bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Integration of Structural and Fluid Film Dynamic Elements in Foil Bearings: Part I — Past Approaches to the Problem
Authors: Heshmat Hooshang 
Published: February 2021

Abstract
A review was conducted on work done in the past on the performance of foil bearings. The main aim of the survey was to see how the two-tiered construction of foil bearings, consisting as they do of two generically disparate elements, one hydrodynamic in nature and the other following the laws of elasticity, have been modeled in order to obtain integrated values of bearing stiffness and damping. A compilation was made of the parameters and processes inherent in the operation of foil bearings, including the kinematics of the bump foil and the accompanying Coulomb friction and damping. The main effort went into examining the results obtained from different dynamic models aimed at obtaining the values of the stiffness and damping coefficients. In Part II of this investigation it is shown that serious discrepancies exist between theory and experimental results and a new approach is offered for modeling the two-tiered domain of foil bearings to calculate the dynamic coefficients.
On the Vibration of Rotor With Rotor/Stopper Rubbing
Authors: Dai Xingjian , Zhang Xiaozhang , Jin Zhaoxiong 
Published: February 2021

Abstract
The vibration of a flywheel rotor with rotor/stopper rubbing is investigated by experimental methods. In the experiments, the large amplitude of the rotor vibration is excited by the electromagnetic harmonic excitation force and thus causes the rubbing between the rotor and the stopper. The stable rubbing rotor vibration shows that the stopper can limit the amplitude of low frequency precession effectively. The rotor to stopper collision and rub appears occasionally. The rubbing has little effect on the rotating speed of the rotor. The forced vibration becomes complex and nonlinear in the time and frequency domain when the collision and rubbing occurs. The observed high order harmonics are sub-synchronous but not subharmonic response. The second modal forward whirl of the rotor-bearing system is excited by the impact force and decays quickly.
Reduction of the 2F-Vibrations of Simple Flexible Rolls by Partial Machining
Authors: Wiese D. , Breitwieser M. 
Published: February 2021

Abstract
In paper and foil production plant, roll vibrations occurring at twice the rotational frequency often present serious problems. These are caused by anisotropy of roll stiffness — referred to below as stiffness anisotropy.
In the past the reduction of this stiffness anisotropy was impossible. When vibrations occurring at twice the frequency of rotation became too high, the entire roll had to be scrapped.
This paper deals with a method for the identification of the anisotropy of rotor stiffness on a balancing machine.
If the stiffness anisotropy is known, vibrations occurring at twice the frequency of rotation can be systematically reduced to a tolerable level by partial machining of the roll.
Application of the Mode-Acceleration Technique to the Solution of the Moving Oscillator Problem
Authors: Pesterev Alexander V. , Bergman Lawrence A. 
Published: February 2021

Abstract
The problem of calculating the dynamic response of a one-dimensional distributed parameter system excited by an oscillator traversing the system with an arbitrarily varying speed is investigated. An improved series representation for the solution is derived that takes into account the jump in the shear force at the point of the attachment of the oscillator, which makes it possible to efficiently calculate the distributed shear force and, where applicable, bending moment. The improvement is achieved through the introduction of the “quasi-static” solution, an approximation to the desired one, which makes it possible to apply to the moving oscillator problem the “mode-acceleration” technique conventionally used for acceleration of series in problems related to the steady-state vibration of distributed systems. Numerical results illustrating the efficiency of the method are presented.
Aerodynamic Flow Control Using Shape Adaptive Surfaces
Authors: Pern N. J. , Jacob J. D. 
Published: February 2021

Abstract
The present paper discusses results of experiments on flow control using an adaptive circular arc airfoil. A modified THUNDER actuator (piezoceramic bonded with a metallic substrate) serves as an adaptive airfoil that allows leading edge displacements of approximately 1 cm. The airfoil’s radius of curvature Rc is varied by altering the voltage applied across the upper and lower surfaces. The maximum input voltage varies Rc ±2% resulting in a variation in the lift coefficient Cl of approximately 7% at a frequency up to 25 Hz. Results of wake mitigation and flutter control tests are briefly discussed.
Use of Higher Order Spectra in Condition Monitoring: Simulation and Experiments
Authors: Rivola Alessandro , White Paul R. 
Published: February 2021

