bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE OF COLLABORATIVE RELATIONSHIPS ON THE PERFORMANCE OF DESIGN-CONSTRUCTION EFFICIENCY OF INDUSTRIALIZED CONSTRUCTION
Authors: Daget Yidnekachew Tesmamma , Zhang Hong
Published: April 2023

The poor collaboration among the main actors in the construction has become a challenge for the low performance of the design-construction efficiency (DCE). This study investigated and quantitatively evaluated the influence of network relationships in stakeholders’ collaborative management (SCM) and their effect on the performance of the DCE of industrialized construction projects. Hypotheses were proposed and tested. Based on multiple empirical cases, semistructured interviews and questionnaire surveys were conducted. Social network analysis (SNA) was adopted as a research technique for graphical analysis and quantitative evaluation of the SCM. The study’s findings revealed that the different sets and modes of collaboration directly impacted the performance of the DCE of industrialized construction. Further findings showed that strong collaboration among the contractors, designers, and manufacturers significantly impacts achieving better efficiency. Meanwhile, DCE was the most important driving factor for the SCM. The network relationships had a positive impact on the DCE. The study contributes knowledge in demonstrating the application of network relationships in industrialized construction research and helps practitioners establish a strong SCM to improve the efficiency of industrialized construction in a wider global context.
The SSA22 H i Tomography Survey (SSA22-HIT). I. Data Set and Compiled Redshift Catalog
Authors: Mawatari Ken , Inoue Akio K. , Yamada Toru , Hayashino Tomoki , Prochaska J. Xavier , Lee Khee-Gan , Tejos Nicolas , Kashikawa Nobunari , Otsuka Takuya , Yamanaka Satoshi , Schlegel David J. , Matsuda Yuichi , Hennawi Joseph F. , Iwata Ikuru , Umehata Hideki , Mukae Shiro , Ouchi Masami , Sugahara Yuma , Tamura Yoichi
Published: April 2023

We conducted a deep spectroscopic survey, named SSA22-HIT, in the SSA22 field with the DEep Imaging MultiObject Spectrograph (DEIMOS) on the Keck telescope, designed to tomographically map high-z H i gas through analysis of Lyα absorption in background galaxies’ spectra. In total, 198 galaxies were spectroscopically confirmed at 2.5 < z < 6 with a few low-z exceptions in the 26 × 15 arcmin2 area, of which 148 were newly determined in this study. Our redshift measurements were merged with previously confirmed redshifts available in the 34 × 27 arcmin2 area of the SSA22 field. This compiled catalog containing 730 galaxies of various types at z > 2 is useful for various applications, and it is made publicly available. Our SSA22-HIT survey has increased by approximately twice the number of spectroscopic redshifts of sources at z > 3.2 in the observed field. From a comparison with publicly available redshift catalogs, we show that our compiled redshift catalog in the SSA22 field is comparable to those among major extragalactic survey fields in terms of a combination of wide area and high surface number density of objects at z > 2. About 40% of the spectroscopically confirmed objects in SSA22-HIT show reasonable quality of spectra in the wavelengths shorter than Lyα when a sufficient amount of smoothing is adopted. Our data set enables us to make the H i tomographic map at z ≳ 3, which we present in a parallel study.
Detection of Dipole Modulation in CMB Temperature Anisotropy Maps from WMAP and Planck using Artificial Intelligence
Authors: Khan Md Ishaque , Saha Rajib
Published: April 2023

Breakdown of rotational invariance of the primordial power spectrum manifests in the statistical anisotropy of the observed Cosmic Microwave Background (CMB) radiation. Hemispherical power asymmetry in the CMB may be caused due to a dipolar modulation, indicating the presence of a preferred direction. Appropriately rescaled local variance maps of the CMB temperature anisotropy data effectively encapsulate this dipolar pattern. As a first-of-its-kind method, we train Artificial Neural Networks (ANNs) with such local variances as input features to distinguish statistically isotropic CMB maps from dipole-modulated ones. Our trained ANNs are able to predict components of the amplitude times the unit vector of the preferred direction for mixed sets of modulated and unmodulated maps, with goodness-of-fit (R
2) scores >0.97 for full sky and >0.96 for partial sky coverage. On all observed foreground-cleaned CMB maps, the ANNs detect the dipolar modulation signal with overall consistent values of amplitudes and directions. This detection is significant at 97.21%–99.38% C.L. for all full sky maps, and at 98.34%–100% C.L. for all partial sky maps. Robustness of the signal holds across full and partial skies, various foreground cleaning methods, inpainting algorithms, instruments, and all the different periods of observation for Planck and WMAP satellites. The significant and robust detection of the signal, in addition to the consistency of values of amplitude and directions, as found independent of any preexisting methods, further mitigates the criticisms of look-elsewhere effects and a posteriori inferences for the preferred dipole direction in the CMB.
The Black Hole Candidate Swift J1728.9–3613 and the Supernova Remnant G351.9–0.9
Authors: Balakrishnan Mayura , Draghis Paul A. , Miller Jon M. , Bright Joe , Fender Robert , Ng Mason , Cackett Edward , Fabian Andrew , Kuntz Kip , Miller-Jones James C. A. , Proga Daniel , Ray Paul S. , Raymond John , Reynolds Mark , Zoghbi Abderahmen
Published: April 2023

