B in Compliance with the FAA and FCC
Authors:   Praxis Technologies Inc., Stanzione Kaydon
Published: October 2024

This paper addresses the design, development, and operations of a portable wireless airborne voice and data communication system that permits use of cell phones without violating the regulatory restrictions of the FCC or FAA. This same system also serves to integrate Automatic Dependent Surveillance - Broadcast (ADS-B) information into a single interoperable solution for improved situational awareness and command and control using commercially available edge devices such as smart phones and tablets. The Airborne Communication Platform™ (ACP), an optional enhancement to the Airborne Flight Reporting System™ (AFRS), provides an affordable, yet robust and FAA and FCC-compliant "black box" for a wide range of real-time voice and data communications between air and ground assets. Through a combination of multi-modal radios and programmable cellular frequencies, both voice telephony and data telemetry are possible using commercial-grade cell phones switched to "Airplane Mode." This enables voice and data communications outside of the restricted frequency range stipulated by either FAA or FCC for aircraft operations. Advantages include sending real-time flight performance, ADS-B information, and systems health and usage data while simultaneously permitting global voice communications on the ground and enroute at any altitude.
Testing Mobile Aircrew Restraint Systems in a Full-Scale CH-46 Airframe Crash Test - Exploring the Limits
Authors:   Naval Air Warfare Center Aircraft Division, Bark Lindley
Published: October 2024

The second of two full-scale crash tests of USMC CH-46 helicopter airframes was conducted at NASA-Langley Research Center. One of the internal experiments was an expanded assessment of a mobile aircrew restraint system (MARS) coupled with the Aircrew Endurance vest. Two Hybrid III Pedestrian Anthropomorphic Test Devices (ATDs) were positioned in a standing position, just aft of the crew door. On the port side, the ATD was positioned substantially close to structure on the aft side of the cockpit bulkhead with the objective to determine if the MARS could prevent contact between the ATD and structure. On the starboard side, the ATD was positioned underneath and inboard of the respective MARS reel and oriented to be aft-facing. The objective of both configurations was to assess the ability of the MARS to restrain occupants in challenging conditions and to limit injury potential. For the conditions evaluated, both MARS performed better than the gunner's belt results of the first CH-46 airframe crash test (Reference 1). This second crash test did illuminate a neck injury criterion exceedance for the port ATD that is likely caused by a non-standard helmet attachment to the ATD, but should be further investigated in a laboratory.
Evaluation of Aircrew Noise Exposure Levels on a Canadian CH-147F Chinook Helicopter
Authors:   National Research Council, Price Andrew , Ghinet Sebastian , Chen Yong , Wickramasinghe Viresh , Grewal Anant
Published: October 2024

The cabin and cockpit noise levels of a Royal Canadian Air Force CH-147F Chinook medium to heavy lift utility helicopter were evaluated in this study. The sound pressure levels were measured at nine aircrew locations through 43 unique and representative flight and ground conditions in accordance with the ISO 5129:2001 standard. Additionally, the performance of a combination of currently in service helmets and headsets were evaluated in accordance with the ANSI Standard S12.42. The hearing protection performance results were used in combination with the measured sound pressure levels to evaluate the performance of the hearing protection in the context of the CH-147F noise environment. Results showed that the David Clark headsets equipped with active noise reduction provided the most superior hearing protection. The maximum exposure limit duration was calculated for each microphone location, hearing protector performance and flight condition combination. It was found that the David Clark headsets provided sufficient protection for an unlimited duration of exposure for an individual with a properly fitted headset. It was also found that improperly fitted hearing protection could result in an increased risk of hearing damage after merely 18 seconds.
Performance and Loads of a Model Coaxial Rotor Part I: Wind Tunnel Measurements
Authors:   The University of Texas at Austin, Cameron Christopher , Sirohi Jayant
Published: October 2024

The results of wind tunnel tests of a model scale, closely spaced, rigid, counter-rotating coaxial rotor system are presented. The system, tested in the Glenn L. Martin wind tunnel, features-two bladed upper and lower rotors, 2.03m in diameter, with uniform section, untwisted rotor blades. Measurements include upper and lower rotor steady and vibratory hub loads, control angles and loads. Blade tip clearance was measured using a custom optical sensor. The rotor system was tested at advance ratios between 0.21 and 0.53, at collective pitches ranging from 2 to 10 degrees achieving blade loadings in excess of 0.10. Sweeps of lift offset up to 20% were performed at each operating condition, with a limited test matrix for variation in rotor speed and inter-rotor phase angle variation. Rotor effective lift-to-drag ratio was found to increase with increasing advance ratio and lift offset resulting in a 30% peak efficiency gain. The lower coaxial rotor was found to operate at higher lift-to-drag ratio than the upper rotor due to aerodynamic interference. Lift offset results in a decrease in blade tip clearance with a corresponding rise in rotor side force. Vibratory loads increase with advance ratio with the largest loads in the two and four-per-revolution harmonics. The coaxial rotor system experiences lower vibratory in-plane forces and torque than the isolated rotors due to cancellation between upper and lower rotor load harmonics. Lift offset, in conjunction with inter-rotor phase angle is shown to modify two-per-revolution in-plane vibratory forces and moments transmitted to the fixed frame, increasing some force components while decreasing others.