Abstract
In the field of machine condition monitoring one can observe that a link exists between machine vibrations and its health condition, that is, there is a change in the machine vibration signature when machine faults occur. Damages occurring in machine elements are often related to non-linear effects, which may lead to non-linearities in the machine vibration. This paper concerns the study of some systems by means of techniques based on Higher Order Spectra (HOS). These techniques are particularly useful in the situation where only a single measurement sensor is available. If a process is Gaussian then HOS provide no information that cannot be obtained from the second order statistics. On the contrary, HOS give information about a signal’s non-Gaussianity. Since a Gaussian input passing through a linear system leads to a Gaussian output, assuming the signal as an output of a system with a Gaussian input, then HOS make it possible to analyse the structure of the output signal and to provide information related to the non-linearity within the system. A simple model is presented with the aim of showing the effectiveness of the normalised version of polyspectra in detecting different kinds of system non-linearities. HOS are used to interpret the signal structure and the system’s physical characteristics. Moreover, two experimental cases are presented. The HOS are applied to detect the presence of a fatigue crack in a straight beam and to analyse the vibration signal measured on a test bench for rolling element bearings. Both third and fourth order spectra seem to provide a possibility of using HOS as a condition monitoring tool.
On the Planar Damped Linear Vibrations of a Rigid Body
Authors: Blanchet Pat , Lipkin Harvey 
Published: February 2021

Abstract
The planar motion associated with a damped mode of a vibrating rigid body is actually not well understood. This paper shows that a damped mode is a rotation about a point that is either translating along a straight line or is stationary, depending on how much damping is present. The transition between each type of damping is explained and an example illustrates the results.
Analysis of Motion of the Impact-Dry-Friction Pair of Bodies and its Application to the Investigation of the Impact Dampers Dynamics
Authors: Peterka František 
Published: February 2021

Abstract
The motion with impacts and dry friction forces appears in some mechanical systems as mechanisms with clearances, (e.g., in gearings, pins, slots, guides, valve gears etc.), impact dampers, relays, forming and mailing machines, power pics etc. Such mechanisms include one or more pairs of impacting bodies, which introduce the strong nonlinearity into the system motion. The motion of the general pair of bodies with the both-sides impacts and dry friction forces is assumed (Fig.1). It can be the part of a more complex chain of masses in the mechanical system. Dead zones in the relative motion of bodies can be caused by assumed nonlinearities. The mathematical conditions controlling the numerical simulations or analytical solution of the motion are introduced. The application of this method is explained by the study of the influence of dry friction force on amplitude-frequency characteristics of four types of dynamical and impact dampers with optimised parameters.
Modelling and Analysis of Dynamic Properties of Drive Systems With Gears
Authors: Kratochvíl Ctirad , Kotek Vladimír , Březina Tomáš , Krejsa Jiří 
Published: February 2021

Abstract
Contemporary trends show a marked tendency for solution of problems of dynamic analysis of drive systems as early as the design stage. It shows that during the modelling of complex drive systems it is necessary to respect its structural complexity and therefore it is necessary to make the models of particular drive subsystems first and then to combine it altogether. In the paper authors present some methods of creation of suitable mathematical models of complex drive systems respecting the drive structure. The methods are then applied onto real tasks. Examples are included.
Instant Chaos and Extreme Parametric Uncertainty in Nonlinearly Driven Continuum Mechanics
Authors: Schwartz Ira B. , Wood Yvette K. , Georgiou Ioannis T. 
Published: February 2021

Abstract
Bifurcation to high-dimensional hyperchaos is observed in a driven coupled pendulum-flexible rod system. When the rod is in resonance with the pendulum, the system changes from a low dimensional periodic attractor to a high dimensional chaotic attractor abruptly. It is shown that high dimensional chaotic dynamics is hysteretic, and exhibits extreme sensitivity with respect to small parameter changes. Such sensitivity poses a problem in obstructing predictability in mechanics.
The Influence of Biological Maturity on Sprint Speed, Standing Long Jump, and Vaulting Performance in Young Female Gymnasts
Authors: Moeskops Sylvia , Oliver Jon L. , Read Paul J. , Myer Gregory D. , Lloyd Rhodri S. 
Published: February 2021

