Mechanics Course Research Articles

Modal finite element correlation for computer aided engineering education

AbstractThe main challenge faced by many mechanical engineering educators is the implementation of real solutions during their courses. One alternative can be a realistic case study, where the students can be engaged in the development and analysis process currently applied in the industry. This kind of teaching process not only can be used to improve the quality of teaching‐learning process but also the students can have opportunities to solve real engineering problem. Therefore, this paper reports a realistic case implemented in mechanical engineering courses given in bachelor's and master's degrees. The component under evaluation has been selected considering the student's interest, this criterion was also taken to involve several students into a real project process to their learning development. The same problem was solved during an academic semester, it was solved using different approaches and student's abilities. This procedure can be replicated for students and teachers by following steps. The first step in this process was to describe the theoretical basis for modal analysis to understand how it was structured a numerical finite element model. This model was then solved and simulated using Hypermesh, Optistruct, and HyperView software to obtain numerical modal parameters. On the other, hand, the experimental modal parameters were obtained using a three‐dimensional scanning vibrometer on 60 samples. It is well noted that the implementation of engineering software commonly used at the industry would increase students' confidence. This allows students to perform real problem‐solving activities to develop outcomes as establish goals, plan task, meet deadlines. These activities are extremely important to the actual automotive industry. Therefore, this paper shows an engineering solution process to provide a learning alternative to teach the modal finite method solutions correlation with experimental solutions.

Roles of Neuronal Protein Kinase Cε on Endoplasmic Reticulum Stress and Autophagic Formation in Diabetic Neuropathy.

In chronic diabetic neuropathy (DN), the cellular mechanisms of neuropathic pain remain unclear. Protein kinase C epsilon (PKCε) is an intracellular signaling molecule that mediates chronic pain. This paper addresses the long-term upregulated PKCε in DN associated with endoplasmic reticulum (ER) stress and autophagic formation and correlates to chronic neuropathic pain. We found that thermal hyperalgesia and mechanical allodynia course development were associated with PKCε upregulation after DN but not skin denervation. Pathologically, PKCε upregulation was associated with the expression of inositol-requiring enzyme 1α (IRE1α; ER stress-related molecule) and ubiquitin D (UBD), which are involved in the ubiquitin-proteasome system (UPS)-mediated degradation of misfolded proteins under ER stress. Manders coefficient analyses revealed an approximately 50% colocalized ratio for IRE1α(+):PKCε(+) neurons (0.34-0.48 for M1 and 0.40-0.58 for M2 Manders coefficients). The colocalized coefficients of UBD/PKCε increased (M1: 0.33 ± 0.03 vs. 0.77 ± 0.04, p < 0.001; M2: 0.29 ± 0.05 vs. 0.78 ± 0.04; p < 0.001) in the acute DN stage. In addition, the regulatory subunit p85 of phosphoinositide 3-kinase, which is involved in regulating insulin signaling, exhibited similar expression patterns to those of IRE1α and UBD; for example, it had highly colocalized ratios to PKCε. The ultrastructural examination further confirmed that autophagic formation was associated with PKCε upregulation. Furthermore, PKCεv1-2, a PKCε specific inhibitor, reverses neuropathic pain, ER stress, and autophagic formation in DN. This finding suggests PKCε plays an upstream molecule in DN-associated neuropathic pain and neuropathology and could provide a potential therapeutic target.

Cardiorespiratory dynamics during respiratory maneuver in athletes.