A number of neutron stars have been observed within the remnants of the core-collapse supernova explosions that created them. In contrast, black holes are not yet clearly associated with supernova remnants (SNRs). Indeed, some observations suggest that black holes are “born in the dark,” i.e., without a supernova explosion. Herein, we present a multiwavelength analysis of the X-ray transient Swift J1728.9−3613, based on observations made with Chandra, ESO-VISTA, MeerKAT, NICER, NuSTAR, Swift, and XMM-Newton. Three independent diagnostics indicate that the system likely harbors a black hole primary. Infrared imaging signals a massive companion star that is broadly consistent with an A or B spectral type. Most importantly, the X-ray binary lies within the central region of the cataloged SNR G351.9−0.9. Our deep MeerKAT image at 1.28 GHz signals that the remnant is in the Sedov phase; this fact and the nondetection of the soft X-ray emission expected from such a remnant argue that it lies at a distance that could coincide with the black hole. Utilizing a formal measurement of the distance to Swift J1728.9−3613 (d = 8.4 ± 0.8 kpc), a lower limit on the distance to G351.9−0.9 (d ≥ 7.5 kpc), and the number and distribution of black holes and SNRs within the Milky Way, extensive simulations suggest that the probability of a chance superposition is <1.7% (99.7% credible interval). The discovery of a black hole within an SNR would support numerical simulations that produce black holes and remnants, and thus provide clear observational evidence of distinct black hole formation channels. We discuss the robustness of our analysis and some challenges to this interpretation.
Parallelization of the Symplectic Massive Body Algorithm (SyMBA) N-body Code
Authors: Lau Tommy Chi Ho , Lee Man Hoi
Published: April 2023

Direct N-body simulations of a large number of particles, especially in the study of planetesimal dynamics and planet formation, have been computationally challenging even with modern machines. This work presents the combination of fully parallelized N
2/2 interactions and the incorporation of the GENGA code’s close encounter pair grouping strategy to enable MIMD parallelization of the Symplectic Massive Body Algorithm (SyMBA) with OpenMP on multi-core CPUs in shared-memory environment. SyMBAp (SyMBA parallelized) preserves the symplectic nature of SyMBA and shows good scalability, with a speedup of 30.8 times with 56 cores in a simulation with 5000 fully interactive particles.
A Speckle Search for the Outer Companion of KIC 9832227
Authors: Salinas Ricardo , Howell Steve B.
Published: April 2023

We present Gemini-N/’Alopeke speckle observations of KIC 9832227, a system originally predicted to become a red nova. The diffraction limited observations do not find an outer companion between 11 and 678 au that could be responsible for the period changes of the system.
Braconid imagobionts from the tribe Cosmophorini (Hymenoptera, Braconidae, Euphorinae) in the fauna of South Korea
Authors: Belokobylskij Sergey A. , Ku Deokseo
Published: April 2023

Two euphorine taxa from the tribe Cosmophorini, the genus Cryptoxilos Viereck, 1911 and the subgenus Eucosmophorus Belokobylskij, 2000 (genus Cosmophorus Ratzeburg, 1848) are recorded for the first time for the Korean Peninsula. Three species from South Korea, Cosmophorus (Eucosmophorus) jejuensissp. nov., C. (Eu.) wandoensissp. nov., and Cryptoxilos (Cryptoxiloides) ulleungussp. nov., are described and illustrated. Keys to the described species of Cosmophorus (Eucosmophorus) and Cryptoxilos (Cryptoxiloides) are provided. Digital photographs of the type species of the subgenus Eucosmophorus, Cosmophorus undulatus Belokobylskij, 2000, are published for the first time.
1990-2000 : une autre réception française de Leo Strauss
Authors: Smadja David
Published: April 2023

À travers la réalisation et le commentaire de deux entretiens approfondis avec Corinne Pelluchon et Daniel Tanguay, l’article décrit un autre mode de réappropriation de Leo Strauss, distinct des premières réceptions françaises assurées par Raymond Aron et Alexandre Kojève . Il fait apparaître un cadrage du philosophe différent de celui de ses contemporains. Si les deux enquêtés manifestent des dispositions théoricopratiques qui les conduisent à replacer au premier plan le problème théologicopolitique de Strauss, ce cadrage répond chez eux davantage à un intérêt d’ordre historique, orienté vers l’établissement et la traduction d’un corpus , qu’à la poursuite d’objectifs idéologiques ou politiques.
La « Drôle de pensée » (1675)
Authors: Rateau Paul
Published: April 2023

Dans la « Drôle de pensée touchant une nouvelle sorte de représentations », rédigée à Paris en septembre 1675, Leibniz envisage de transformer la capitale française en un grand musée des savoirs, des arts et des métiers. Il rêve d’en faire un gigantesque lieu d’exposition des connaissances et des inventions, un laboratoire d’expérimentations, où seraient également donnés spectacles, jeux et divertissements. Le texte a été écrit à la suite de la représentation d’une machine servant à marcher sur l’eau, à laquelle a assisté le philosophe. En identifiant cette machine à une lanquerre, l’article propose de réinterpréter le contenu et le but du projet esquissé dans la « Drôle de pensée ».
Hegel et l’idée d’une logique spéculative
Authors: Fraisopi Fausto
Published: April 2023