Purpose: To quantify speed, peak momentum, standing long jump (SLJ), and the ratio of vertical to horizontal take-off velocity (Ratiovert–hori TOV) in young female gymnasts of different maturity status and their influence on vaulting vertical TOV. Methods: One hundred twenty gymnasts age 5–14 years were subdivided into maturity groupings using percentage of predicted adult height. Participants performed three 20-m sprints, SLJ, and straight jump vaults that were recorded using 2-dimensional video and analyzed using digitizing software. Results: All speed intervals, peak speed, peak momentum, SLJ distance, vault height, and vertical TOV increased between the early prepubertal and late prepubertal (P < .001; d = 0.65–1.10) and early prepubertal and pubertal (P < .001; d = 0.75–1.00) groups. No differences between these metrics were observed between the 2 most mature groups (d = 0.01–0.55). Multiple regression analyses revealed peak speed had the strongest association with vertical TOV (R2 = 59%) and also identified the Ratiovert–hori as a secondary determinant (R2 = 12%). A separate regression model indicated that maturity status (percentage of predicted adult height) moderately influences vertical TOV during vaulting (R2 = 41%). Conclusion: Speed and SLJ performance increase between the early prepubertal and late prepubertal years in young female gymnasts. However, given that peak speed and Ratiovert–hori combined to explain 71% of the total variance in vaulting vertical TOV, in order to increase aerial time for more advanced vaulting, practitioners should attempt to enhance peak speed alongside takeoff technique to develop gymnasts’ ability to transfer linear speed to vertical TOV.
Demands of the Tour de France: A Case Study of a World-Class Sprinter (Part I)
Authors: van Erp Teun , Kittel Marcel , Lamberts Robert P. 
Published: February 2021

Purpose: To describe the intensity, load, and performance characteristics of a world-class sprinter competing in the Tour de France (TdF). Method: Power output (PO) data were collected from 4 editions of the TdF (2013, 2014, 2016, and 2017) and analyzed. Load, intensity distribution in 5 PO zones, and the maximal mean PO for multiple durations were quantified. Stages were divided in accordance with the 4 different editions of the TdF, as well as the 4 different stage types, that is, flat (FLAT), semimountainous (SMT), mountain (MT), and (team) time trials. In addition, based on their location within the stage, mountain passes were further classified as BEGINNING, MIDDLE, or END of the stage. Results: No differences in load, intensity, and performance characteristics were found when the 4 editions of the TdF were compared. Time trials were associated with higher intensities but a lower load compared to the other stage types. MT showed higher load and intensity values compared to FLAT and SMT stages. FLAT stages were higher in short maximal mean PO (≤1 min), whereas MT stages showed higher longer endurance maximal mean PO values (≥20 min). In addition, mountain passes situated at the BEGINNING of the stage were completed with a higher PO, cadence, and speed compared with mountain passes situated at the END. Conclusions: A world-class sprinter sustains a higher load and spends more time in the high-intensity zones when competing in the TdF than previously reported values suggested. To finish the MT stages as efficiently as possible, sprinters adopt a reverse pacing strategy.
“He Leaned His Body Against Mine and Pushed Himself Against Me”: A Narrative of Sexual Harassment in Mental Performance Consulting
Authors: DeLisio Danielle C. , Lauer E. Earlynn , Shigeno Terilyn C. , Fisher Leslee A. , Zakrajsek Rebecca A. 
Published: February 2021

Mental performance consultants in training need to be prepared to respond to the various ethical dilemmas they may encounter, including sexual misconduct. Sexual harassment (i.e., unwanted attention of a sexual nature that may create an uncomfortable environment) is a form of sexual misconduct that has increased dramatically in the general U.S. population. In this paper, the authors provide a composite narrative from the point of view of the “victim” of sexual harassment (i.e., a neophyte mental performance consultant) while consulting with a high school team. Then, the authors examine and interpret the narrative in light of four complicating factors: (a) gender identity and other demographics, (b) context, (c) training and experience, and (d) handling/reporting incidents of sexual harassment. Finally, the authors pose questions for readers related to each complication and present implications for sport psychology students and faculty.
Practitioners’ Use of Motivational Interviewing in Sport: A Qualitative Enquiry
Authors: Mack Rory , Breckon Jeff , Butt Joanne , Maynard Ian 
Published: February 2021

