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A New Empirical Law for the Prediction of the Zero-Lift Pitching Moment Coefficient of Swept and Tapered Wings
Get PDFA new empirical law for the prediction of the zero-lift pitching moment coefficient of trapezoidal wings with linear twist and constant taper and sweep in subsonic flow is introduced. This law is quite general in that it does not rely on the use of charts and spans the normal range of values of taper ratio, aspect ratio, and sweep for subsonic aircraft. It does not, however, accommodate different airfoils along the wingspan and only positive sweep has been considered. The empirical law was first derived for the incompressible regime and then an additional empirical law for the compressibility effect has been provided. The results compare favorably with experimental data for straight wings and with some pre-existing empirical methods for wings with low to moderate sweep. It is also shown that the most widely used method of estimating the zero-lift pitching moment coefficient is highly inaccurate
Toward HMoob-centered Inquiries: Reclaiming HMoob American Educational Scholarship and Curriculum
Get PDFAs the intersecting field of HMoob (Hmong/Mong) Studies/Hmong American Studies, Southeast Asian American Studies, and Education Studies grow, there is also an increased desire to learn, read, and produce scholarship by HMoob people. Throughout our graduate journeys and as early career scholars and educators at the intersections of Critical HMoob Studies and Education Studies, we—Choua and Kaozong—have yearned for scholarship on HMoob that is not just about representation but includes research that recognizes HMoob strengths and assets. Specifically, we craved scholarly knowledge that employed HMoob assets to interrogate racist, colonial discourses and decenter whiteness. This special issue centers HMoob (Hmong/Mong) epistemologies and ontologies in HMoob American education research to produce “new narratives and imaginaries” (Vue & Mouavangsou, 2021, p. 273). We aim to provide empirical, theoretical, epistemological, ontological, and methodological HMoob-centered approaches in scholarship and curriculum building. While there are existing scholarships that aim to understand and advocate for HMoob American education, we call for a critical analysis of this genealogy. HMoob scholarship, especially those that seek social justice change, should not be grounded nor should it produce deficit and/or damage-centered discourses on the communities it is advocating for
War and Peace. The Film Iconeme of the Urban Square as Image of Europe in Transition (1944-1948)
Get PDFA central feature of European urban landscapes, the square represents the public space par excellence. At the end of WW2 and in the immediate postwar time, the role of cinema in representing and reimagining urban squares was crucial. Through film images, they became the stage and the mirror of a Europe in transition. This contribution, examining Italian, French, German, and Czechoslovak cases, posits the square as an essential iconeme in postwar nonfiction cinema and visual culture, acting as a fil rouge to visually retrace the path of Europe from war to peace, and into new forms of political tension
Influence of a Phytogenic Feed Additive on Broiler Chicken Behavior and Welfare
No full textBroiler chickens are routinely exposed to various conditions, such as heat stress and stocking density, which may negatively influence their welfare status. This study examined the influence of a commercially available proprietary phytogenic feed additive (Probiotech International, Inc.) on welfare measures, environmental measures, productivity, body temperature, and behavior of commercial broiler chickens. Two flocks (Trials 1 & 2) utilized a total of 1,650 Ross 708 broilers housed in two separate rooms with floor pens at Purdue University’s ASREC Poultry Unit.Trial 1 birds (n = 750) were divided into 20 separate pens (5 pens/treatment): PHD: phytogenic supplementation and raised at standard industry stocking density (37 kg/m²), PLD: phytogenic supplementation and raised at a lowered stocking density (27 kg/m²), CHD: control diet and raised at standard industry stocking density, and CLD: control diet and raised at a lowered stocking density. Due to the aromatic properties of the phytogenic additive, PHD and PLD birds were housed in one room and CHD and CLD birds were housed in another room. The feed supplement was mixed in at an inclusion rate of 0.25 g/kg. Phytogenic supplementation began at 15 d, coinciding with feeding the grower diet, and continued until 42 d when the study concluded. Heat stress was applied to all birds from 30 to 32 d, where the peak temperature did not exceed 34.4ºC. Welfare measures (gait, footpad dermatitis, hock burn, and feather cleanliness) and litter quality were assessed at 27 d and 39 d. Ammonia concentrations were measured at 35 d and 39 d. Productivity (body weight, feed intake, and feed conversion ratio) was measured weekly. Body temperature via thermography of the eye surface was collected at 29, 32, and 34 d. Behavior data were collected at the following periods for 2 continuous days: 23-24 d (Period 1), 31-32 d (Period 2), and 36-37 d (Period 3).Trial 2 birds (n = 900) were assigned to 25 separate pens (5 pens/treatment) with the same groups as Trial 1, with an additional group (MHD): control diet, housed in the same room as PHD and PLD birds, and raised at standard industry stocking density. Phytogenic supplementation was provided as in Trial 1. Heat stress was again applied to all treatments from 30 to 32 d, where the peak temperature did not exceed 31ºC. Welfare measures and litter quality were collected at 27 d and 38 d. Ammonia concentrations were measured at 27, 31, and 38 d. Productivity was measured from 15 d to 27 d (grower phase), and 27 d to 38 d (finisher phase). Body temperature via cloacal temperature recording occurred at 29, 