bluuebunny/crossref_metadata_2025_split huggingface dataset:
A gentle reminder that mean does not imply modal behavior: Few are in‐group biased in minimal groups
Authors: Sand Anders 
Published: July 2020

Previous research reports that people organized into newly formed, arbitrary groups (i.e., minimal groups) are on average in‐group biased. However, that people on average behave in a certain way does not imply that most people behave that way. Here, I report four studies (n = 224) demonstrating in‐group biased average behaviors driven by a minority of about 30% participants. Further, only 14% reported allocating resources in a group‐biased manner because they “favored the in‐group.” I investigate and discuss how methodological issues related to non‐normally distributed data, not taking participants’ intentions into account, and using fixed response matrices can lead to overestimations of how widespread in‐group bias is in minimal groups.
Objective assessment of skin microcirculation using a smartphone camera
Authors: Tesselaar Erik , Farnebo Simon 
Published: July 2020

AbstractBackgroundExisting techniques for assessment of microcirculation are limited by their large size and high costs and are often not so easy to use. Advances in mobile technology have enabled great improvements in smartphone sensor technology. In this study, we used SkinSight, an app for iPhone and iPad, to measure changes in skin microcirculation during physiological provocations. The system estimates changes in the concentration of hemoglobin in the skin by analyzing the reflected light emitted from the built‐in light‐emitting diode and detected by the camera of the smartphone.MethodsA relative hemoglobin (Hb) index was measured during a 5‐min arterial occlusion, post‐occlusive reactive hyperemia, and a 5‐min venous occlusion in 10 healthy subjects, on two separate days. The index was calculated in an area of the skin from the color information in the images acquired by the phone camera. Polarized light spectroscopy imaging was used to measure changes in red blood cell concentration for comparison.ResultsDuring arterial occlusion, relative Hb index was unchanged compared to baseline (P = .40). After release of the cuff, a sudden 60%‐75% increase in Hb index was observed (P < .001) followed by a gradual return to baseline. During venous occlusion, Hb index increased by 80% (P < .001) followed by a gradual decrease to baseline after reperfusion. Day‐to‐day reproducibility of the relative Hb index was excellent (ICC: 0.92, r = 0.94), although relative Hb index was consistently higher during the second day, possibly as a result of changed lighting conditions or calibration issues.ConclusionMicrovascular responses to physiological provocations in the skin can be accurately and reproducibly measured using a smartphone application. Although the system offers a handheld, easy to use and flexible technique for skin microvascular assessment, the effects of lighting on the measured values and need for calibration need to be further investigated.
How the Alt‐Right Label Informs Political Assessments
Authors: Cluverius John , Banda Kevin K. , Daly Hannah R. 
Published: July 2020

ObjectiveTo determine how the alt‐right label informs how voters assess individuals and political candidates.MethodsWe use a survey experiment with a hypothetical candidate. Along with a control, we vary the ideological label the hypothetical candidate uses, including conservative and alt‐right.ResultsThe alt‐right label leads people to view candidates as holding more right‐leaning ideological and issue positions relative to no label and often—specifically on issues relating to race, gender, and norms—relative to a more explicit conservative label.ConclusionThese results shed light on how citizens come to understand and use new ideological labels and suggest that the alt‐right label conveys context‐specific information that differs from that connected to the conservative label.
Who's an iAddict? A Sociodemographic Exploration of Device Addiction Among American Adults
Authors: Nelson Justin J. , Pieper Christopher M. 
Published: July 2020

ObjectiveIn this study, we explore how daily Internet and social media use are related to feeling addicted to technological devices and describe the sociodemographic indicators of device addiction for U.S. adults.MethodsUsing a nationally representative sample of U.S. adults, we estimate a series of logistic regression analyses predicting device addiction.ResultsWe find that social media use, rather than Internet use alone, is a stronger indicator of device addiction. Women report more addiction than men, and employment and education are both associated with increased addiction. Results describe device addiction as a felt reality for U.S. adults of all ages, while also noting particular social and demographic class characteristics for which these dilemmas may be more acute.Conclusion“iAddiction” appears to be endemic to general conditions of postscarcity and concentrated in those with particularly high situations of ontological security. Directions for constructive theory building in the sociology of technology are elaborated.
Popularity and Visibility Appraisals for Computing Olympic Medal Rankings
Authors: Garcia‐del‐Barrio Pedro , Gomez‐Gonzalez Carlos , Sánchez‐Santos José Manuel 
Published: July 2020

