Open Research Oklahoma (Oklahoma State Univ.)
Not a member yet
42035 research outputs found
Sort by
Application of an impulse hammer for structural gap detection within composite UAV wings
No full textSenior design project UAV Wings manufactured at the Oklahoma State University Design and Manufacturing Laboratory have had midflight delamination’s due to improperly bonded structure. These structural deficiencies are caused by gaps between the structure and inside composite skin during the bonding process. Current lab techniques implore the use of tap testing wings by hand before bonding to ensure properly fit structure. However, this approach requires significant training and lacks the ability to locate smaller gaps. Automation of testing could turn this qualitative approach into a quantitative one, increasing the ease and reliability of structural fitting. An extensive literature review determined that the application of non-destructive acoustic emission through the use of automated tap testing could be a simplistic yet effect approach. A modally tuned tap hammer could be used to determine the reduced local stiffness caused by structural gaps beneath composite wing skin. In order to investigate the application of a modally tuned tap hammer for structural gap detection, three rounds of eleven experiments were undertaken. The first round of four experiments investigated the applicability of a tap hammer for detecting structural contact through the use of metal beams. Results from this round determined that spectra analysis was not effective, however the force pulse width and maximum magnitude were key indicators of changes in stiffness. The second round of four experiments explored the application of automated tap testing with composite beams. The results demonstrated that lower stiffness of thin composite beams further enabled the proposed automated tap testing approach. The third round of three experiments explored the effects of wing geometry on automated tap testing by examining wing sections with structures that included gaps. The results indicated that shear web gap detection was much more effective than rib structures, however the composite skin thickness and curvature played a major role in the applicability of the automated tap testing approach. Although this method showed promising signs with differences seen in force pulse shape, the resolution of gap detection is rather small due to the lack of reduced local stiffness caused by structural gaps beneath composite wing skin
Advanced investigation of ion diffusion on cementitious materials by using X-ray radiography
No full textThis dissertation discusses the concept of the diffusion coefficient (Dᵢ꜀) and its role in understanding and improving concrete durability. It presents a series of innovative approaches and findings, collectively advancing the knowledge of Dᵢ꜀ in concrete. The first research aspect introduces CHIP (Checking Ion Penetration), a novel application of dental X-ray technology. It refines Dᵢ꜀ measurement in concrete by combining measurements from multiple angles and correcting for X-ray beam hardening, resulting in a 20% increase in accuracy (as indicated by R square) and a remarkable 63% reduction in variability. The second phase offers an expedited Dic testing method that reduces the testing period to under 8 hours of ponding. This approach, using CHIP in an accelerated diffusion test, demonstrates strong correlations (R square equal to 0.96) with conventional diffusion measurements, regardless of age and mix design, potentially simplifying the use of diffusion coefficients in concrete specifications and performance-based designs. The third research focuses on the long-term evolution of Dᵢ꜀. It extends the measurement period to examine the change in Dᵢ꜀ of 17 fly ashes at 20% and 40% replacement levels from 45 to 1000 days. By employing a simplified predictive model based on bulk CaO, SiO₂ , and total equivalent alkalis (Na₂ Oeq) of the fly ash, this work offers an efficient tool for assessing the long-term diffusion coefficient in various fly ash replacement scenarios
Inequities in medically assisted reproduction: A scoping review
No full textIntroduction: Infertility affects one in five women in the United States and may do so regardless of race/ethnicity, socioeconomic status, geographic location, income, or educational status. These factors, however, may play a large role in access to infertility treatments, or medically assisted reproduction (MAR). This scoping review aimed to identify gaps in research pertaining to inequities in MAR, and propose suggestions for future research directions.Methods: This review was conducted following the guidance of the Joanna Briggs Institute methodology for scoping reviews. Searches were performed in July 2022 using MEDLINE (via PubMed) and Ovid Embase, identifying articles for screening. Articles that reported on MAR inequities, published between 2016–2021 in the United States, and written in English were included. Each article’s inequity findings were analyzed, extracted, and reported. The frequencies of the inequities investigated were recorded.Results: Ninety-six articles underwent full-text screening and 66 were included in our sample. Race/ethnicity was the most commonly reported inequity. The majority of the studies focused on MAR outcomes by race/ethnicity, and many found that historically marginalized populations had worse outcomes. Since the NIH’s classification of Sexual and Gender Minorities as a health disparity population in 2016, 15 articles within our sample investigated LGBTQ+ inequities in MAR. Historically marginalized populations were less likely to use MAR or seek infertility care and findings were similar among LGBTQ+ populations. The majority of studies found positive correlations with MAR use with income and education. The least commonly studied inequities in our sample were sex or gender and rural/under-resourced populations; findings showed that men and people from rural/under-resourced populations were less likely to access MAR. Studies that examined occupational status had varying findings.Conclusion: Our study identified research gaps regarding MAR within each of the inequities examined, though some gaps were more prominent than others. We suggest that future research be targeted toward: (1) standardizing and diversifying race/ethnicity reporting regarding MAR, (2) increasing access to infertility care for LGBTQ+ populations by providing more inclusive care, (3) increasing access to infertility care for men, and (4) increasing access to MAR for rural/under-represented populations by identifying logistic challenges
