bluuebunny/crossref_metadata_2025_split huggingface dataset:
Caracterización de señales de precipitación mediante la transformada de Fourier y transformada Wavelet
Authors:   , Moros Vivas Ana María 
Published: July 2022

Esta investigación busca ofrecer a ingenieros e investigares de las ciencias de la tierra, herramientas conceptuales y computacionales que faciliten la interpretación de señales bajo los lentes de una transformada. Por consiguiente, se ha desarrollado un documento útil y practica que facilite el análisis de señales por medio de la Transformada Wavelet, partiendo desde la Transformada de Fourier y pasando por la Transformada de Fourier de Tiempo Corto. El documento está estructurado con 11 capítulos que se distribuyen de la siguiente manera: el capitulo 1, 2 y 3 corresponde a la introducción, objetivos y antecedentes. El capitulo 4 contiene la caracterización de la serie de tiempo desde el punto de vista estadístico. El capítulo 5 se centra en el análisis de Fourier permitiendo ver la señal en términos de "Potencia vs Frecuencia". Seguidamente, se introduce al lector a la aplicación de los procedimientos del análisis de Fourier a intervalos cortos de tiempo, con el fin de poder localizar en el tiempo las frecuencias de una señal (6). Luego se extienden características del Análisis de Fourier de Tiempo Corto al utilizar ventanas de tamaño variable que permiten analizar series no estacionarias a diversas escalas, ofreciendo un panorama más amplio y profundo en el campo del procesamiento y análisis de señales (7). El capitulo 8 contiene la principales conclusiones la cual se llegaron al final del desarrollo del presente documento y además se sugieren algunas recomendaciones a seguir en futuras investigaciones a partir del presente estudio. Los capítulos 9, 10 y 11 contienen bibliografía, anexos de : funciones ortogonales y rutinas programadas soportadas por Matlab, y los apéndices se presenta información relaciona son Señales Básicas y Convolución.
Effects of Body Geometry and Propulsion Type on Unmanned Underwater Vehicle Interactions With Marine Vegetation
Authors: Vanessa Anuat G. , Klamo Joseph T. , Pollman Anthony G. 
Published: July 2022

Abstract
Interactions with marine vegetation can disrupt unmanned underwater vehicle missions. Very little information is publicly available about the mechanisms causing these interactions or the consequences of them. This article compares the interactions between three different style underwater vehicles and two different types of marine vegetation. Similar test setups and procedures were used to allow for the direct comparison between REMUS-100, BlueROV2, and GhostSwimmer vehicles. Experimental test runs were conducted at different vegetation densities using either synthetic eelgrass or synthetic giant kelp. The resulting interactions depended on the vegetation type, vegetation density, propulsion mechanism of the vehicle, and vehicle geometry. Synthetic giant kelp caused a multitude of interactions with the dominant ones being interference, blockage, and entanglement with the vehicle body. Collectively, these three interactions occurred 84% of the time on giant kelp runs where an interaction was observed. Eelgrass caused propeller entanglement and even body blockage depending on the unmanned underwater vehicle geometry. In high density eelgrass, we observed that a spinning propulsion mechanism experiences entanglement 100% of the time when at low speed. The use of an oscillating tail for propulsion coupled with a completely streamlined body appears to successfully mitigate adverse marine vegetation interactions.
Compression of Particulate Materials in Wellbore Fractures and Enhancement in the Wellbore Breakdown Limit
Authors: Nguyen Kien , Mehrabian Amin , Bathija Arpita P. , Santra Ashok 
Published: July 2022

Abstract
Fluid loss during subterranean drilling often occurs through fractures that develop or preexist around the wellbore. Particulate additives, known as lost circulation material (LCM), are commonly added to the drilling fluid to mitigate lost circulation. The LCM forms an impermeable agglomerate within the fractures while preventing further tensile failure of the wellbore wall. The outcome is enhancement in the wellbore breakdown limit. A semi-analytical elastic solution is developed to estimate the width of near-wellbore fractures that partially close on the LCM agglomerate. The solution uses stress–strain data from confined compression testing on LCMs. The compression test results are modeled through a modified form of Kawakita’s (1971) powder compaction equation. The developed constitutive model is embedded within the described semi-analytical solution for the wellbore fractures. The solution adopts an incremental loading approach to treat the nonlinearities arising from the characterized LCM constitutive behavior, as well as large deformation of the LCM agglomerate within the partially closed fractures. At each incremental load, the nonlocal stress equilibrium along the fracture length is described via an integral equation. Successive solutions to these integral equations determine the unknown fracture width of partially closed fractures. A competition between the fractures tendency for propagation and the wellbore wall tendency for secondary tensile failure determines the overall stability of the fractured wellbore. Mechanical behavior of the LCM agglomerate under compression is identified as a key parameter that controls both mechanisms, thereby, the gain in breakdown limit of a fractured and LCM-treated wellbore.
Towards Integrated Design and Operation of Complex Engineering Systems With Predictive Modeling: State-of-the-Art and Challenges
Authors: Liu Xinyang , Ghosh Sayan , Liu Yongming , Wang Pingfeng 
Published: July 2022