Dans cette première partie de questionnement de l’idée de logique spéculative chez Hegel, on retrace tout d’abord l’idée d’élément logique ou du « logique » ( das Logiche ) chez Hegel. Cela converge vers un questionnement de l’origine du spéculatif à la fois dans l’histoire de la pensée occidentale (tant chez les Grecs que chez Augustin) et dans la pensée kantienne, qui sert de base (critique) pour l’élaboration de l’idée de logique spéculative. Cette double approche sert de description d’un horizon général et problématique au sein duquel insérer l’approche des différentes « dialectiques » de la logique hégélienne.
Non-parametric accelerated life testing estimation for fuzzy life times under fuzzy stress levels
Authors: Shafiq Muhammad , Shah Syed Habib , Abiad Mohammad , Zaman Qamruz
Published: April 2023

Uncompleted developments in the fields of measurement sciences are categorically agreed on the fact that measurements obtained from continuous phenomena cannot be measured precisely. Therefore, these measurements cannot be considered precise numbers but are nonprecise or fuzzy. For this purpose, it is compulsion of the time that such estimators need to be developed to cover both the uncertainties. The classical accelerated life testing (ALT) approaches are based on precise life times and precise stress levels, but in fact, these are not precise numbers but fuzzy. In this study, the nonparametric procedure of ALT is generalized in such a manner that in addition to random variation, fuzziness of the lifetime observations and stress levels are integrated in the developed estimators. The developed generalized nonparametric estimators for accelerated life time analysis utilize all the obtainable information that is present in the form of fuzziness in single observations and random variation among the observations to make suitable inferences. On the other hand, classical estimators only deal with random variation, which is a strong reason to conclude that the developed estimators should be preferred over classical estimators.
Study of optimal vaccination strategies for early COVID-19 pandemic using an age-structured mathematical model: A case study of the USA
Authors: Luebben Giulia , González-Parra Gilberto , Cervantes Bishop
Published: April 2023

In this paper we study different vaccination strategies that could have been implemented for the early COVID-19 pandemic. We use a demographic epidemiological mathematical model based on differential equations in order to investigate the efficacy of a variety of vaccination strategies under limited vaccine supply. We use the number of deaths as the metric to measure the efficacy of each of these strategies. Finding the optimal strategy for the vaccination programs is a complex problem due to the large number of variables that affect the outcomes. The constructed mathematical model takes into account demographic risk factors such as age, comorbidity status and social contacts of the population. We perform simulations to assess the performance of more than three million vaccination strategies which vary depending on the vaccine priority of each group. This study focuses on the scenario corresponding to the early vaccination period in the USA, but can be extended to other countries. The results of this study show the importance of designing an optimal vaccination strategy in order to save human lives. The problem is extremely complex due to the large amount of factors, high dimensionality and nonlinearities. We found that for low/moderate transmission rates the optimal strategy prioritizes high transmission groups, but for high transmission rates, the optimal strategy focuses on groups with high CFRs. The results provide valuable information for the design of optimal vaccination programs. Moreover, the results help to design scientific vaccination guidelines for future pandemics.
Emancipatory Attention
Authors: Mole Christopher
Published: April 2023

The aim of this paper is to show that, for the purposes of addressing the epistemic aspects of systemic injustice, we need a notion of emancipatory attention.  When the epistemic and ethical elements of an injustice are intertwined, it is a misleading idealisation to think of these epistemological elements as calling for the promotion of knowledge through a rational dialectic.  Taking them to instead call for a campaign of consciousness-raising runs into difficulties of its own, when negotiating the twin risks of being presumptuous about one’s own ignorance, and patronising in attributing ignorance to others.  To arrive at a better response, we should follow Marilyn Frye’s suggestion that the epistemic aspects of injustice are, at root, problems of attention.  But we fail to give an adequate account of this if we adhere to the most influential tradition of thinking about attention’s ethics, which takes its lead from Iris Murdoch’s reading of Simone Weil.  That tradition addresses attention’s significance in individual contexts, rather than social ones.  To get a better conception of the role that is played by attention in projects of social emancipation, we should take some ideas from recent work on the metaphysics of attention, together with ideas from an older tradition – represented here by R.G. Collingwood’s The Principles of Art – concerning the forms of attention that are occasioned by the creation and appreciation of art. 
Artificial Neural Networks
Authors: Pires Paulo Botelho , Santos José Duarte , Pereira Inês Veiga
Published: April 2023

This chapter contains a description of the historical evolution of artificial neural networks since their inception, with the appearance of the first relevant learning method by Paul Werbos in 1986, which remained ignored until it was discovered simultaneously by three groups of independent researchers: LeCun (1986); Parker (1985); and Rumelhart, Hinton, and Williams (1986). The basic concepts and definitions are also described, followed by the different typologies and the most relevant learning algorithms, most notably the backpropagation algorithm. The most recent advances in artificial neural networks are also described, highlighting convolutional neural networks and deep learning.
Exploring the Integration of ICT in Public Sector Management in Namibia
Authors: Mbangula Daniel Kwalipo
Published: April 2023