ObjectiveThe ranking of countries in the Olympic Games generates a great deal of interest among analysts, academics, and fans. This article proposes an innovative approach to provide Olympic medals (gold, silver, and bronze) with different weights based on metrics of popularity and media visibility and create an alternative historical ranking.MethodsThe analysis uses “Google Trends” and “MERIT” appraisals to capture content and news articles on the Internet that relate to the different types of metals. Figures on weekly relative search intensity in Google and content in the Internet registered monthly are used to track changes over time and thus to control for differences between Summer and Winter Olympic Games.ResultsThe results show that gold medals gather far more attention than silver and bronze medals. By applying the estimated multiplying factors, we create an alternative historical ranking of countries that shows some relevant changes.ConclusionThe use of weights based on popularity and visibility has managerial implications and opens new avenues for future research.
Semantic‐based urban growth prediction
Authors: Mc Cutchan Marvin , Özdal‐Oktay Simge , Giannopoulos Ioannis 
Published: July 2020

AbstractUrban growth is a spatial process which has a significant impact on the earth’s environment. Research on predicting this complex process makes it therefore especially fruitful for decision‐making on a global scale, as it enables the introduction of more sustainable urban development. This article presents a novel method of urban growth prediction. The method utilizes geospatial semantics in order to predict urban growth for a set of random areas in Europe. For this purpose, a feature space representing geospatial configurations was introduced which embeds semantic information. Data in this feature space was then used to perform deep learning, which ultimately enables the prediction of urban growth with high accuracy. The final results reveal that geospatial semantics hold great potential for spatial prediction tasks.
SpotLight on Dynamics of Individual Learning
Authors: Rahman Roussel , Gray Wayne D. 
Published: July 2020

AbstractAveraging performance over a group of individuals implicitly assumes that there is only one set of methods for accomplishing the task and that all learners acquire those methods in the same sequence. We maintain that the average subject is a mythical beast and, rather than profiling a mythical beast, we ask “how do different people each learn the same complex task?” To answer our question, we use SpotLight—a tool for analyzing changes in individual performance as skill is acquired. Specifically, in this report, we use the SpotLight on 40 scores and measures of performance (some collected at millisecond level, others collected once per game), to investigate the skill acquisition of nine individuals each of whom devoted 31 h to becoming skilled players of the classic cognitive psychology game of Space Fortress (Mané & Donchin, 1989). Turning the SpotLight on our best and worst players reveals patterns of performance plateaus, dips, and leaps. Examining these patterns reveals differences as well as commonalities in the evolution of methods discovered and used by each individual across 31 hours of skill acquisition.
Hits and Errors
Authors: Langston Lee S. 
Published: July 2020

Abstract
The gas turbine industry has had many successes, but this past year it has been dogged by the specter of two great mistakes—one that occurred, and another that is being threatened. Many groups are pushing for the immediate elimination of natural gas as a fuel source, and some jurisdictions have begun to ban new residential gas hook-ups. This study analyzes if it can be avoided and a crisis for a major segment of the gas turbine industry can be averted.
Hybrid Electric Propulsion
Authors: Lents Charles E. 
Published: July 2020

Abstract
Electrified propulsion holds the promise of reducing aviation’s CO2 emissions footprint through three means: access to green grid electric energy, improvements in aircraft performance through new airframe and propulsion system architectures and enabling further optimization of the gas turbine cycle. Charging an aircraft battery pack with green electric energy and using this energy to drive electric propulsors results in a zero emissions vehicle. This is practical for light aircraft and short missions. Boosting a Jet-A burning gas turbine with green electric energy (again stored in a ground charged battery), in either a parallel or series turbo-electric architecture can yield a net reduction in CO2 emissions, as long as the fuel burn required to carry the weight of a discharged battery pack does not overcome the reduction in fuel burn afforded by the ground charged battery. Several studies have indicated that a net savings is possible with cell level energy densities approach ∼ 500 whr/kg, a reasonable target for the 2030 time frame. Electrified propulsion can also enable unique aircraft configurations, employing a veryhigh efficiency prime mover (gas turbine) designed for running only a generator at peak efficiency, and/or distributing the propulsors throughout the aircraft, for improvement in L/D and propulsive efficiency.
Periodically Forced Nonlinear Oscillators With Hysteretic Damping
Authors: Bountis Anastasios , Kaloudis Konstantinos , Spitas Christos 
Published: July 2020