Abstract
Growing trends towards increased complexity and prolonged useful lives of engineering systems present challenges for system designers in accounting for the impacts of post-design activities (e.g., manufacturing, condition monitoring, remaining life prediction, maintenance, service logistics, end-of-life options, etc.) on system performance (e.g., costs, reliability, customer satisfaction, environmental impacts, etc.). It is very difficult to develop accredited lifecycle system performance models because these activities only occur after the system is built and operated. Thus, system design and post-design decision-making have traditionally been addressed separately, leading to suboptimal performance over the systems lifecycle. With significant advances in computational modeling, simulation, sensing & condition monitoring, and machine learning & artificial intelligence, the capability of predictive modeling has grown prominently over the past decade, leading to demonstrated benefits such as improved system availability and reduced operation and maintenance costs. Predictive modeling can bridge system design and post-design stages and provide an optimal pathway for system designers to effectively account for future system operations at the design stage. In order to achieve optimal performance over the system’s lifecycle, post-design decisions and system operating performance can be incorporated into the initial design with the aid of state-of-the-art predictive modeling approaches. Therefore, optimized design and operation decisions can be explored jointly in an enlarged system design space. This article conducted a literature review for the integrated design and operation of engineering systems with predictive modeling, where not only the predictive modeling approaches but also the strategies of integrating predictive models into the system design processes are categorized. Although predictive modeling has been handled from data-driven, statistical, analytical, and empirical aspects, and recent design problems have started to evaluate the lifecycle performance, there are still challenges in the field that require active investigation and exploration. So, in the end, this article provides a summary of the future directions that encourages research collaborations among the various communities interested in the optimal system lifecycle design.
Shear Fracture Criterion of Advanced High-Strength Steel Based on Stress Triaxiality and Equivalent Strain
Authors: Fu Q. T. , Li D. , Song H. , Liu X. F. , Xu J. C. , Jiang N. 
Published: July 2022

Abstract
Advanced high-strength steel (AHSS) is increasingly used in the automotive industry due to its higher strength and lower weight. The traditional forming limit criterion cannot accurately predict the unique shear fracture of AHSS, so great efforts have been made to develop failure criteria that can predict shear fracture. In this paper, a series of tensile and shear tests for four steel sheets of AHSS are designed, the stress triaxiality and equivalent strain to fracture are solved, and the correlation between them and the performance parameters of steel sheets K and n is studied. In order to study the relationship between stress triaxiality and equivalent strain to fracture in the range of low-stress triaxiality, the Hill'48 orthotropic model and modified Mohr–Coulomb (MMC) fracture model were used to establish tensile and shear fracture models of four dual-phase sheets of steel, simulating and studying the plastic fracture of AHSS. Solving the relevant parameters enriches the stress triaxiality of the four steel types, establishes the relationship between the stress triaxiality and the equivalent strain to fracture, and verifies its correctness through tensile and bending tests and simulations. The results show MMC can accurately predict the fracture of these four dual-phase steels, and the quantitative relationship between stress triaxiality and equivalent strain to fracture of the four dual-phase steels in the low-stress triaxiality range 0–0.3 is similar, which can be established and expressed by the performance parameters of each steel type.
Impact of Solar Intensity on Photovoltaic-Generated Current Harmonics and Transformer Life: A Mathematical Model With Experimental Validation
Authors: Rajput Saurabh Kumar , Dheer Dharmendra Kumar 
Published: July 2022

Abstract
With the rising penetration of photovoltaic (PV) plants on low voltage distribution systems, the generation of current harmonics as well as its impact on transformer operation is a current concern. The present research work develops a mathematical relationship of solar intensity (I(t)) with PV-inverter-generated total harmonic distortion of current (THDi,inv.), and then uses IEEE recommendations to present the impact of THDi,inv. on the life of a three-phase distribution transformer (TPDT). The validation of the presented model is done by real-time data monitoring from a 100-kWp solar roof-top photovoltaic (SRTPV) system, integrated with an 11-kV grid supply through a 63-kVA TPDT in the composite environment of north India. According to the results, decreasing I(t) values from 857 W/m2 to 35 W/m2 raise THDi,inv. from 3.57% to 63.43%. It is also observed that the production of poor THDi,inv. is high in the winter season (daily average = 27.44%) in comparison to their values in the summer season (daily average = 15.21%). For I(t) values less than 315 W/m2, the generation of large THDi,inv. (above 15%) takes place and it increases the loss of life of TPDT by a factor of 6.0.
Numerical Simulations of a Lifted Hydrogen Jet Flame Using Flamelet Generated Manifold Approach
Authors: Xia Yu , Verma Ishan , Nakod Pravin , Yadav Rakesh , Orsino Stefano , Li Shaoping 
Published: July 2022