Introduction: The modern practice of sports medicine and medical rehabilitation requires the search for subtle criteria for the development of conditions and recovery of the body after diseases, which would have a prognostic value for the prevention of negative effects of training and rehabilitation tools, and also testify to the development and course of mechanisms for counteracting pathogenetic processes in the body. The purpose of this study was to determine the informative directions of the cardiorespiratory system parameters dynamics during the performing a maneuver with a change in breathing rate, which may indicate the body functional state violation. Methods: The results of the study of 183 healthy men aged 21.2 ± 2.3 years who regularly engaged in various sports were analyzed. The procedure for studying the cardiorespiratory system included conducting combined measurements of indicators of activity of the respiratory and cardiovascular systems in a sitting position using a spiroarteriocardiograph device. The duration of the study was 6min and involved the sequential registration of three measurements with a change in breathing rate (spontaneous breathing, breathing at 0.1 Hz and 0.25Hz). Results: Performing a breathing maneuver at breathing 0.1Hz and breathing 0.25Hz in comparison with spontaneous breathing leads to multidirectional significant changes in heart rate variability indicators-TP (ms2), LF (ms2), LFHF (ms2/ms2); of blood pressure variability indicators-TPDBP (mmHg2), LFSBP (mmHg2), LFDBP (mmHg2), HFSBP (mmHg2); of volume respiration variability indicators - LFR, (L×min-1)2; HFR, (L×min-1)2; LFHFR, (L×min-1)2/(L×min-1)2; of arterial baroreflex sensitivity indicators - BRLF (ms×mmHg-1), BRHF (ms×mmHg-1). Differences in indicators of systemic hemodynamics and indicators of cardiovascular and respiratory systems synchronization were also informative. Conclusion: According to the results of the study, it is shown that during performing a breathing maneuver with a change in the rate of breathing, there are significant changes in cardiorespiratory parameters, the analysis of which the increments made it possible to determine of the changes directions dynamics, their absolute values and informative limits regarding the possible occurrence of the cardiorespiratory interactions dysregulation.

Locus of Control and Pedagogy in Skill-Based Agricultural Mechanics

Teachers of agriculture have use project-based learning as a primary teaching method in agricultural mechanics since the 19th century. These methods teach the information and motivate students to engage the content. Locus of Control (LOC) categorizes the relationship with decision-making and motivation. Internal LOC have a higher level of internal motivation and desire a central role in decision-making processes. External LOC typically do not seek out opportunities for decision making. A student with an internal LOC acts on the world and a student with an external LOC believes the world acts on them. This research was to determine if students’ LOC differentiated between hands-on compared to lecture-based teaching. Students in an agricultural mechanics course at [University] (N = 38) were neither internal nor external (f =16) LOC, those with a tendency towards one or the other were more internal (f = 15) and (f = 7) were external LOC. Most students felt slightly positive toward project-based learning (M = 3.61, SD = 0.70) and slightly negative toward lecture-based learning (M = 2.78, SD = 0.85). Either LOC plays no role in students’ feelings toward project-based methods or there are so few internal students that no correlation could be detected

Critical thinking activities in fluid mechanics – A case study for enhanced student learning and performance

We describe the implementation of Critical Thinking Activities (CTA) designed to encourage ‘critical thinking’ in an undergraduate engineering Fluid Mechanics course. Critical thinking can be a vague term both difficult to grasp and even more so to measure. Using a longitudinal case study we analyse quantitative and qualitative data collected over three years to explore the overarching question: “how do we know students have thought critically?”. We investigate and evaluate the quantitative data that emerged from students undertaking the CTA and the impact of this on their performance. The results indicate that students who performed well in the CTA achieved a final grade for the course of 5 or more (Credit, Distinction or High Distinction). Qualitative data from student feedback demonstrated that the CTA was a significant factor in reinforcing student learning, enabling us to identify areas of misconception and areas in which they could improve. While the study is situated in an engineering context at the University of Queensland, the paper is an exemplar of embedded and sustainable practice, is equally transferable to other disciplinary contexts.

Teaching and Learning Computational Mathematics with Intensive Application of the Virtual Campus

Nowadays, the field of professional development in engineering requires appropriate and relevant training for a satisfactory insertion in the labor market. This requires that educational institutions provide not only the specific knowledge of the career being studied but also must complement it with other skills necessary for adequate performance in the work environment. Based on these premises, this paper describes the design of a classroom experience to be implemented in the subject of Advanced Calculus (AC), a third-level subject of the Mechanical Engineering course. The proposed activities are developed in the Computer and Multidisciplinary Laboratory of Basic Sciences available at the faculty and seek to encourage the use of the virtual campus, where the mediation between the content of the subject and the concrete applications of simple engineering models are the axis to develop the topic: Analytical Functions of Complex Variables (AFCV).