Abstract
We perform a detailed study of the dynamics of a nonlinear, one-dimensional oscillator driven by a periodic force under hysteretic damping, whose linear version was originally proposed and analyzed by Bishop (1955, “The Treatment of Damping Forces in Vibration Theory,” Aeronaut. J., 59(539), pp. 738–742). We first add a small quadratic stiffness term in the constitutive equation and construct the periodic solution of the problem by a systematic perturbation method, neglecting transient terms as t→∞. We then repeat the analysis replacing the quadratic by a cubic term, which does not allow the solutions to escape to infinity. In both cases, we examine the dependence of the amplitude of the periodic solution on the different parameters of the model and discuss the differences with the linear model. We point out certain undesirable features of the solutions, which have also been alluded to in the literature for the linear Bishop's model, but persist in the nonlinear case as well. Finally, we discuss an alternative hysteretic damping oscillator model first proposed by Reid (1956, “Free Vibration and Hysteretic Damping,” Aeronaut. J., 60(544), pp. 283–283), which appears to be free from these difficulties and exhibits remarkably rich dynamical properties when extended in the nonlinear regime.
How Uncertain Is Too Uncertain? Validity Tests for Early Resilient and Risk-Based Design Processes
Authors: Hulse Daniel , Hoyle Christopher , Tumer Irem Y. , Goebel Kai 
Published: July 2020

AbstractA number of risk and resilience-based design methods have been put forward over the years that seek to provide designers the tools to reduce the effects of potential hazards in the early design phase. However, because of the associated high level of uncertainty and low-fidelity design representations, one might justifiably wonder if using a resilient design process in the early design phase will reliably produce useful results that would improve the realized design. This paper provides a testing framework for design processes that determines the validity of the process by quantifying the epistemic uncertainty in the assumptions used to make decisions. This framework uses this quantified uncertainty to test whether three metrics are within desirable bounds: the change in the design when uncertainty is considered, the increase in the expected value of the design, and the cost of choice-related uncertainty. This approach is illustrated using two examples to demonstrate how both discrete and continuous parametric uncertainty can be considered in the testing procedure. These examples show that early design process validity is sensitive to the level of uncertainty and magnitude of design changes, suggesting that while there is a justifiable decision-theoretic case to consider high-level, high-impact design changes during the early design phase, there is less of a case to choose between relatively similar design options because the cost of making the choice under high uncertainty is greater than the expected value improvement from choosing the better design.
Analysis of Leaf Seal Leakage Performance Under the Influence of Manufacturing Variations Using Experiment and Computational Fluid Dynamics
Authors: Griebel Clemens 
Published: July 2020

Abstract
In this paper, test data are combined with results from two different computational fluid dynamics (CFD) models to investigate the leakage performance of leaf seals. Experimental data are gathered for centric rotor position using a rotating test rig at various rotational speeds, inlet pressures, and preswirl velocities. The test results are compared to brush and labyrinth seal leakage data from previous studies and reveal elevated leakage rates of the leaf seal. As the tested leaf seals are subject to thermal leaf deformation from welding during the manufacturing process, the influence of geometry variations within the leaf pack on leakage performance is investigated with the help of numerical simulations. Both a fully resolved leaf model and a modeling approach based on porous media are used. The CFD models are validated based on pressure measurements within the up- and downstream coverplate gaps at three different radii. Both CFD models show good agreement with test data for different inlet parameters. A variation of cold clearance shows moderate influence on leakage and small clearances can be brought into context with hydrodynamic lift-up indicated by experimental leakage data. Much higher sensitivity on leakage mass flow is predicted for variations in leaf spacing at the leaf root and leaf tip. The latter is discussed as an explanation for the measured leakage of the test seal with its manufacturing variations, while the first quantitatively shows optimization potential at the design stage of leaf seals.
Surface Wear Anisotropy in AlSi10Mg Alloy Sample Fabricated by Selective Laser Melting: Effect of Hatch Style, Scan Rotation and Use of Fresh and Recycled Powder
Authors: Mishra Ashish Kumar , Upadhyay Ram Krishna , Kumar Arvind 
Published: July 2020