31, and 33 d.Welfare data and litter quality were analyzed using PROC LOGISTIC (SAS 9.4); productivity data were analyzed using PROC MIXED (SAS 9.4); behavior data were analyzed using PROC GLIMMIX (SAS 9.4); and eye surface temperature, cloacal temperature, and ammonia concentration were analyzed using a nested mixed model found in the afex package using R (version 4.2.1) and R Studio (R Foundation for Statistical Computing). All statistical differences were considered significant when P \u3c 0.05. Results of Trial 1 indicated that phytogenic supplementation significantly influenced hock burn and feather cleanliness, body weight and feed conversion ratio, ammonia concentration, as well as Period 1 sitting, Period 2 drinking, preening, standing, and wing spreading, and Period 3 drinking, preening, sitting, standing, and walking behaviors. Results of Trial 2 indicated that diet had no effect on any measured parameter. The variation in results suggests that factors such as stocking density or management strategies influenced the measured parameters, rather than diet alone. More research is needed to understand the specific effects of phytogenic feed additives, social and environmental stressors and whether phytogenic feed additives can improve bird performance and welfare under longer heat stress periods
The Role of Digital Nudges in Engineering Students’ Engagement with an Educational Mobile Application
No full textThe proliferation of digital educational applications (apps) has revolutionized the pedagogical landscape for students and instructors, both within and beyond the confines of traditional classrooms. Educational apps offer a variety of features that can help students learn more effectively, including personalized instruction and real-time feedback. However, some studies have found that students may not be engaging with the apps regularly or for extended periods of time. This lack of engagement can limit the apps’ potential to improve student learning. Consequently, researchers have investigated methods to enhance students’ app engagement, including the use of digital nudges. Digital nudging is a strategy that proposes utilizing small, nonintrusive cues that capitalize on individuals’ cognitive biases to influence their behavior.This dissertation makes a significant contribution to ongoing efforts by examining the effectiveness of nudge-based digital interventions in improving students’ engagement with the CourseMIRROR educational app. CourseMIRROR is an educational mobile app that prompts students to reflect on the interesting and confusing aspects of lectures throughout a semester. The CourseMIRROR app uses Natural Language Processing (NLP) algorithms to 1) scaffold the students while generating reflections and 2) summarize the students’ submitted reflections. This study focuses on designing digital nudges to improve students’ cognitive and behavioral engagement with specific features of the app that are crucial to achieving its primary purposes. These primary purposes include 1) facilitating students to submit reflections, 2) enabling students to view the reflection summary interface, and 3) scaffolding students to write in-depth and comprehensive reflections. The study consists of three experiments investigating the effectiveness of these digital nudges for improving student engagement with the CourseMIRROR app.For this dissertation, I conducted three experiments by implementing the CourseMIRROR app in multiple sections of a first-year engineering course at Purdue University over a semester. Experiment 1investigated the impact of social comparison nudge and neutral reminder nudge to increase students’ reflection submissions by using the app. Students were randomly assigned to one of three conditions: social comparison nudge, neutral reminder nudge, or baseline (no nudge). The social comparison nudge involved reminding and showing peers’ behavior through their reflection submissions, and the neutral reminder nudge involved sending automated reminders to students to submit their reflections. The results indicated that social comparison and neutral reminder nudges were effective in increasing reflection submissions compared to the baseline condition. However, the social comparison nudge was slightly more effective in improving the number of reflection submissions than the neutral reminder nudge. Also, the nudge interventions became effective in increasing the reflection submissions by refocusing the students’ attention as time progressed in the semester.Experiment 2explored the impact of summary reminder nudges and interface nudges to increase students’ visits to the reflection summary interface in the app. Students were randomly assigned to summary reminder nudge, interface nudge, or baseline conditions. The summary reminder nudge involved reminding students to visit the reflection summary interface in the app. The interface nudge involved making the summary available lecture more prominent to draw students’ attention to the reflection summary interface
An Improved Airflow and Watering Balance for a Biowall
No full textClean indoor air is a necessity, in the past opening a window or supplying outdoor air would suffice for removing indoor contaminated air. As humans live in more dense neighborhoods or urban areas, the need for energy efficient clean indoor air is important. As outdoor air pollution increases, a Biowall is a device to improve aesthetics and clean indoor air by pulling air through the root zone of plants in a loosely packed growth media. The Biowall is a sustainable supplement to a single use air filter. For this research a small Biowall was designed, fabricated, tested, and installed in the Children’s wing of a public library. The airflow simulation and watering for the Biowall was explored using Autodesk CFD to simulate the airflow through growth media and identify a hole pattern to distribute airflow evenly through the plant trays. Various watering line designs were also tested until the rectangular design proved to be more balanced at distributing the water evenly to the growth media. Finally, the air cleaning ability of the Biowall was tested using a Clean Air Delivery Rate (CADR) test to quantify the cleaning rate. The Biowall provided 12 cfm of clean air, or about 2 cfm/sq ft of plant tray area