Edmond multi-modal transport hub
No full textIn my design proposal for the Edmond Multi-Modal Transport Hub, our primary focus was not on the development of a new monument for the city, but of a revival and recontextualization of the existing Rodkey Flour Mill as an icon for the city along with our project. My proposal aims not to compete with the existing flour mill but complement it in formal expression. However, it is important that it stands out as a distinctly new object, in direct contrast with the surrounding historic downtown. My goal is to redefine the public's association with these objects, and create a space where people are now allowed to interact with these historic forms in a way that allows them to build an appreciation for their towns past
Identifying trajectories and predictors of depressive symptoms among individuals with asthma: An application of latent growth curve modeling
No full textIntroduction: Among the general population, depressive symptom trajectories demonstrate a curvilinear pattern of change across adolescence and into adulthood, with more depressive symptoms during adolescence and adulthood. Individuals with chronic medical conditions experience worse trajectories of depressive symptoms (e.g., faster acceleration, slower deceleration of symptoms); however, no studies have examined depressive symptoms trajectories among individuals with asthma. Youth with comorbid asthma and depression experience increased asthma morbidity, systematic inflammation, and healthcare utilization. This study expanded prior literature by identifying the following among individuals with pediatric asthma: 1) longitudinal depressive symptom trajectories across adolescence and into adulthood and 2) predictors of baseline levels and changes in depressive symptoms across time.Methods: Participants included 965 adolescents from the National Longitudinal Study of Adolescent to Adult Health with asthma at baseline. Adolescents self-reported on depressive symptoms (CESD-9) across four assessments (W1=7-12th grade, W2=1 year later, W3 =18-26 years old, W4=24-32 years old). Baseline demographics (sex, ethnicity/ race, age, parent education, neighborhood poverty) and the persistence of asthma at W3 (past year asthma medication usage) were included as covariates. Latent growth curve modeling was used to identify depressive symptom trajectories and their predictors. Standardized regression coefficients are presented.Results: A quadratic model was the best fitting unconditional model (Mintercept= 5.73, p<.00; Mlinear= -.38, p<.001; Mquad= .03, p<.001), with a linear deceleration in depressive symptoms during adolescence and an acceleration of symptoms into adulthood. Female sex (B=0.58, p<.001), parents having less than a high school degree (B= -.57, p<.001), older age (B=.19, p<.001), and identifying as Black (B=.31, p=.04) were associated with greater baseline depressive symptoms. Older individuals exhibited faster linear symptom decelerations (B=-.56, p<.001) and faster symptom accelerations (B=.73, p<.001). American Indian individuals exhibited faster linear symptom decelerations (B=-1.98, p=.005) and faster quadratic accelerations (B=3.33, p=.007).Discussion: Our results suggest that the depressive symptom trajectories of individuals with asthma are curvilinear, which is similar to the pattern among individuals without asthma. Socioeconomic disadvantage (lower parent education) and racial marginalization (for Black youth) were associated with greater baseline depressive symptoms. Although American Indian youth demonstrated more favorable trajectories in adolescence (faster symptom deceleration), they also exhibited worse trajectories across young adulthood and adulthood (faster symptom acceleration). These findings suggest the need to better understand the impact of multilevel risk and protective factors (e.g., social determinants of health) on depressive symptoms trajectories for individuals with asthma, especially marginalized populations
Experimental wake survey of low Reynolds number wind tunnel
No full textThis poster presents the integration of a mechanical traverse and multi-hole probe for use in low Reynolds number wake surveys. Advanced testing equipment offers enhanced data processing and visualization of three-dimensional flow for wind tunnel wake surveys. The traverse and probe instrumentation can be used in many studies including research regarding advanced propeller designs for small unmanned aerial systems or upstream flow validation. This research project aims to integrate a traverse and multi-hole probe into existing LabVIEW framework in the ATRC 058 wind tunnel. The advantage to using LabVIEW rather than other data acquisition software is its intuitive visual interface and use of user inputs and automated controls. An Isel iMC-S8 controller and LES 5 linear actuator allow for full cross-sectional wake surveys while an Aeroprobe multi hole probe and air data computer stream angular flow data to the central computer. The integration of these systems allow for accurate real time measurements to be visualized and recorded directly into LabVIEW which can then be processed with MATLAB to provide informative data visualization.Mechanical and Aerospace Engineerin
Retro fit kit to the exhaust of a JetCat P100 for electrical power generation
