Investigation of the multi-physics of laser-induced ignition of transportation fuels

Cleaner and more efficient combustion systems are expected to operate at conditions where successful spark ignition is difficult to achieve. Laser ignition is a proposed alternative ignition system capable of stable engine performance under these conditions. Fundamental studies are needed to fully characterize the complex, multi-physics nature of the laser ignition process. This thesis is a contribution in that direction, also characterizing the ignition and flame behavior of some engine-relevant fuels. This work investigates experimentally the early stages of the laser ignition process, characterizing breakdown and laser-induced shock waves. It then explores self-sustained flame behavior from early flame emergence to complete propagation or quenching. Regarding the early stages of laser ignition, the influence of focusing optics, thermodynamic conditions, and chemical structure of fuels on optical breakdown threshold is examined. These results are presented in a universal representation of the breakdown threshold, facilitating their comparison. The results agree with previous studies and new data sets are generated. Thermomechanical differences between breakdown in non-reactive and reactive mixtures are quantified, isolating the effect of exothermicity on plasma and shock wave propagation. The thermodynamic conditions of the gas near the focal volume are investigated and quantified using two-color interferometry. This information is applied toward developing accurate initial conditions for simulations based on absorbed laser energy and early kernel geometry. With respect to flame propagation, schlieren and interferometric imaging techniques are used to examine early flame behavior, especially near flammability limits. This provides insight into the mechanisms controlling quenching of fuel-lean laser ignited flames as well as the time-scales involved. Four fuels (methane, biogas, iso-octane, and E85) are characterized, highlighting thermochemical effects which control their flame kernel development, the dynamics, and fate of initially sustained flames. Laser ignition is further put into context by contrasting with the better established spark ignition process. The duration of energy deposition and heat transfer to the spark plug electrodes are found to be the main reasons for differences between laser and spark ignited flames. By examining these different physical aspects of laser ignition, this thesis advances understanding of forced ignition, consolidating this by contrasting with spark-ignition behavior. The results are useful for the design of fuel-flexible and lean combustion technologies. The data set is also useful for CFD simulations and simplified modeling of the ignition process

Ideological diversity, hostility, and discrimination in philosophy

Members of the field of philosophy have, just as other people, political convictions or, as psychologists call them, ideologies. How are different ideologies distributed and perceived in the field? Using the familiar distinction between the political left and right, we surveyed an international sample of 794 subjects in philosophy. We found that survey participants clearly leaned left (75%), while right-leaning individuals (14%) and moderates (11%) were underrepresented. Moreover, and strikingly, across the political spectrum, from very left-leaning individuals and moderates to very right-leaning individuals, participants reported experiencing ideological hostility in the field, occasionally even from those from their own side of the political spectrum. Finally, while about half of the subjects believed that discrimination against left- or right-leaning individuals in the field is not justified, a significant minority displayed an explicit willingness to discriminate against colleagues with the opposite ideology. Our findings are both surprising and important, because a commitment to tolerance and equality is widespread in philosophy, and there is reason to think that ideological similarity, hostility, and discrimination undermine reliable belief formation in many areas of the discipline

Identifying Associations between Religious Commitment and Preventive Health Behaviors in a Southeastern Rural County