Abstract
A turbulent lifted H2/N2 jet flame in a vitiating coflow environment is numerically investigated, using the Flamelet generated manifold (FGM) combustion model with large eddy simulations (LES). Due to the hot vitiated H2/air coflow, the primary stabilization mechanism is the auto-ignition followed by a premixed flame. In addition to using H2 as a fuel, this flame poses two other modeling challenges: (i) the auto-ignition, which is a transient chemistry-driven phenomenon; (ii) the existence of multiple combustion regimes, e.g., diffusion at auto-ignition location but premixed in the postflame. A series of LES/FGM simulations are completed in this work by reducing the coflow temperature from 1045 K to 1000 K. The FGM model can predict the characteristics of the flame by showing a lifted flame. It also accurately predicts the trend in the flame lift-off distance with a change in the coflow temperature. The current results are compared for mixture fraction, temperature, and OH mass fraction at multiple locations, which have also been correctly captured. It is noted that for a high coflow temperature (and hence a low lift-off distance), the flame's lift-off is highly sensitive to the inlet boundary conditions and the mesh resolution near the jet entry. A relatively coarse mesh is used for all the simulations, which is generated using a careful strategy that not only resolves the jet instabilities near the fuel inlet but also keeps the overall mesh count low and allows for a large computational time step. A systematic sensitivity analysis of the computational speed is also performed. This work provides some useful guidelines for simulating the H2 diluted flames using the FGM model, which may be valuable to the gas turbine industry.
Don’t Throw the Baby Out With the Bathwater: Talent in Swimming Sprinting Events Might Be Hidden at Early Age
Authors: Brustio Paolo Riccardo , Cardinale Marco , Lupo Corrado , Boccia Gennaro 
Published: July 2022

Purpose: This study aimed to describe the career performance progression of elite early- and later-success international swimmers competing in sprint events (ie, 50 and 100 m). Methods: The career performance trajectories of 6003 swimmers (50.9% females; 58,760 unique records) competing in the 4 swimming strokes were evaluated. Swimmers with early and later success were identified. The authors identified the top 50 all-time swimmers competing in junior career who did not reach the top 50 rankings in their senior career, and vice versa, and successful swimmers in both junior and senior career. Results: Early-success swimmers mainly achieved their peak performance before the age of 20 years and approximately 5–6 years before successful senior swimmers or approximately 3–4 years before successful swimmers both in junior and senior careers. The annual performance improvements of later-success swimmers were higher (about 1%–2%) until the age of 20 to 24 years, whereas early-success swimmers showed a performance stagnation at about 16 to 18 years in females and 19 to 20 years in males. Conclusions: Early-success swimmers who achieved peak performance at a young age were unable to maintain the same level of competitiveness in adulthood as they experienced a plateau in performance from the age of 20 years. The procedure of considering early performances solely for talent identification (and not the current rate of progression) might represent a limited approach for selecting future elite swimmers. Our results indicate that performance progression in the transition toward adult careers might be a strong indicator of performance potential.
Supplemental Material: New Insights into Feeder Dike Swarms in Scoria Cones and Their Structural Control: A Case Study in the Michoacán-Guanajuato Volcanic Field
Authors: Gómez-Vasconcelos M.G. , al. et 
Published: July 2022

<p> Figures S1 and S2: Field pictures. Figure S3: Ar/Ar plateau age plots. Table S1: Characterization of the dike swarm. </p>
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Turning users into ‘unofficial brand ambassadors’: marketing of unhealthy food and non-alcoholic beverages on TikTok
Authors: Brooks Ruby , Christidis Rebecca , Carah Nicholas , Kelly Bridget , Martino Florentine , Backholer Kathryn 
Published: July 2022