This study explored how Namibia's public sector management is impacted by information and communication technologies (ICT). Information technology is currently undergoing significant change, beginning with the impact it is having on public sector employees' attendance at training sessions so they can learn new skills like using IT developments, gaining new knowledge, skills, and utilizing programs in various fields where more productive and profitable results are obtained. Therefore, it is the responsibility of the public sector, civil society, and international actors to work together to develop the policies and programs that will fully realize the potential of digital government for Namibia's public sector at all levels.
Using VR for Collaborative Learning
Authors: Spike Jonathan , Xie Ying
Published: April 2023

Although virtual reality (VR) has been technologically possible for decades, both logistical and pedagogical limitations have slowed progress relating to collaborating with others in virtual reality environments. This article establishes a working framework, namely embodied social translucence, to illustrate VR-based collaborative learning through the theories of social translucence and embodied cognition. To help contextualize VR tools' abilities to facilitate collaborative learning, the authors analyze collaborative virtual reality studies and evaluate three current virtual reality platforms in terms of collaborative potential. They also provide recommended best practices for facilitating and designing collaborative virtual reality learning experiences.
CLEPTOHERBÁRIO E EXPERIMENTAÇÃO: FERRAMENTAS EM UMA SEI PARA ENSINAR BOTÂNICA
Authors: Porto Andréia , De Oliveira Patrícia Carla
Published: April 2023

Muitos docentes permanecem na constância do método único de ensino (aula expositiva) e, em geral, os estudantes costumam ter dificuldades para assimilar os conteúdos, pois alegam que os termos utilizados são muito complicados, difíceis de serem escritos e pronunciados. Esse trabalho é uma pesquisa quanti-qualitativa que teve como objetivo criar, aplicar, avaliar e divulgar uma sequência de ensino investigativo que poderá ser utilizada por outros docentes nas aulas de Botânica sobre morfologias das angiospermas. A proposta foi aplicada de forma remota com 23 estudantes do 2o ano do Ensino Médio de uma escola pública estadual localizada no município de Campo Verde-MT, entre os meses de maio e junho de 2021. A SEI aqui apresentada está organizada em seis etapas: problematização, experimentação, base teórica, descrição, exsicatas e cleptoherbário. Cleptoherbário é um termo informal que foi utilizado para se referir a um tipo de herbário portátil, o qual se configurou como ferramenta de ensino e avaliação, visto que esta deve acompanhar o processo de ensino e aprendizagem. Para participar dessa pesquisa, os estudantes receberam um guia impresso, um kit para experimentação e um livro de Biologia. Os dados foram coletados por meio dos guias que foram devolvidos na escola e das informações postadas no grupo do WhatsApp, bem como durante a comunicação síncrona no Google Classroom. Os resultados apontam que essa SEI possui boa aplicabilidade e permite aplicar o ensino investigativo nas aulas de Botânica, tornando, assim, o processo de ensino e aprendizagem muito mais dinâmicos e atraente para estudantes e docentes.
Strengthening of a Damaged Concrete Structure - Case Study of an Eleven Stories Building in Dar es Salaam
Authors: Makunza John K.
Published: April 2023

Concrete structures may become obsolete and be unfit for use to the extent that they need special attendance of repair or strengthening so as to revive them. The weakness in the buildings may be caused by natural disasters like earthquake, floods, changes of use of the buildings in which higher loads more than the design loads, e.g. vertical extension loads, are applied. When the structures are defective they need to be strengthened in order to restore their original structural integrity. Sometimes, the defect or deterioration needs to be scientifically analysed first in order to know the root cause of the problem and apply the right corrective measures. A case study on an eleven stories damaged building in is presented, starting with an investigation on causes of sudden crushing of one column and a strengthening method which embraced a number of techniques such as Land Surveying and non-destructive tests in assessing the building structural integrity. The crushed column and other columns is the ground floor were all strengthened using jacketing method and provision of additional columns at the crushed column. Keywords: Columns, crushing, non-destructive tests, concrete quality, deflection, plumb, jacketing, strengthening
FTIR Study of Enriched Bituminous Ukhaa-Khudag Coal
Authors: Sambuu Munkhtsetseg , Renten Nyamdulam , Tumendemberel Begzsuren , Tschaggelar Rene , Oleshkevich Anna , Tuvdendor Otgonchimeg , Sharav Munkhjargal , Goolimensee Shilagardi
Published: April 2023