Hybrid project-based didactic strategy in mechanical engineering courses

Adopting a didactic strategy that promotes education and autonomous work in the training of an engineering student while it generates academic products for the teacher-student binomial is a real possibility. The application of such a strategy in the hybrid educational model is presented to implement interactive courses in the Mechanical Engineering career at the Universidad Nacional Autónoma de México. The methodological foundation is highlighted as a basis for the pedagogical design of the bimodal courses, and the practical cases developed by the authors in the undergraduate and graduate programs in mechanical engineering under this modality are presented. The research provides the analysis of results obtained from seven subject programs during the last academic periods from the second semester of 2015 to the first semester of 2022. The research based on design specifications, learning objectives, temporal organization, activities, formative and summative evaluation, and a scoring guide proved the efficiency of hybrid format for mechanical engineering courses.

Challenges in addressing student difficulties with basics and change of basis for two-state quantum systems using a multiple-choice question sequence in online and in-person classes

Research-validated multiple-choice questions comprise an easy-to-implement instructional tool for scaffolding student learning and providing formative assessment of students’ knowledge. We present findings from the implementation of a research-validated multiple-choice question sequence on the basics of two-state quantum systems, including inner products, outer products, translation between Dirac notation and matrix representation in a particular basis, and change of basis. This study was conducted in an advanced undergraduate quantum mechanics course, in both online and in-person learning environments, across three years. For each cohort, students had their learning assessed after traditional lecture-based instruction in relevant concepts before engaging with the multiple-choice question sequence. Their performance was evaluated again afterward with a similar assessment and compared to their earlier performance. We analyze, compare, and discuss the trends observed in the three implementations.

Impact of 3D-printed laboratory equipment in vibrations and controls courses on student engineering identity, motivation, and mindset

This paper describes the implementation of innovative 3D-printed laboratory equipment linked to inquiry-based learning activities designed to improve learning, increase engineering identity and motivation, and foster a growth mindset in students taking undergraduate level mechanical vibrations courses, control theory courses, and associated laboratories. These innovative designs create new opportunities for hands-on learning, are low-cost, portable, and can be adapted for use in multiple science and engineering disciplines. The learning activities are based on the POGIL model, which has been used across a variety of disciplines including engineering. We describe the features of three separate devices (spring-connected sliding carts, compliant parallel arms with fixed-free ends and a slider mass, and a pendulum with variable tip load) implemented using a quasi-experimental approach with 510 duplicated students across three semesters during the COVID-19 pandemic in multiple lecture courses and laboratory sections. We also present an assessment of impact based on descriptive statistical analyses of survey data for student-reported learning gains and pre-post paired comparison tests on validated instruments measuring perceptions of engineering identity, engineering motivation, and growth mindset. Further, we conducted a student focus group and include salient instructor observations. Results show most students participating in the learning activities using these devices report that it supported their learning “a lot” or “a great deal.” In addition, on six of seven surveyed learning outcomes, most students reported feeling confident enough to complete them on their own or even teach them to someone else. Our data did not show a measurable impact on engineering identity, engineering motivation, or growth mindset, though it does suggest further investigation is merited.

