16789 research outputs found
Sort by
The Effects of Lamina Stacking Sequence on the Structural Response of Composite Laminates
No full textComposites are lightweight engineered materials made of fiber and matrix. The fiber acts as the reinforcement, while the matrix holds the fibers together. Fiber-reinforced composite laminates are prepared by stacking single sheets of continuous fibers, called lamina or ply, in different orientations to achieve the desired strength and stiffness. The Lamina Stacking Sequence (LSS) represents the order these layers are stacked in a composite laminate. This research aims to numerically and experimentally investigate the effects of LSS on the structural response of composite laminates. For example, the [0/45/-45]s laminate represents a symmetric composite plate consisting of 6 laminae stacked at 0, 45, -45, -45, 45 and 0 degree orientations. These orientations ([0/45/-45]s, [0/-45/45]s, [45/-45/0]s, [-45/45/0]s, [45/0/-45]s, and [-45/0/45]s) represent the same laminate but with different LSS. In our research, we performed numerical simulations using the finite element analysis software ANSYS to study the structural response of a composite laminate defined by [0/45/-45]s with several LSS. We used the material properties of graphite and epoxy to simulate the fiber and matrix, respectively. These laminates were subjected to axial and bending loads to observe their structural response. Each laminate experienced the same stress and deformation when subjected to axial loads, but the results varied between LSS when subjected to bending loads. To verify these results, we performed experiments by printing composite laminates using PETG embedded with chopped carbon fiber. The tensile response of these laminates was found to be mostly consistent and invariant with LSS under axial loading
To Play or Not To Play: Investigating the Effects of Auditory Stimuli During Running
Full text linkResearch has shown that listening to music during physical activity can have a positive effect on emotional state, ratings of perceived exertion, and overall performance. However, limited research has investigated the differences between tempo-matched music and metronome pacing on running performance. Many runners utilize metronome pacing to pace a run, improve efficiency, and enhance form. To date, research on the efficacy of metronome pacing compared to music on one mile run time to completion is limited. PURPOSE: To determine the effects of different auditory stimuli (e.g., music, metronome, and silence) on one mile run time in young adults. METHODS: Young adults (n = 11; 21.3 ± 4.1 y) who were free from any previous or existing hearing impairments volunteered for the study. Participants ran one mile under each of the three conditions (music, metronome pacing, and silence), in a randomized and counterbalanced order, and separated by at least 48 hours. The music and metronome-pacing conditions were tempo-matched at 150 bpm. Time to completion was recorded for the one mile run and is reported as mean ± SD. Data were analyzed using a one-way repeated measures ANOVA with an alpha level set at 0.05. RESULTS: There was a significant difference in time to completion for one mile across the three conditions (p = .008; h2 = .38). Time to completion was shorter with music (8.89 ± 1.36 minutes) than silence (9.29 ± 1.41 minutes; p = .002). However, there was no difference between music and metronome pacing (9.15 ± 1.65 minutes; p = .13) or between metronome pacing and silence (p \u3e .99). CONCLUSIONS: Our findings indicate that running while listening to music at 150 bpm results in shorter time to completion compared to tempo-matched metronome pacing and silence. This suggests that factors other than the tempo may contribute to performance improvements. The current study was limited to young, healthy adults, limiting the generalizability to other groups such as older adults and runners aiming to rehabilitate gait patterns. Therefore, future research should investigate whether music or tempo-matched metronome pacing is superior for improving efficiency and enhancing form
That Movie Changed Me! Effect of Induced Mood on Story Interpretation
Full text linkStudies have found that mood can affect a variety of aspects of cognition, such as memory, comprehension, and decision making. In one such study, participants identified with the character that reflected their hypnotically induced mood, and in another, story endings that were incongruent with the film clip-induced mood were more difficult to process. In the current study, film clips were used to induce moods, and participants were asked to write an ending to an ambiguous story. The prediction is that participants’ completions will reflect their induced mood. To date, 25 Eastern Washington University undergraduate students have been recruited and screened for symptoms of depression with the CES-D; only the 10 participants (Ps) with a score ≤ 15 were included. They were randomly assigned to watch one of four mood induction film clips: fear (Halloween), happiness (An Officer and a Gentleman), sadness (The Champ), or neutral (The Last Emperor). The mood induction was verified with a 9 point scale that assessed the degree of intensity of emotion, and Chi-squared was computed for each film clip; only fear and sadness were successfully induced, largely because Ps who saw the happy clip split their mood ratings between amusement and neutral. A brief ambiguous story was provided, and Ps were instructed to complete the story with a few sentences that explain something about the characters, what happens next, and how the story ends. The written endings were coded by three observers for mood expressed, and they were consistent with the mood of the film clip viewed (Chi-squared (6, 10) =16.00, p=.014). The continuation of data collection should result in stronger results as our participant pool increases. If the hypothesis continues to be supported by incoming data, this will add to previous studies that have shown that mood serves as context for processing information
Pseudo-vampires in the Nineteenth-Century English vampire canon: draining life force by class
Full text linkExamining the effects of wearable technology and biometric coaching on heart rate variability, health related quality of life, and predictors of heart rate variability in collegiate athletes
No full textObjective: To determine the effects of a wearable plus personalized biometric-based coaching on heart rate variability (HRV) and health-related quality of life (HRQoL). Participants: Student athletes on NCAA Division I Eastern Washington University football team. Methods: A mixed study design including randomization of participants into a wearable without coaching group (WO) and a wearable with coaching group (WC). HRV data were recorded via WHOOP® strap for 14 weeks. WC group received personalized coaching based on HRV data via smart phone application. Student athletes completed a HRQoL survey at start and end of study. Results: A significant effect of time was present for both HRV and HRQoL. A slightly larger increase was seen in both variables for the WC group; however, group means were not significantly different. Conclusions: Access to biometric data alone may imbue an increase in HRV and HRQoL. Such increases may be compounded by a reduction in both training and academic stressors during the summer term off-season.
Objective: To determine if sleep metrics and group assignment between wearable plus coaching (WC) and wearable without coaching (WO) are predictive of HRV in NCAA DI football players. Participants: Collegiate student athletes on NCAA Division I football team. Methods: Participants were randomized into WC and WO groups. HRV and restorative sleep stages were recorded via WHOOP® 4.0 strap for 14 weeks. The percentage of sleep duration dubbed restorative sleep (%RESTOR) was calculated. Linear forced entry regression analysis was performed to determine the association between %RESTOR, group assignment, and HRV. Results: %RESTOR and group assignment accounted for 59.3% of the variance seen in HRV. A significant, negative association between %RESTOR and HRV was present. Group assignment was not associated with HRV. Conclusions: Lower %RESTOR was indicative of higher HRV. Less time spent in restorative sleep may indicate less stress and less need for recovery