AbstractAdditive manufacturing (AM) has witnessed substantial growth in recent years due to its excellent manufacturing capabilities and innovative production methodologies. However, the mechanical suitability aspect in terms of material wear has not received much attention yet and needs rigorous assessment. This study investigates the wear anisotropy in an AlSi10Mg alloy sample fabricated by selective laser melting (SLM) technique. Different scanning strategies encompassing the island and the continuous scanning patterns were used in sample manufacturing. The effects of the scanning vector orientation, design pattern, and the island pattern size on the mechanical wear and wear anisotropy have been analyzed in detail. The study also focused upon a comparative investigation of the wear properties at the top and the side surfaces to understand the wear anisotropy in different directions. The samples are fabricated both by the fresh and the recycled powder and the role of powder state is described. The ball-on-disk test is performed to simulate the similar contact applications for marine/automotive components such as bearings. Bearing steel balls are used as a standard sliding counterpart material to investigate the wear properties. The wear microstructure is analyzed by scanning electron microscopy. Overall, the island strategy with 2 mm hatch style and 45 deg scan rotation have achieved better wear resistance and friction coefficient compared with the continuous hatch style. The wear behavior is found to be anisotropic. The Raman spectra validate the presence of silicon and carbon particles on the wear track, which have a significant effect on the tribological properties. The type of particles present in the sliding zone characterizes different wear stages. Wear mechanism is described by considering four parameters, namely, scan pattern, scan vector rotation, type of powder, and the wear measurement direction. Results show that the surface wear rate of samples made by the fresh powder is lower than the recycled powder. However, samples of the recycled powder have friction modifier characteristics. The best wear rate and friction coefficient values are obtained with the island strategy (2 mm hatch, 45 deg scan rotation) in the side plane and are 3.76 × 10−6 mm3/N m, 0.0781, respectively.
Full-Annulus URANS Study on the Transportation of Combustion Inhomogeneity in a Four-Stage Cooled Turbine
Authors: Chi Zhongran , Liu Haiqing , Zang Shusheng , Pan Chengxiong , Jiao Guangyun 
Published: July 2020

Abstract
The inhomogeneity of temperature in a turbine is related to the nonuniform heat release and air injections in combustors. In addition, it is influenced by the interactions between turbine cascades and coolant injections. Temperature inhomogeneity results in nonuniform flow temperature at turbine outlets, which is commonly measured by multiple thermal couples arranged in the azimuthal direction to monitor the operation of a gas turbine engine. Therefore, the investigation of temperature inhomogeneity transportation in a multistage gas turbine should help in detecting and quantifying the over-temperature or flameout of combustors using turbine exhaust temperature. Here the transportation of temperature inhomogeneity inside the four-stage turbine of a 300-MW gas turbine engine was numerically investigated using 3D CFD. The computational domain included all four stages of the turbine, consisting of more than 500 blades and vanes. Realistic components (N2, O2, CO2, and H2O) with variable heat capacities were considered for hot gas and cooling air. Coolants were added to the computational domain through more than 19,000 mass and momentum source terms. his was simple compared to realistic cooling structures. A URANS CFD run with over-temperature/flameout at 6 selected combustors out of 24 was carried out. The temperature distributions at rotor–stator interfaces and the turbine outlet were quantified and characterized by Fourier transformations in the time domain and space domain. It is found that the transport process from the hot-streaks/cold-streaks at the inlet to the outlet is relatively stable. The cold and hot fluid is redistributed in time and space due to the stator and rotor blades, in the region with a large parameter gradient at the inlet, strong unsteady temperature field and composition field appear. The distribution of the exhaust gas composition has a stronger correlation with the inlet temperature distribution and is less susceptible to interference.
Sodium Bicarbonate Supplementation Does Not Improve Running Anaerobic Sprint Test Performance in Semiprofessional Adolescent Soccer Players
Authors: Guimarães Rodrigo dos Santos , de Morais Junior Alcides Correa , Schincaglia Raquel Machado , Saunders Bryan , Pimentel Gustavo Duarte , Mota João Felipe 
Published: July 2020

Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. −0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. −1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.
COVID-19: minimising contaminated aerosol spreading during CPAP treatment
Authors: Donaldsson Snorri , Naver Lars , Jonsson Baldvin , Drevhammar Thomas 
Published: July 2020

BackgroundThe COVID-19 pandemic has raised concern for healthcare workers getting infected via aerosol from non-invasive respiratory support of infants. Attaching filters that remove viral particles in air from the expiratory limb of continuous positive airway pressure (CPAP) devices should theoretically decrease the risk. However, adding filters to the expiratory limb could add to expiratory resistance and thereby increase the imposed work of breathing (WOB).ObjectiveTo evaluate the effects on imposed WOB when attaching filters to the expiratory limb of CPAP devices.MethodsTwo filters were tested on three CPAP systems at two levels of CPAP in a mechanical lung model. Main outcome was imposed WOB.ResultsThere was a minor increase in imposed WOB when attaching the filters. The differences between the two filters were small.ConclusionTo minimise contaminated aerosol generation during CPAP treatment, filters can be attached to expiratory tubing with only a minimal increase in imposed WOB in a non-humidified environment. Care has to be taken to avoid filter obstruction and replace filters as recommended.