Ingenious Game: Insights Into Evolving From a Learning Card Game to a Learning Software Application Game

Ingenious is a collaborative and competitive learning game application in which groups of students compete against each other in a product design and development (PDD) scenario where each group is responsible for a multidisciplinary team of engineers. The game has been used since 2020 to support a mechanical engineering master course. In this period, the game evolved from a card game to a software application. During the four game rounds representing the PDD phases, the players learn when to use over 80 different engineering design techniques. By choosing varying engineers and techniques, a student group creates a design strategy with a cost to execute and might be proven more effective than the competitors’ strategies. Winning the game is about effectiveness in solving the challenges posed in the PDD scenario at a minimum cost. Once the game allows scenario customisation, new PDD scenarios can be created with different complexity levels. In the gamified classroom, grading is not a result of winning the game but a reflection of the group’s choices and consequences while playing the game. This article presents the different game versions, describes the Ingenious game mechanics and dynamics and reflects on the game evolution and coverage of the Octalysis dimensions.

Potential and Feshbach s-wave resonances in coupled atomic collision channels

We discuss s-wave scattering in an atomic binary collision with two coupled channels, tunable by an external magnetic field, one channel open and the other closed for the incident energies considered. The analysis is performed with a stylized model of square-well potentials. This simplification allows for a pedagogically thorough discussion of the different scattering resonances that appear in coupled channels. One of them, the potential resonances at vanishing energy, occurs as a bound state of the coupled system emerges, in turn, tuned at a very precise value of the external field. The other resonances, described by Feshbach theory, occur when the incident energy is near a bound state of the closed channel, as if it were decoupled from the open channel. These resonances exist for values of the external field above a particular threshold value. Besides the potential intrinsic value of this study in a quantum mechanics course, as the analysis can be performed with minor numerical calculations, it is also an aid for the understanding of current research advances in the exciting field of ultracold gases.

Causal inference: relating language to event representations and events in the world.

Events are not isolated but rather linked to one another in various dimensions. In language processing, various sources of information-including real-world knowledge, (representations of) current linguistic input and non-linguistic visual context-help establish causal connections between events. In this review, we discuss causal inference in relation to events and event knowledge as one aspect of world knowledge, and their representations in language comprehension. To evaluate the mechanism and time course of causal inference, we gather insights from studies on (1) implicit causality/consequentiality as a specific form of causal inference regarding the protagonists of cause/consequence events, and (2) the processing of causal relations. We highlight the importance of methodology in measuring causal inference, compare the results from different research methods, and emphasize the contribution of the visual-world paradigm to achieve a better understanding of causal inference. We recommend that further investigations of causal inference consider temporally sensitive measures and more detailed contexts.

Standardized approach for extubation during extracorporeal membrane oxygenation in severe acute respiratory distress syndrome: a prospective observational study

BackgroundExtubation during extracorporeal oxygenation (ECMO) in severe acute respiratory distress syndrome (ARDS) has not been well studied. Despite the potential benefits of this strategy, weaning from ECMO before liberation from invasive mechanical ventilation remains the most frequent approach. Our aim was to evaluate the safety and feasibility of a standardized approach for extubation during ECMO in patients with severe ARDS.ResultsWe conducted a prospective observational study to assess the safety and feasibility of a standardized approach for extubation during ECMO in severe ARDS among 254 adult patients across 4 intensive care units (ICU) from 2 tertiary ECMO centers over 6 years. This consisted of a daily assessment of clinical and gas exchange criteria based on an Extracorporeal Life Support Organization guideline, with extubation during ECMO after validation by a dedicated intensive care medicine specialist. Fifty-four (21%) patients were extubated during ECMO, 167 (66%) did not reach the clinical criteria, and in 33 (13%) patients, gas exchange precluded extubation during ECMO. At ECMO initiation, there were fewer extrapulmonary organ dysfunctions (lower SOFA score [OR, 0.88; 95% CI, 0.79–0.98; P = .02] with similar PaO2/FiO2) when compared with patients not extubated during ECMO. Extubation during ECMO associated with shorter duration of invasive mechanical ventilation (7 (4–18) vs. 32 (18–54) days; P < .01) and of ECMO (12 (7–25) vs. 19 (10–41) days; P = .01). This was accompanied by a lower incidence of hemorrhagic shock (2 vs. 11%; P = .05), but more cannula-associated deep vein thrombosis (49 vs. 31%; P = .02) and failed extubation (20 vs. 6%; P < .01). There were no increased major adverse events. Extubation during ECMO is associated with a lower risk of all-cause death, independently of measured confounding (adjusted logistic regression OR 0.23; 95% confidence interval 0.08–0.69, P = .008).ConclusionsA standardized approach was safe and feasible allowing extubation during ECMO in 21% of patients with severe ARDS, selecting patients who will have a shorter duration of invasive mechanical ventilation, ECMO course, and ICU stay, as well as fewer infectious complications, and high hospital survival.

