Mechanics Course Research Articles

DIY-PIV system for Poiseuille flow investigation in undergraduate fluid mechanics course

Fluid flow visualization techniques are becoming more widespread every year due to the availability of lasers, high-speed cameras, and the development of a large amount of image processing software. Nowadays, one of the most popular methods of flow optical visualization is particle image velocimetry (PIV). PIV is an innovative way to measure and analyze fluid characteristics, giving students a more in-depth understanding of how fluids move. This paper is focused on using low-cost components and free software to implement PIV for Poiseuille flow investigation in an undergraduate fluid mechanics course. The introduction discusses how PIV is being used as a complementary method in educational institutions, highlights the high cost of equipment to implement PIV, and gives examples of low-cost do-it-yourself (DIY)-PIV systems. The following sections present the theoretical background, descriptions of the DIY-PIV experimental setup, and plan of the investigation for the Poiseuille flow analysis. A brief overview of free image processing software for the PIV implementation is also provided. The last section presents the results of the Poiseuille flow study and analyzes the measurement quality using the created DIY-PIV system. The present experimental investigation covers topics and reinforces skills related to concepts: laminar flow, Poiseuille flow (velocity distribution, maximum and average velocity), Reynolds number, and measurement error.

Cables of a prescribed length under concentrated or distributed loads

A general analysis of inextensible perfectly flexible cables of negligible weight and a prescribed length, loaded by an arbitrary number of concentrated loads, or by a uniformly distributed load per unit horizontal length, is presented. A catenary cable under its own weight, with or without a concentrated force, is also considered. The sags under loads and tensions in all segments of the cable are determined. The results are derived in closed-form, apart from a numerical solution of a single nonlinear algebraic equation for a suitably introduced parameter in the last step of the analysis. The study complements the treatment of cables under concentrated forces available in undergraduate textbooks, which omit the consideration of cables whose length is prescribed in advance. The general analysis may be found appealing for a senior or graduate structural mechanics course, while its specialization to cables with two or three loads only is well suited for an introductory mechanics course. Expressions for a catenary cable subjected to a concentrated load at its midpoint are also derived, with only one nonlinear transcendental equation for the introduced load parameter needing to be solved numerically. Three student projects are suggested which address the existence and uniqueness of the cable configuration under a concentrated force with a specified sag and length of the cable, the lifting of two symmetrically hung loads by an upward force, and the determination of the deformed shape and tension in a catenary cable subjected to a concentrated force at an arbitrary point of the cable.

Undergraduate students’ models of single- and multi-electron atoms

ABSTRACT Quantum physics forms the basis for exciting new technologies, including quantum computers, quantum encryption, and quantum entanglement. The advancement of science and technology highlights the importance of mastering quantum physics and its applications, not only at the college level but also as early as high school. In this multiple case study, we investigated first- and second-year undergraduate college students’ models of single and multi-electron atoms after completing a modern mechanics course, which addressed basic QM topics. The students’ models were categorised into four primary categories: the discrete entity (particle) model, hybrid model, quantum-like model, and quantum model, and subcategories for atom structure and electron attribution and motion. Despite being introduced to quantum concepts in high school and first-year undergraduate calculus-based physics classes, many students constructed incomplete, inaccurate, or incoherent models. Seven of eight students’ atomic structure models and six of eight students’ electron attribution and motion models were classified as discrete entity and hybrid models. The findings of this study reveal students’ conceptual challenges in explaining the structure of single and multiple-electron atoms and shed light on the factors contributing to the persistent difficulties in their understanding of atomic structure in the realm of quantum mechanics.

Examining Student Perceptions of Engagement and Learning in a Flipped Introductory Agricultural Mechanics Course

Active, student-centered approaches to teaching and learning in university classrooms have been given greater focus in recent years. Consequently, the use of flipped classrooms in American universities has proliferated considerably. Evidence suggests that flipped classrooms have been successfully employed in agricultural coursework, such as university-level agricultural mechanics courses. Theoretically underpinned by Murillo-Zamorano et al.’s (2019) Flipped Classroom in Higher Education model, the purpose of our study was to determine students’ perceptions of their engagement and learning in a flipped introductory-level agricultural mechanics course taught at Illinois State University. We used a valid and reliable electronic instrument to collect data from 61 undergraduate students over the course of four semesters. Our findings indicate that using a flipped classroom design to deliver an introductory-level agricultural mechanics course is a worthy endeavor that can positively impact students’ course experience. We are seeing similar results each semester, which suggest that our students prefer this teaching style over a traditional lecture style. The lead author intends to continue teaching the AGR 130: Introduction to Agricultural Engineering Technology course with a flipped classroom design for the foreseeable future. Our recommendations include: (1) instructors of introductory-level agricultural mechanics courses consider using a flipped classroom approach and (2) replicating our study to further examine this topic.