This study explored the use of motivational interviewing (MI) in sport contexts by experts in that approach. Specifically, the purpose was to understand which aspects of the MI approach are deemed valuable for working in sport and to begin to understand how these aspects are best applied. Nine practitioners participated in semistructured interviews, and thematic analysis identified themes related to core and subcomponents of MI (e.g., relational spirit, technical microskills, applied tools, and the MI communication styles continuum). Additional themes relate to integrating MI with other interventions, the challenges of working with athletes (e.g., mandated attendance, ambivalence about change), and unique aspects of working in sport contexts (e.g., frequency, duration, and location of contact points). The participants also outlined essential ingredients for an MI training curriculum for practitioners in sport. This counseling approach appears to have valuable relational and technical components to facilitate the building of the therapeutic alliance, enhance athlete readiness for change, and support delivery of action-oriented interventions in applied sport psychology.
Further evidence for the Matanuska megaflood hypothesis, Alaska
Authors: Wiedmer R. Michael , Gillespie Alan R. , Montgomery David R. , Greenberg Harvey M. 
Published: February 2021

ABSTRACT
The Matanuska lowland north of Anchorage, Alaska, was episodically glaciated during the Pleistocene by the merged westward flow of the Matanuska and Knik glaciers. During the late Wisconsin glaciation, glacial Lake Atna filled the Copper River Basin, impounded by an ice dam blocking the Matanuska drainage divide at Tahneta Pass and the adjacent Squaw Creek headwaters and ice dams at other basin outlets, including the Susitna and Copper rivers. On the Matanuska lowland floor upvalley from the coalesced glacier’s late-Wisconsin terminus, a series of regularly spaced, symmetrical ridges with 0.9-km wavelengths and heights to 36 m are oriented normal to oblique to the valley and covered by smaller subparallel ridges with wavelengths typically ~80 m and amplitudes to 3 m. These and nearby drumlins, eskers, and moraines were previously interpreted to be glacial in origin. Borrow-pit exposures in the large ridges, however, show sorting and stratification, locally with foreset bedding. A decade ago we reinterpreted such observations as evidence of outburst flooding during glacial retreat, driven by water flushing from Lake Atna through breaches in the Tahneta Pass and Squaw Creek ice dam. In this view, the ridges once labeled Rogen and De Geer moraines were reinterpreted as two scales of fluvial dunes. New observations in the field and from meter-scale light detection and ranging (LiDAR) and interferometric synthetic aperture radar (IfSAR) digital elevation models, together with grain-size analyses and ground-penetrating radar profiles, provide further evidence that portions of the glacial landscape of the Matanuska lowlands were modified by megaflooding after the Last Glacial Maximum, and support the conclusion that the Knik Glacier was the last active glacier in the lowland.
Associations of cereal grains intake with cardiovascular disease and mortality across 21 countries in Prospective Urban and Rural Epidemiology study: prospective cohort study
Authors: Swaminathan Sumathi , Dehghan Mahshid , Raj John Michael , Thomas Tinku , Rangarajan Sumathy , Jenkins David , Mony Prem , Mohan Viswanathan , Lear Scott A , Avezum Alvaro , Lopez-Jaramillo Patricio , Rosengren Annika , Lanas Fernando , AlHabib Khalid F , Dans Antonio , Keskinler Mirac Vural , Puoane Thandi , Soman Biju , Wei Li , Zatonska Katarzyna , Diaz Rafael , Ismail Noorhassim , Chifamba Jephat , Kelishadi Roya , Yusufali Afzalhussein , Khatib Rasha , Xiaoyun Liu , Bo Hu , Iqbal Romaina , Yusuf Rita , Yeates Karen , Teo Koon , Yusuf Salim 
Published: February 2021

Abstract

Objective
To evaluate the association between intakes of refined grains, whole grains, and white rice with cardiovascular disease, total mortality, blood lipids, and blood pressure in the Prospective Urban and Rural Epidemiology (PURE) study.