No full textThis paper presents the design and analysis of a power generator retro fit kit that bolts on a JetCat P100 in place of the stock nozzle. The motivation for this study is for small high-speed aircraft that would benefit from a power supply to their payload. The approach to this study was to first create a cycle analysis to determine the restraints and characteristics of the flow through the stock JetCat P100. From this analysis it was determined that the optimal place to extract power is from the exhaust, since the exhaust has the highest mass flow rate potential to be harvested from. Finally, detailed drawings of each component were made and analyzed. The final design is a power turbine in the nozzle that is connected to a generator through a gear box. When the exhaust flow spools up the turbine, the generator will produce an AC current. This current will go through a rectifier converting it into DC current that can be stored in a battery. This set up will produce an excess of 500 watts of power when the engine is running at full throttle. Observation from this study can inform potential aircraft and engine designers for small high-speed aircrafts
Nature of goal blocking: Investigating when experienced CWBI leads to direct and displaced CWBI
No full textThe frustration-aggression hypothesis (Dollard et al., 1939) states that blocked goals caused by an instigator (i.e., an individual, organization, circumstance) leads to frustration which generally causes employees to aggress directly toward the instigator, or, if there is a threat of retaliation from the instigator, to aggress indirectly. The indirect response may include displacing aggression onto an alternative target at work (e.g., coworkers) or at home toward family and friends (Hoobler and Brass, 2006; Liu et al., 2015; Porath and Pearson, 2012). However, what is unclear is specifically what blocked goals lead to direct or displaced negative behaviors. Additionally, whereas research has only focused on threat of retaliation of the instigator, little attention has been paid to the threat that displaced targets may or may not hold. My dissertation begins with a pilot study to establish which blocked goals commonly lead to a particular form of negative workplace behavior, individually-directed counterproductive work behavior (CWBI). I then conduct a second pilot study in order to test the daily prevalence of experienced CWBI as well as the targets of employees’ instigated CWBI (direct versus displaced). I conducted an ESM study to test my model. My results indicate that blocked goals about self (i.e. identity threat) and blocked goals about work (i.e. work interference) both contribute to employee’s choice to engage in displaced CWBI. Additionally, my results indicate that the threat of retaliation of the displaced target is an important factor in employee’s choice to engage in displaced CWBI. My dissertation expands upon the frustration-aggression hypothesis by furthering our understanding of when experienced CWBI leads to CWBI in response by creating an understanding of the nature of the blocked goals that lead to negative emotions and ultimately CWBI, as well as considering the threat of retaliation of displaced targets
Evaluation of experimental greens-type hybrid bermudagrass selections by genetic profiling, morphological measurements, and field testing
No full textThe lack of genetic diversity among ultradwarf bermudagrasses [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy] used throughout the southern region and transition zone in the United States is well known. To find genotypes with improvements in areas where ultradwarfs are generally lacking, new genetics must be introduced through traditional crosses. Oklahoma State University has developed multiple genotypes from cold-hardy parent materials for use as putting green surfaces. This research was conducted to quantify the genetic and morphological diversity among these new genotypes and ultradwarf cultivars for comparison, as well as evaluate the performance of these genotypes under putting green management. An additional objective of this research was to evaluate the performance of vegetation indices collected by unmanned aerial systems to estimate the percent canopy coverage of advanced phenotyping trials during and after establishment. Results showed there was significant genetic diversity between the new genotypes and the ultradwarf cultivars, while the latter showed very high genetic similarity to one another. Additionally, there was a significant difference among the morphological characteristics measured in this study in both the field and greenhouse trials. While the new genotypes were genetically distinct from the ultradwarfs, some showed similar morphological characteristics. The putting green field trial showed none of the new genotypes demonstrated similar ball roll distance to standard ‘TifEagle’, but several genotypes including OKC0920, OKC3920, 11x2, 19x19, and MSB1050 demonstrated similar or improved visual characteristics and rooting depth. A significant relationship between leaf blade length and ball roll distance for the genotypes used in this study was found which could assist breeders in making future selections. For the remote sensing methods, there was a significant relationship present between each of the methods and the logit transformed percent green cover. However, there was a significant difference between the two establishment periods. These indices may be best suited for use on their own and not estimation of percent green cover. Information collected in this research may assist in the introduction of new genotypes for use on putting green surfaces
Higher inequality increases the gap in the perceived merit of the rich and poor
No full textThe rewards people receive are often taken as indirect evidence of their merit. We outline an argument that addresses how the magnitude of macrolevel income inequalities affects perceptions of the distribution of merit in a society. We propose that higher levels of economic inequality will lead to perceptions of greater differences in merit such that societies with higher inequality will be characterized by a larger “merit gap,” namely, larger differences in the perceived merit of the rich and poor. We test these arguments using an online experiment that manipulated the level of inequality (high vs. low) in an anonymized society. Participants perceived a larger merit gap in high versus low inequality societies. Our arguments and findings have implications for attitudes about inequality and redistributive policies.Sociolog