A Portfolio Approach to Grain Marketing and Crop Insurance Strategies for an Indiana Case Farm
No full textWhile many studies have evaluated corn and soybean marketing strategies and crop insurance coverage levels separately, few studies have examined their interactions simultaneously. This study evaluated the risk return tradeoff between marketing and crop insurance strategies in a portfolio context. The Target MOTAD model was the primary method used to explore the tradeoffs between expected returns and downside risk. On average, the hedge and roll strategy had the highest net return over the 30-year period for both corn and soybeans. When corn and soybeans were evaluated separately, results indicated that the optimal combination of marketing strategies was not dependent on crop insurance coverage levels. The strategies contributing to an optimal portfolio for corn were a mixture of the hedge and roll strategy, and the marketing year cash price strategy. Combining the hedge and roll strategy with the marketing year cash price strategy was also optimal for soybeans. When corn and soybean strategies were optimized simultaneously, however, optimal marketing strategies were dependent on the crop insurance coverage level chosen. The optimal marketing strategies to mitigate risk for the 75 and 80 percent revenue protection plan included the corn hedge and roll strategy, the soybean marketing year cash price strategy, and the soybean six-month cash price strategy. For the 85 percent revenue protection plan, the optimal marketing strategies were the corn hedge and roll strategy, soybean marketing year cash price strategy, and the soybean hedge and roll strategy. For the 90 and 95 percent supplemental coverage option (SCO) and enhanced coverage option (ECO) plans, the optimal marketing strategies were the corn marketing year cash price, the corn hedge and roll, and the soybean six-month cash price strategy
VR-Based Testing Bed for Pedestrian Behavior Prediction Algorithms
No full textUpon introducing semi- and fully automated vehicles on the road, drivers will be reluctant to focus on the traffic interaction and rely on the vehicles\u27 decision-making. However, encountering pedestrians still poses a significant difficulty for modern automated driving technologies. Considering the high-level complexity in human behavior modeling to solve a real-world problem, deep-learning algorithms trained from naturalistic data have become promising solutions. Nevertheless, although developing such algorithms is achievable based on scene data collection and driver knowledge extraction, evaluation remains challenging due to the potential crash risks and limitations in acquiring ground-truth intention changes.This study proposes a VR-based testing bed to evaluate real-time pedestrian intention algorithms as VR simulators are recognized for their affordability and adaptability in producing a variety of traffic situations, and it is more reliable to conduct human-factor research in autonomous cars. The pedestrian wears the head-mounted headset or uses the keyboard input and makes decisions in accordance with the circumstances. The simulator has added a credible and robust experience, essential for exhibiting the real-time behavior of the pedestrian. While crossing the road, there exists uncertainty associated with pedestrian intention. Our simulator will anticipate the crossing intention with consideration of the ambiguity of the pedestrian behavior. The case study has been performed over multiple subjects in several crossing conditions based on day-today life activities. It can be inferred from the study outcomes that the pedestrian intention can be precisely inferred using this VR-based simulator. However, depending on the speed of the car and the distance between the vehicle and the pedestrian, the accuracy of the prediction can differ considerably in some cases
Indianapolis GEMS Club: Engagement in Informal Mathematics and Science Learning
Get PDFThere continues to be a need for the representation of women in science, technology, engineering, and mathematics (STEM) fields. To address this need, the Girls Excelling in Mathematics and Science (GEMS) research team at Purdue started a GEMS club at Lew Wallace School in Indianapolis, referred to as Indy GEMS Club. GEMS research assistants Maria Eloisa Nuguid, Yi Zhu, and Grace Gochnauer worked with Professor Elizabeth Suazo-Flores. This article is a description of the first Indy GEMS Club experience that consisted of hands-on activities created by GEMS founder Laura Reasoner Jones. The activities were hidden Legos, cup stacking, building a zipline, creating a water filter, and making a coin battery. Once a week for four weeks, the Purdue GEMS team met with a group of 12 to 18 energetic third and fourth grade girls ready to engage in these informal STEM activities together. The girls communicated, collaborated, and most importantly had fun doing STEM in an environment that is different from a traditional classroom setting. There was an opportunity to engage the girls in an outdoor setting for the water filter activity. We were invited for a second semester at Lew Wallace School for Spring of 2023. For upcoming Indy GEMS Club, we are developing visuospatial research-based activities that involve analyzing space with imagery through drawing, creating, building, and inquiry. We argue that Indy GEMS Club will continue to benefit the community and students by providing them with opportunities to collaborate and engage in rich, hands-on, and interactive activities that portray them as doers of science and mathematics