Design
Prospective cohort study.

Setting
PURE study in 21 countries.

Participants
148 858 participants with median follow-up of 9.5 years.

Exposures
Country specific validated food frequency questionnaires were used to assess intakes of refined grains, whole grains, and white rice.

Main outcome measure
Composite of mortality or major cardiovascular events (defined as death from cardiovascular causes, non-fatal myocardial infarction, stroke, or heart failure). Hazard ratios were estimated for associations of grain intakes with mortality, major cardiovascular events, and their composite by using multivariable Cox frailty models with random intercepts to account for clustering by centre.

Results
Analyses were based on 137 130 participants after exclusion of those with baseline cardiovascular disease. During follow-up, 9.2% (n=12 668) of these participants had a composite outcome event. The highest category of intake of refined grains (≥350 g/day or about 7 servings/day) was associated with higher risk of total mortality (hazard ratio 1.27, 95% confidence interval 1.11 to 1.46; P for trend=0.004), major cardiovascular disease events (1.33, 1.16 to 1.52; P for trend<0.001), and their composite (1.28, 1.15 to 1.42; P for trend<0.001) compared with the lowest category of intake (<50 g/day). Higher intakes of refined grains were associated with higher systolic blood pressure. No significant associations were found between intakes of whole grains or white rice and health outcomes.

Conclusion
High intake of refined grains was associated with higher risk of mortality and major cardiovascular disease events. Globally, lower consumption of refined grains should be considered.
Use of high dose cyproterone acetate and risk of intracranial meningioma in women: cohort study
Authors: Weill Alain , Nguyen Pierre , Labidi Moujahed , Cadier Benjamin , Passeri Thibault , Duranteau Lise , Bernat Anne-Laure , Yoldjian Isabelle , Fontanel Sylvie , Froelich Sébastien , Coste Joël 
Published: February 2021

Abstract

Objective
To assess the risk of meningioma associated with use of high dose cyproterone acetate, a progestogen indicated for clinical hyperandrogenism.

Design
Observational cohort study.

Setting
Data from SNDS, the French administrative healthcare database, between 2007 and 2015.

Participants
253 777 girls and women aged 7-70 years living in France who started cyproterone acetate between 2007 and 2014. Participants had at least one reimbursement for high dose cyproterone acetate and no history of meningioma or benign brain tumour, or long term disease status. Participants were considered to be exposed when they had received a cumulative dose of at least 3 g during the first six months (139 222 participants) and very slightly exposed (control group) when they had received a cumulative dose of less than 3 g (114 555 participants). 10 876 transgender participants (male to female) were included in an additional analysis.

Main outcome measure
Surgery (resection or decompression) or radiotherapy for one or more intracranial meningiomas.

Results
Overall, 69 meningiomas in the exposed group (during 289 544 person years of follow-up) and 20 meningiomas in the control group (during 439 949 person years of follow-up) were treated by surgery or radiotherapy. The incidence of meningioma in the two groups was 23.8 and 4.5 per 100 000 person years, respectively (crude relative risk 5.2, 95% confidence interval 3.2 to 8.6; adjusted hazard ratio 6.6, 95% confidence interval 4.0 to 11.1). The adjusted hazard ratio for a cumulative dose of cyproterone acetate of more than 60 g was 21.7 (10.8 to 43.5). After discontinuation of cyproterone acetate for one year, the risk of meningioma in the exposed group was 1.8-fold higher (1.0 to 3.2) than in the control group. In a complementary analysis, 463 women with meningioma were observed among 123 997 already using cyproterone acetate in 2006 (risk of 383 per 100 000 person years in the group with the highest exposure in terms of cumulative dose). Meningiomas located in the anterior skull base and middle skull base, particularly the medial third of the middle skull base, involving the spheno-orbital region, appeared to be specific to cyproterone acetate. An additional analysis of transgender participants showed a high risk of meningioma (three per 14 460 person years; 20.7 per 100 000 person years).

Conclusions
A strong dose-effect relation was observed between use of cyproterone acetate and risk of intracranial meningiomas. A noticeable reduction in risk was observed after discontinuation of treatment.