In the present work we pay an attention to the molecular structural changes between raw coal and its enriched, dense productions. Bituminous Ukhaa-Khudag coal in the form of an enriched, dense coal product is currently used as an energy source by Mongolian consumers for everyday need. There are three types of samples from one source: it is a raw coal (sample 1) and two of industrial prod- ucts as an enriched, dopant (organic based) added coal (sample 2) and simply enriched coal (sample 3). The raw coal general characterization is given through the elemental analysis, thermogravimetry analysis, moreover functional groups were identified by Fourier Transform infrared spectroscopy. The differences in the FTIR spectra of the samples were done.Some details are as follows: hydroxyl group vibrations are existing, rather weak in agreement of TG result; vibrations of aliphatic group were rarely in the long wave near region, carbonate minerals in the region of 1300-900 cm−1 are visible but overlapped, and an isolated out-of-plane deformational vibration (around 800 cm−1) or two-adjacent (800-750 cm−1) or three-adjacent (around 700 cm−1) of sp2-hybrid bonded aromatic CHx-groups were still presenting.After the processing hydroxyl group bands were affected in enriched coals, sample 2 and 3. In the spectrum of the sample 2 the long wave bands were intensively blurred.Industry processing retains an amount of water in the productions. Water excess influenced absorbance bands were able to be removed via the drying processing, however, the affection to the spectral struc- ture in sample 2 was unrecoverable.
IoT-Based Real Time pH Monitoring of University of Mindanao’s Chemical Laboratory Wastewater
Authors: Morales Egi Joe Fran , Lawagon Chosel P.
Published: April 2023

Wastewater is a by-product of industrial and commercial facilities. If not treated, it could cause environmental and health problems. The proposed IoT-Based Real-Time pH Monitoring of wastewater can regulate the disposed waste through web browsers. The device has undergone several trials with wastewater from the chemical laboratory at different pH levels. It gave the signal to the solenoid motor to position either close when the pH level is more significant than pH 7.5 and less than pH 6.5 or open when the pH level is pH 6.5 to pH 7.5. The output's accuracy was measured using buffer solutions at different temperatures. It showed that the value of the pH level varied in temperature with significantly small changes. The system monitoring in the web browser captured the data every minute and saved it in a database for data comparison purposes. The device conformed to the Department of Environmental Natural Resources - Environmental Management Bureau (DENR-EMB) in the Philippines' standard permissible pH level (pH 6.0 to pH 9.0). Using an Arduino NANO microcontroller that served as a central processing unit and a Node MCU to connect the system to the internet, the equivalent output of an industrial pH meter was obtained, allowing the user to monitor the system at any time using a web browser.
Height-Velocity Characteristics Comparisons of Single-rotor and Coaxial Helicopters
Authors:   Nanjing University of Aeronautics and Astronautics, Zhao Yanqin , Chen Renliang , Yu Xin
Published: April 2023

The one-engine-inoperative(OEI) Height-Velocity characteristic differences of three rotorcraft configurations, including conventional helicopter, coaxial helicopter and coaxial compound helicopter, are investigated and compared. Equivalent flight dynamic models are established as per corresponding configuration, and the level flight trim results are given for preliminary difference analysis from aspects of power, control and attitude angle under the same hover power of rotors. Following this, the optimal control method for H-V diagram and landing procedure prediction is described. From the perspective of energy conservation, the comparisons including H-V diagrams and optimal trajectories at three key points (the low hover, high hover and knee) are presented and explained. Results indicate that coaxial configuration is of better landing performance than an equivalent single-rotor helicopter, resulting from its better aerodynamic efficiency and maneuverability. Under the same hover power of rotor, its area of H-V diagram is about one-fourth of the latter. On the other hand, the H-V diagrams of two coaxial are similar except smaller knee-point speed of the one with propeller. As for the operation of the propeller during landing, optimal results shows that the thrust generated from the propeller declines and stays at the low boundary to maximize power provided for main rotor.
Air Launched Effects Payload and Air Vehicle Integration
Authors:   Elbit Systems of America, Lengyel J. ,   Areo I Inc., Sosa Patrick
Published: April 2023

This paper is applicable to the Vertical Flight Society Operations Sessions and chronicles the development and testing of an Air Launched Effect (ALE) payload to Detect, Identify, Locate and Report (DILR) the whereabouts of a radio frequency (RF) emitter such as an enemy RADAR. During operations the DILR Effect helps provide safe passage for troops and assets in highly contested air space. The capability development activity, including field trials, was a collaborative effort amongst the U. S. Army Combat Capabilities Development Command Aviation and Missile Center (AvMC) who provided the test site and all necessary personnel and assets, Area I who provided the Unmanned Aerial System (UAS), data link and controller used in the flight trials and Elbit America who developed the DILR payload, algorithms, data analytics and control commands. The objective is to demonstrate rapid discovery and geolocation of an embedded field emitter in an unknown location within an acceptable error margin and high confidence level.
Linear Model Identification for Rotorcraft Using Adaptive Learning
Authors:   Aerotim Engineering LLC, Gursoy Gonenc ,   Middle East Technical University, Aslandogan Ongun , Yavrucuk Ilkay
Published: April 2023

Convergence to a unique identification result with an optimum model structure is a goal in rotorcraft system identification. Whether using time domain or frequency domain methods, achievement of this target requires additional tools, startup procedures/algorithms or a-priori information about the plant. In this paper, an adaptive learning based methodology is proposed to improve parameter convergence. The bounded convergence is guaranteed and robust to initial conditions even when there exist redundant derivatives in the initial state-space structure. A converged solution is obtained as a starting point and a typical bias-variance trade-off is performed. The effectiveness of the method is demonstrated through the identification of a Level-D class high-fidelity nonlinear helicopter model. The converged solution and the reduced order model can also be used in other system identification methods/algorithms as a starting identification state.
Linear Time-Invariant Models of Rotorcraft Flight Dynamics, Vibrations, and Acoustics
Authors:   Georgia Institute of Technology, Saetti Umberto ,   Pennsylvania State University, Brentner Kenneth , Horn Joseph
Published: April 2023