Smartphone-based undergraduate research projects in an introductory mechanics course

At the University of Göttingen, we implemented undergraduate research projects into a first-year mechanics course for physics majors and teacher-training students. Our primary goal was to foster students’ affective factors and higher-order thinking skills in a self-directed, crosslinking, inquiry-based learning setting. A total of 160 students were organized into 40 small groups which worked on one of six open-ended experimental tasks, utilizing smartphone sensors for flexible first-hand data collection outside laboratories. The tasks originate from the Erasmus+ project DigiPhysLab and were significantly modified and opened to be used for undergraduate research projects. In this manuscript, we present the underlying rationales behind this program, outline the core concepts behind the developed experimental tasks, and explain the actual implementation. Additionally, we offer insights into the assessment process for the project work, including the evaluation of scientific posters and responses to eight reflection questions. To facilitate this, we have employed two rubrics to ensure a comprehensive evaluation process.

A Unified Method for Determining the Sign Convention of Bending Moments in Mechanics Courses

A Unified Method for Determining the Sign Convention of Bending Moments in Mechanics Courses

Research on Mechanics Course Teaching Reform in Local Universities Centered on Students

Research on Mechanics Course Teaching Reform in Local Universities Centered on Students

Construction and Practice of the Case Base of Theoretical Mechanics Course in Military Colleges Based on Sports Events

Construction and Practice of the Case Base of Theoretical Mechanics Course in Military Colleges Based on Sports Events

Teaching Tips: Employing Critical Reflection in a Fluid Mechanics Course to Improve and Document Ethics Learning by Undergraduate Engineering Students

Teaching Tips: Employing Critical Reflection in a Fluid Mechanics Course to Improve and Document Ethics Learning by Undergraduate Engineering Students

Performance of Students in Solid Mechanics Course and the Role of Fundamental Courses for Engineering Diploma Programme

This study investigates student performance in Solid Mechanics in a Civil Engineering diploma program in Malaysia that uses Outcome-Based Education (OBE). The study evaluates the association between fundamental course performance and success in Solid Mechanics, using data from 72 students. The study takes a mixed-methods approach that includes grade distribution analysis and assessment component evaluation. Tests and assignments each contribute for 20% of the total score and the final exam accounting for 60% of the total score of Solid Mechanics. Students scored an average of 50.4% on the test evaluation, 81.8% on the assignment and 51.9% on the final exam. The results show an 80.6% of total 72 students pass in Solid Mechanics, with a bell-shaped grade distribution that is somewhat negative. The majority of students received grades in the B to C range, demonstrating adequate course calibration. Individual assessment components had variable success percentages, with 91.7% for assignments, 55.6% for test, and 59.7% for the final exam. Furthermore, the study discovered a connection between performance in foundational courses such as Calculus and Physics with the success in Solid Mechanics. Students with poor Calculus skills were more likely to fail Solid Mechanics, even when they performed quite well in Physics. This finding emphasizes the importance of fundamental courses in understanding and comprehending Solid Mechanics concepts. The study’s findings include the need for focused interventions to assist struggling students and the establishment of early intervention programs. These findings contribute to the increasing body of research on engineering education in Malaysia, providing valuable insights for curriculum design and teaching practices in OBE-based engineering programs.

The Application of Digital Technology in Online and Offline Blended Teaching of Mechanical Principles Course

The Application of Digital Technology in Online and Offline Blended Teaching of Mechanical Principles Course

Teaching Reform of Mechanical Productive Practice Course for Outstanding Engineers Training

Teaching Reform of Mechanical Productive Practice Course for Outstanding Engineers Training

Application of Robot Dynamic Tracking Predictive Control in Mechanical Control Engineering Course

Application of Robot Dynamic Tracking Predictive Control in Mechanical Control Engineering Course

Exploration and Practice of Teaching Reform in Mechanical Principles Course Guided by the Cultivation of Students' Application Ability

Exploration and Practice of Teaching Reform in Mechanical Principles Course Guided by the Cultivation of Students' Application Ability

Teaching Reform and Exploration of Mechanical Drawing Course Based on OBE Teaching Concept

Teaching Reform and Exploration of Mechanical Drawing Course Based on OBE Teaching Concept

Research on the Integration of Ideological and Political Elements into Mechanical Drawing Courses

Research on the Integration of Ideological and Political Elements into Mechanical Drawing Courses