IntroductionTikTok has over one billion monthly users and is particularly popular among children. We examined the (1) use of owned media by major unhealthy food and non-alcoholic beverage brands on TikTok and (2) nature of branded hashtag challenges instigated by such brands and the user-generated content created in response.MethodsWe assessed the (1) content of all videos posted on the accounts of 16 top food and non-alcoholic beverage brands (based on global brand share) as at 30 June 2021, and (2) content and sentiment of a sample of brand-relevant user-generated content created in response to branded hashtag challenges instigated by these brands.ResultsOf 539 videos posted by brands, 60% were posted in the first half of 2021. The most common marketing strategies were branding (87% of videos), product images (85%), engagement (31%) and celebrities/influencers (25%). Engagement included instigation of branded hashtag challenges that encouraged creation of user-generated content featuring brands’ products, brands’ videos and/or branded effects. The total collective views of user-generated content from single challenges ranged from 12.7 million to 107.9 billion. Of a sample of 626 brand-relevant videos generated in response to these challenges, 96% featured branding, 68% product images and 41% branded effects. Most portrayed a positive (73%) or neutral/unclear (25%) sentiment, with few negative (3%).ConclusionUnhealthy food and non-alcoholic beverage brands are using TikTok to market brands and products via their own accounts and to encourage users to create and share their own content that features branding and product images. Given TikTok’s popularity among children, this study supports the need for policies that protect children from the harmful impact of food marketing on social networking platforms.
Experiences of general practitioners explaining central sensitisation to patients with persistent physical symptoms: a focus group study
Authors: den Boer Carine , Terluin Berend , van der Wouden Johannes C , Blankenstein Annette H , van der Horst Henriëtte E 
Published: July 2022

ObjectivePatients with persistent physical symptoms (PPS) require an explanation that is acceptable and comprehensible to them. Central sensitisation (CS) is an explanatory model for PPS and chronic pain that has been broadly applied in the context of pain medicine, but, until recently, not by general practitioners (GPs). We explored how GPs used the CS model in their consultations with patients with PPS.Design and settingA qualitative focus group study among GPs in the Netherlands.MethodsWe instructed 33 GPs on how to explain CS to patients with PPS. After 0.5–1.5 years of using the CS model, 26 GPs participated in focus groups and interviews to report and discuss their experiences with CS as an explanatory model. Audio recordings were transcribed and two researchers independently analysed the data. The text was coded, codes were organised into themes and discussed until consensus was reached.ResultsWe identified eleven themes and grouped these into four categories.The GPs regarded the CS model as evidence-based, credible and giving recognition to the patient. On the other hand, they found explaining the CS model difficult and time-consuming. They tailored the CS model to their patients’ needs and used multiple consultations to explain the model. The GPs reported that the use of the CS model seemed to improve the understanding and acceptance of the symptoms by the patients and seemed to reduce their need for more diagnostic tests. Furthermore, patients seemed to become more motivated to accept appropriate therapy.ConclusionGPs reported that they were able to provide explanations with the CS model to their patients with PPS. They regarded the model as evidence-based, credible and giving recognition to the patient, but explaining it difficult and time-consuming.
Safety, feasibility and initial efficacy of an app-facilitated telerehabilitation (AFTER) programme for COVID-19 survivors: a pilot randomised study
Authors: Capin Jacob John , Jolley Sarah E , Morrow Mary , Connors Meghan , Hare Kristine , MaWhinney Samantha , Nordon-Craft Amy , Rauzi Michelle , Flynn Sheryl , Stevens-Lapsley Jennifer E , Erlandson Kristine M 
Published: July 2022

ObjectivesDetermine the safety, feasibility and initial efficacy of a multicomponent telerehabilitation programme for COVID-19 survivors.DesignPilot randomised feasibility study.SettingIn-home telerehabilitation.Participants44 participants (21 female, mean age 52 years) discharged home following hospitalisation with COVID-19 (with and without intensive care unit (ICU) stay).InterventionsParticipants were block randomised 2:1 to receive 12 individual biobehaviourally informed, app-facilitated, multicomponent telerehabilitation sessions with a licenced physical therapist (n=29) or to a control group (n=15) consisting of education on exercise and COVID-19 recovery trajectory, physical activity and vitals monitoring, and weekly check-ins with study staff. Interventions were 100% remote and occurred over 12 weeks.Primary and secondary outcome measuresThe primary outcome was feasibility, including safety and session adherence. Secondary outcomes included preliminary efficacy outcomes including tests of function and balance; patient-reported outcome measures; a cognitive assessment; and average daily step count. The 30 s chair stand test was the main secondary (efficacy) outcome.ResultsNo adverse events (AEs) occurred during testing or in telerehabilitation sessions; 38% (11/29) of the intervention group compared with 60% (9/15) of the control group experienced an AE (p=0.21), most of which were minor, over the course of the 12-week study. 27 of 29 participants (93%; 95% CI 77% to 99%) receiving the intervention attended ≥75% of sessions. Both groups demonstrated clinically meaningful improvement in secondary outcomes with no statistically significant differences between groups.ConclusionFully remote telerehabilitation was safe, feasible, had high adherence for COVID-19 recovery, and may apply to other medically complex patients including those with barriers to access care. This pilot study was designed to evaluate feasibility; further efficacy evaluation is needed.Trial registration numberNCT04663945.