The paper discusses the development of a novel linearization algorithm to obtain high-order linear time-invariant (LTI) models of the coupled rotorcraft flight dynamics, vibrations, and acoustics. To demonstrate the methodology, the study makes use a nonlinear simulation model of a generic utility helicopter (PSU-HeloSim) that is coupled with an aeroacoustic solver based on a marching cubes algorithm. First, a revisited harmonic balance algorithm based on harmonic decomposition is applied to find the periodic equilibrium and approximate high-order LTI dynamics at 80 kts level flight. Next, the proposed output linearization scheme is applied to derive time-invariant, linearized equations of the main rotor forces and moments, and acoustics. Simulations are used to validate the response of the linearized models against that from nonlinear simulations. Additionally, the cost of linearization and potential performance benefits of employing linear models versus nonlinear simulations are assessed. The high-order LTI models thus obtained are shown to provide similar acoustic predictions compared to those of nonlinear simulations for small amplitude maneuvers, but at a fraction of the computational cost. These linear simulations are shown to run in the order of thousands of times faster than real time, and four orders of magnitude faster than nonlinear acoustic predictions based on a marching cubes algorithm.
Multi-physics Predictive Modeling Platform for Qualification of Material Microstructure and Mechanical Performance of Aerospace Additive Manufacturing Parts
Authors:   Sentient Science, Jalalahmadi Behrooz , Rios Jason
Published: April 2023

Sentient has developed a predictive modeling tool for components built using AM to assess their performance, with rigorous consideration of the microstructural properties governing the nucleation and propagation of fatigue cracks. This tool, called DigitalClone® for Additive Manufacturing (DCAM), is an Integrated Computational Materials Engineering (ICME) tool that includes models of crack initiation and damage progression with the high-fidelity process and microstructure modeling approaches. The predictive model has three main modules: process modeling, microstructure modeling, and fatigue modeling. The feasibility and validation of our modeling tool is verified using experimental coupon testing. The predictive tool is able to account for temperature and microstructure variation as the function of process parameters and scanning strategies at various AM processes. The relationship of processmicrostructure in additive manufacturing is successfully linked implicitly in our tool. We simulate the AM build process considering the parameters (laser intensity, laser speed, hatching space, powder layer thickness, orientation of build, etc.) involved during the build process in order to generate the microstructure of AM part which is the outcome of the build process. There is a good agreement between our prediction and the experimental data. The physics-based computational modeling encompassed within DCAM provides an efficient capability to fully explore the design space across geometries and materials, leading to components that represent the optimal combination of performance, reliability, and durability.
Mission Performance and Cost Calculation for variable Rotor Speed Drivetrain
Authors:   Zoerkler Gears, Amri Hanns , Auer Andreas , Gross Christpoher
Published: April 2023

The research presented in this paper is part of the international research project VARI-SPEED, which aims to invent a mass optimized speed variable drivetrain comprising a main gearbox with variable transmission ratio and a rotor suitable for rotor speed variation. A performance and cost simulation model was set up for the Sikorsky UH-60A. Three different types of drivetrains were investigated: The Standard drivetrain, a 2 Speed gearbox and a continuously variable transmission (CVT). Flight missions of 3 industry sectors- Oil and Gas, Construction and Search and Rescue with a total of 33 different missions were simulated. The simulation was performed to evaluate the effects of the variable rotor speed technologies on performance and costs in the context of missions. It could be shown that rotor speed variation in a range of 50% can lead to less fuel consumption and mission costs in every industry sector and the performance of the helicopter can be increased. The CVT seems to be the better solution for multi purpose helicopters. In single missions the results can be different, therefore it is important to have a look on more different missions in an industry sector. The mass of the transmission system has an significant impact on the results. The results of the investigation can give an idea about the boundary conditions for the usage of rotor speed variation and show the critical points of rotor speed variation. The technology increases the efficiency, decreases fuel consumption and CO2emission and reduces noise and environmental impact of rotorcraft. Furthermore it can have also economic advantages for the operator.
Distributed Electric Propulsion and Flight Control Concept to Meet EASA SC-VTOL-01 10-9 Catastrophic Failure Criteria
Authors:   Boeing Co., Darmstadt Patrick ,   Anduril Industries Inc., Mistry Mihir , Arkebauer Andrew , Beiderman Allan , Chen Ephraim , Dillard Caitlin , Pathak Sheevangi
Published: April 2023