Improvised Freon Extractor as an Innovative Trainer

The decade of the 1990's has been a challenging time for the Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC&R) industry worldwide. Due to its vital role in the destruction of the stratospheric ozone layer, provisions of the Montreal Protocol and its various amendments required the complete phase-out of chlorine-containing refrigerant such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Appliances such as window type air-conditioners, motor vehicle air-conditioners, and refrigerators, rely on ozone depleting refrigerants and their substitutes. In this case, the regulation of the Environmental Protection Agency (EPA) which prohibits the venting of refrigerants compounds to the atmosphere must be followed. Along this line of concern, educational institutions need to be aware of this technological gap specifically in developing programs in Heating, Ventilation, Air-conditioning and Refrigeration for environmental protection against incorrect disposal of refrigerant. The aim of this study was to develop an Improvised Freon Extractor as an Innovative Trainer to help students and instructors in the Bachelor of Industrial Technology and
 Bachelor of Science in Mechanical Engineering courses in their effective teaching-learning of lessons in Refrigeration and Air-conditioning subjects. The results of the study revealed that the developed innovative trainer contains the following parts: electrical parts - includes the dual capacitor, banana plug, compressor, fan motor, air swing motor, air swing motor switch, thermostat switch, and selector switch; nonelectrical parts - frame housing, frame cover, suction and discharge valve, caster wheels, filter receiver drier assembly and condenser. The Improvised Freon Extractor as an Innovative Trainer was also found to be suitable to serve as an alternative learning material that assists the learning of Refrigeration and Air-conditioning subjects in the Bachelor of Industrial Technology and Bachelor of Science in Mechanical Engineering courses

Research on Design Theory Teaching in Basic Mechanical Design Courses in Colleges and Universities

Research on Design Theory Teaching in Basic Mechanical Design Courses in Colleges and Universities

Socioeconomic status moderates neural markers of cognitive reappraisal across preschool

Emotion regulation (ER) is critical for children’s healthy socio-emotional development, in part through its modulation of negative emotions that might otherwise place children at risk for psychopathology. The cognitive ER strategy of reappraisal appears to be particularly protective against the development of symptoms of anxiety and depression during childhood. Despite widespread acceptance of the benefits of reappraisal for children’s long-term affective function, little is known about the developmental mechanisms that support emerging reappraisal in young children. Proximal mechanisms supporting reappraisal include biological processes; the modulation of reactivity to negative emotional stimuli is visible at the neural level through the Late Positive Potential (LPP). Influences on the developmental course of mechanisms like the LPP almost certainly include contextual factors, including quality of the environment, which have been largely ignored in work to date. The present study included a test of early (age 3–4) socioeconomic status (SES) as a moderator of children’s reappraisal, evidenced by differences in the LPP to passive view and reappraisal conditions, at age 5. Results supported the presence of moderation. Reappraisal was visible as differences in LPP across conditions at high, but not low, levels of SES. Findings offer a foundation for delineating the development of reappraisal and understanding contexts that may promote preschoolers’ reappraisal. Results also contribute to the delineation of the role of early psychophysiological markers in affective function and early risk for psychopathology.

Predictors of Long-COVID and Chronic Impairment of Exercise Tolerance in Spiroergometry in Patients after 15 Months of COVID-19 Recovery.

The aim of the study was to identify factors that may cause the presence of long COVID and to assess factors that affect chronic limited exercise tolerance in spiroergometry after one-year follow-up in patients who had recovered from COVID-19. Of 146 patients hospitalised in the Cardiology Department, 82 completed a one-year follow-up (at least 15 months post-COVID-19 recovery). We compared their conditions at initial screening and follow-up to analyse the course of long COVID and exercise intolerance mechanisms. Clinical examinations, laboratory tests, echocardiography, cardiopulmonary exercise testing, and body composition analysis were performed. The patients, after one-year follow-up, had significantly higher levels of high-sensitivity cardiac troponin T (hs-cTnT) (p = 0.03), left atrium diameter (LA) (p = 0.03), respiratory exchange ratio (RER) (p = 0.008), and total body water content percentage (TBW%) (p < 0.0001) compared to the 3-month assessment. They also had lower forced vital capacity in litres (FVC) (p = 0.02) and percentage (FVC%) (p = 0.001). The factors independently associated with a decline in maximum oxygen uptake (VO2max) after one-year follow-up included the percentage of fat (OR 2.16, 95% CI: 0.51-0.77; p = 0.03), end-diastolic volume (EDV) (OR 2.38, 95% CI 0.53-0.78; p = 0.02), and end-systolic volume (ESV) (OR 2.3, 95% CI: 0.52-0.78; p = 0.02). Higher left ventricular volumes and fat content (%) were associated with a reduced peak VO2max when assessed 15 months after COVID-19 recovery.