Health disparities within the United States (US) are continuing to impact ethnic minorities living in rural areas nationwide. In response, there is growing interest in using faith-based settings as vehicles to deliver much needed disease prevention interventions. However, few studies have identified the relationship between private and public religious commitment, individually, and the behaviors or risk factors associated with chronic disease. The purpose of this study was to observe the association between religious commitment, both private (i.e., time spent trying to grow in one’s religious understanding) and public (i.e., frequency of attendance, time spent in fellowship with others) individually, and levels of physical activity (PA), fruit and vegetable (F&V) consumption, self-efficacy in changing those behaviors, and body mass index (BMI). Self-reported data were gathered from rural church members (≥18 years old) located within a single southeastern US county included in Phase 1 of the Faith, Activity, and Nutrition Dissemination and Implementation (FAN D&I) study. Distributed surveys assessed components of FAN implementation, participation in moderate and vigorous PA, F&V consumption, PA and F&V self-efficacy, demographic and health information, church attendance, and private and public religious commitment. Correlation analyses were performed to determine the strength of association between predictor and outcome variables. Study hypotheses were tested by examining relations between public and private religious commitment (independent variables) and health behaviors with multiple linear and logistic regression models. Mixed models were used to adjust for the clustering of participants within churches. Private and public religious commitment were run in separate models because of collinearity between measures. All models controlled for church randomization assignment, member health rating, education, age, and gender. Participants (n=1,443) were predominantly women (68.75%), African American (88.84%), and, on average, 54.8 15.8 years of age. Roughly half the sample was obese (50.49%), self-reported having high blood pressure (55.86%), and had some college education (49.71%). Private and public religious commitment were not associated with meeting MVPA recommendations, meeting F&V consumption recommendations, or BMI. Both religious commitment measures, however, were moderately and positively associated with F&V (p=\u3c.01) and PA (p=\u3c.01) self-efficacy and negatively associated with physical inactivity (p=.01). Religious service attendance was not associated with any of the study’s outcome variables. Significant relationships between religious commitment and PA self-efficacy, F&V self-efficacy, and physical inactivity suggest that individuals who indicate a higher degree of religious commitment are more likely to believe in their ability to succeed in improving PA and healthy eating behaviors, and are less likely to be physically inactive. This study adds to the scientific literature describing the association between religion/spirituality and increased longevity. Future researchers should use study samples with greater religious commitment variability, use more objective measures for PA participation and comprehensive measures for F&V consumption behaviors, and employ measures separate from religious service attendance to quantify degrees of religiosity

Generation of Hyperentangled Photons Pairs

We experimentally demonstrate the first quantum system entangled in every degree of freedom (hyperentangled). Using pairs of photons produced in spontaneous parametric downconversion, we verify entanglement by observing a Bell-type inequality violation in each degree of freedom: polarization, spatial mode and time-energy. We also produce and characterize maximally hyperentangled states and novel states simultaneously exhibiting both quantum and classical correlations. Finally, we report the tomography of a 2x2x3x3 system (36-dimensional Hilbert space), which we believe is the first reported photonic entangled system of this size to be so characterized.Comment: 5 pages, 3 figures, 1 table, published versio

Exploring the Impact of Service Learning in Haiti on the Cultural Competence of OTD Students

As society trends towards increased cultural diversity, the need for cultural competence in the field of occupational therapy (OT) becomes more acute. Immersion in another culture within the curriculum offers the student an opportunity to put their knowledge into practice and recognize the need to competently interact with members of another culture. This study explored the impact of a service learning trip to Haiti, providing seating and mobility services, on all four factors of cultural intelligence (CQ; i.e., metacognitive CQ, cognitive CQ, motivational CQ, behavioral CQ) for occupational therapy doctoral (OTD) students. Using the cultural intelligence scale (CQS), a one-group pretest-posttest design with a paired-samples t-test (α \u3c 0.05) rejected the null hypotheses to support service learning as a pedagogy which enhanced the four factors of CQ for the sample. With increased emphasis on producing culturally sensitive OTD professionals, service learning projects in a cross-cultural setting as a pedagogy extend beyond skill development (e.g., wheelchair fittings) to building coping strategies for interacting with clients (metacognitive CQ), enhancing knowledge of culture (cognitive CQ), persisting to overcome any cultural barriers (motivational CQ), and building the behavioral repertoire (behavioral CQ) of occupational therapists. Contrasting the results from this study with research into the efficacy of short-term study tours, service learning positively impacts behavioral CQ, whereas short-term study tours do not have the same impact. This article details the service learning project and provides recommendations for future research

Cross-Cultural Service Learning as Pedagogy for Character Development in Occupational Therapy Doctoral Students

Occupational therapists must demonstrate a broad spectrum of knowledge, clinical reasoning skills, and professionalism to be effective practitioners. Development of ethical practice must begin with the educational process to shape character traits as building blocks of moral reasoning. This article puts forth a cross-cultural service learning curricular module as lived experience for development of character traits in occupational therapy students. This mixed methods study investigated lived experience in the form of cross-cultural service learning as a pedagogy for development of character traits, as measured by the CIVIC, necessary to navigate professional ethical standards. Findings suggest a cross-cultural lived experience for occupational therapy doctoral students providing seating and mobility services in Guatemala significantly impacted character traits associated with professional ethical standards. Similar lived experience embedded in an occupational therapy curriculum may contribute to character development to guide ethical practice for the next generation of occupational therapists