The objective of the current work was to develop an all-electric distributed propulsion and flight control (DPFC) architecture that will have no more than 10-9 catastrophic failures per flight hour (pfh). The DPFC architecture was broken into four system design teams, the (i) electrical power and distribution system, (ii) drive and power system, (iii) thermal management system (TMS), and (iv) flight control system (FCS). System designs were updated and iterated upon, working with reliability and safety analysis teams, to develop compliant designs. The firm designs were reflected in a preliminary system safety assessment (PSSA) for initial verification of compliance. Additionally, design and analysis excursions are presented in which aircraft attributes were modified to investigate sensitivities to propulsion type, number of rotors, and control schemes. Excursion results found that all aircraft evaluated likely have paths to comply with the stringent, probabilistic catastrophic failure criteria. However, S&C models showed large power transients that must be addressed and PSSA results show that future work is needed in single load path structures, high voltage power storage and distribution, and in motor/rotor overspeed protection.
Multi-Domain Electric Drivetrain Modeling for UAM-Scale eVTOL Aircraft
Authors:   Rensselaer Polytechnic Institute, Podlaski Meaghan , Gandhi Farhan , Niemiec Robert , Vanfretti Luigi
Published: April 2023

This paper presents the modeling and validation of an electric drivetrain through an object-oriented, equation-based framework that includes aerodynamics, electric machine, power electronic converter and battery models at various levels of detail. The proposed drivetrain model considers different losses in the machine and levels of fidelity for the power source and converters. It is simulated with various maneuvers, aiming to show the effects of modeling simplifications on the behavior of UAMs. These studies show that the level of detail in the motors and power system has significant impact on the dynamic response and power consumption of the system. This is most evident in the cases where the system uses a detailed battery model and in the cases where the switching electrical components are used, creating a torque ripple.
Exploring the knowledge, attitude, and practices of over-the-counter medical sellers in Ghana
Authors: Simister Sam , Flint Nicholas , Webb Joshua , Nyarko Obed , Secrest Aaron , Lewis Bethany , Dickerson Ty
Published: April 2023

Background: Rural areas in sub-Saharan Africa face a high prevalence and morbidity of skin disease while also lacking access to dermatologists. In Ghana, where approximately 25 licensed dermatologists are available for 25 million people, community pharmacies, called over-the-counter medical sellers (OTCMS), were established to respond to accessibility inequities, albeit without equitable training.Objective: Our study evaluates the dermatologic knowledge, attitudes, and practices (KAP) of OTCMS in Ghana’s Ashanti Region.Methods: To assess dermatologic KAP, we created a standardized questionnaire and recorded 13 interviews with OTCMS in seven communities. Interviews were completed with help from Ghanaian translators and transcripts were transcribed verbatim, then analyzed qualitatively to determine common themes for analysis. Results: This analysis identified six major themes: i) prescriber qualifications; ii) diagnostics; iii) therapeutics; iv) economics; v) health systems integration; vi) care-seeking behavior. Analysis of these themes outlined many cultural roles and challenges of OTCMS, including serving as the primary contact for dermatologic conditions in rural communities. While possibly necessary due to the lack of accessible dermatologists, this raises concerns for potential harm in diagnostic error and misuse of therapeutics due to the lack of formal dermatology training. Conclusion. In rural parts of Ghana, the KAP of OTCMS play a pivotal role in assessing and treating skin disease for those who might otherwise lack access to adequate dermatologic management. Furthermore, although our study identifies potential issues related to the roles played by OTCMS, it also suggests strategies to improve the dermatologic health of many Ghanaians by enhancing education and healthcare delivery in rural areas.
Impact of COVID-19 on the antenatal care services utilization in the region of Guelmim Oued Noun, Morocco
Authors: Tikouk Jamal , Ait Boubkr Asmaa , Alami Chentoufi Mohammed
Published: April 2023

Background: The COVID-19 pandemic has seriously impacted access to healthcare facilities across the world, but there is little evidence of how the pandemic influences the use of essential healthcare in the world. Objective: This study aimed to evaluate the impact of the COVID-19 pandemic on antenatal indicators in the region of Guelmim Oued Noun, Morocco.Methods: The aggregated data was delivered by regional health authorities covering the period from January 2017 to December 2020. The interrupted time series was mobilized to conduct statistical analysis. Results: The descriptive results revealed a steady decline after the COVID-19 pandemic in antenatal indicators. The results of the regression model showed a negative impact of the pandemic on the antenatal recruitment rate (β2=-16.14; P0.01), recruitment rate of women in antenatal visits during the 1st quarter of pregnancy (β2=- 2.09; P0.01), antenatal visit completion rate (β2=-18.10; P0.05), and average number of visits/pregnancies (β2=-15.65, P0,05).Conclusion: The effect of the COVID-19 pandemic on antenatal rates was significant for almost all the indicators studied. Future studies should focus on the impact of the pandemic on postnatal and immunization services on a national scale.
Understanding the factors of road crash severity in Benin: a matched case-control study
Authors: Daddah Donatien , Ahanhanzo Yolaine Glèlè , Kpozehouen Alphonse , Dos-Santos Bella Hounkpe , Bonnet Emmanuel , Levêque Alain , Coppieters Yves
Published: April 2023

Background. In Benin, due to the unavailability of comprehensive data on road crashes, road safety policies are mainly based on partial statistics provided by the police. These remain unreliable in terms of injury severity and risk factors. This study aims to determine the factors influencing the severity of injuries after a road crash in Benin.Methods. The present nested case-control study, matched for age and sex, was based on a hospital cohort of road crash victims set up in five hospitals in Benin between July 2019 and January 2020. A sample of severely injured patients according to the Abbreviated Injury Scale (cases) was compared to non-severely injured patients (controls).Results. The severe crash occurred mainly during the night between 8 p.m. and midnight (36.2% of cases vs. 24.4% of controls) and on main roads (57.8% of cases vs. 34.7% of controls). Factors associated with injury severity were the time of the crash: night between 8 p.m. and midnight [Adjusted Odd Ratio (AOR): 2.1; CI 95%: 1.4-3.2], major roads (national interstate roads and national roads) (AOR: 2.8; CI 95%: 2.0-4.0) and non-work-related travel (AOR: 1.8; CI 95%: 1.2-2.7).Conclusions. Factors associated with road crash severity in Benin were night-time, main roads, and non-work related travel. Raising user awareness about compliance with traffic rules and improving public lighting, especially along main roads could help reduce the number of serious injuries.
Impact of neurological problems on mechanical ventilation and ICU outcomes in the pulmonary ICU patients
Authors: Çınar Zeynep , Aydın Eda Macit , Naurzvai Nurgul , Mammadova Ayshan , Kodalak Sümeyye , Abbasova Aygül , Gürsel Gül
Published: April 2023

Neurological problems (NP) are frequently connected with different critical illnesses in intensive care unit (ICU) patients, and they may have an influence on ICU outcomes. The aim of this study is to examine the effects of NPs on ICU outcomes, especially in pulmonary ICU patients. his is a retrospective observational study comprising adult pulmonary critical care patients who were hospitalized between 2015 and 2019. Frequency of NPs at admission, their impact on mechanical ventilation (MV), ICU out comes, the rate of NP development during ICU stay, and risk factors for them were investigated. A total of 361 patients were included in the study, and 130 of them (36%) had NPs (Group 1). NIV requirement rate in patients with NPs was less than in those without NPs (group 2) and the requirement of MV was significantly more frequent in this group (37% & 19%, p<0.05). The duration of MV and sepsis rate were also  higher in Group 1 (19±27& 8±6 days, p: 0.003, p<0.05). NPs developing after ICU admission increased MV requirement 3 times as an independent risk factor. Risk factors for ICU acquired NPs were the existence of sepsis during admission (OR: 2.01, CI95%:1.02-4, p: 0.045) and longer MV durations before ICU admission (OR: 1.05, CI95%:1.004-41.103, p: 0.033). NPs were not independent risk factors for mortality (OR: 0.67, CI 95%: 0.37-1.240, p: 0.207). NPs did not increase mortality but more frequently caused MV requirement, more extubation failure, and longer ICU stay in this study population. Additionally, our data suggest that having sepsis during admission and a longer length of MV prior to admission may increase the neurological complication rate.
Hemodialysis Access Surveillance
Authors: Ibrahim Atif , Ali Hatem , Raza Hafiz , Mohamed Mahmoud
Published: April 2023

Vascular access (VA) care is considered the “Achilles heel” for the success of hemodialysis operation. Early detection of VA stenosis remains a major challenge for clinical nephrologists. Various studies tried to create methods with robust accuracy for assessing VA blood flow. It is estimated that roughly 80% of VAs fail due to thrombosis. Failure to provide patients with one is a common factor leading to significant morbidity and mortality among hemodialysis (HD) patients with an estimated annual cost around 1 billion US dollars. In the following, we have attempted to review all the available trials and meta-analysis done to date to assess the true effect of VA blood flow monitoring for the purpose of early detection of thrombosis and over-minimizing the rate of intervention. A thorough and systematic search for the available literature was done on several databases such as MEDLINE, EMBASE, Cochrane library and reviewed clinical trials.gov to look for studies involving dialysis access blood flow measurement. We also reviewed the available randomized control trials and meta-analysis done on this subject so far, and the results have a variable outcome. We concluded that arteriovenous access blood flow surveillance using non-invasive ultrasound dilution and Doppler ultrasound methods in detecting stenosis may have a vital and crucial role in lowering the risk of thrombosis, promoting early management and increasing access survival.
“Family Intervention” – A Key to Unlock the Psychiatric Morbidities in Transsexuals
Authors: Sanjay Lakshmi , Selvaraj Arun , Dass Vinoth Krishna , Perarul S
Published: April 2023

Transsexuals, who form a part in LGBT community, face a great amount of distress due to social stigma and lack of family support. This case series emphasizes the effect of family stigma in three such transsexuals, who presented with psychiatric complaints. A definitive need for scientific research and its application exists to address this stigma and discrimination. ICD-10 criteria were used to diagnose the psychiatric morbidities. Standard scores (Hamilton Depression Rating Scale and Suicidal Affect Behavior Cognition Scale) were used to assess the severity. Familial, individual, and interpersonal level interventions were administered. Significant improvements were seen in two patients (received family therapy) and one patient who did not receive therapy continued to be distressed. Psychological interventions resulted in reducing the family stigma and psychiatric morbidities suffered by them. This is an effort to show the need for implementation of such standard protocols in health-care facilities to address the stigma faced by transsexuals.