Evaluation of teaching method for fluid mechanics course in engineering education

The professional technology training of student is the important objective of engineering education, which could present the specialized ability in the future. This task is conducted to evaluation of teaching methods for fluid mechanics course in the mechanical engineering. With the teaching practice, the advantage of teaching method is found, and the teaching quality can be revealed by the scores of integrated test. The improvement of teaching quality is contribute the development of social. According to the self-assessment, the effects of teaching method on the professional course is revealed.•The diversified teaching method is advantage to the understanding of theory and knowledge of application.•The practical training is suitable to develop the inner potential and innovation of different students.•The method allows the investigation of teaching method evaluation for the other courses with practicality.

Some remarks on projectile motion with a linear resistance force

In this article, we revisit projectile motion assuming a retarding force proportional to the velocity, . We obtain an analytical expression for the set of maxima of the trajectories, in Cartesian coordinates, without using the Lambert W function. Also, we investigate the effect of parameter k on the radial distance of the projectile showing that the radial distance oscillates from a certain critical launch angle and find an approximate expression for it. In our analysis, we consider the impact of parameter k in the kinetic energy, the potential energy, the total energy, the rate of energy loss, and the phase space. Our results can be included in an intermediate-level classical mechanics course.

Circulation of Respiratory Viruses in the City: Towards an Agent-Based Ecosystem model.

Mathematical models play an important role in management of outbreaks of acute respiratory infections (ARI). While such models are generally used to study the spread of a solitary virus, in reality multiple viruses co-circulate in the population. These viruses have been studied in detail, including the course of infection and immune defense mechanisms. We developed an agent-based model, called ABM-ARI, assimilating heterogeneous data and theoretical knowledge into a biologically motivated system, that allows to reproduce the seasonal patterns of ARI incidence and simulate interventions. ABM-ARI uses city-specific data to create a synthetic population and to construct realistic contact networks in different activity settings. Characteristics of infection, immune protection and non-specific resistance were varied between individuals to account for the population heterogeneity. For the calibration, we minimised the normalised mean absolute error between simulated and observed epidemic curves. ABM-ARI was built based on the quantitative assessment of features of predominant respiratory viruses and epidemiological characteristics of the population. It provides a good fit to the observed epidemic curves for different age groups and viruses. We also simulated one-week school closures when student absences were at or above 10%, 20% or 30% and found that only 10% and 20% thresholds resulted in a reduction of the incidence. ABM-ARI has a great potential in tackling the challenge of emerging infections by simulating and evaluating the effectiveness of various interventions.

Penerapan Media Pembelajaran Android Pada Mata Kuliah Elemen Mesin: Analisis Kebutuhan dan Kesiapan

Learning media is important in supporting an effective and interactive learning process. In the current digital era, the use of Android-based technology as a learning tool has become a major concern in improving the quality of education. This article discusses the application of Android-based learning media in the Mechanical Elements course. This research investigates the readiness and need for using Android-based Aqidah learning media. This study used a survey method with semester II student subjects from the Automotive Technology Vocational Education Study Program at Lancang Kuning University. Data was collected by filling out a questionnaire, and the results were analyzed descriptively. The research results show several important things. First, all students (100%) feel interested in Android-based learning media. Second, after understanding the use of Android learning media, around 87.6% of students acknowledged the need for this media in learning. Third, applying Aydin and Tasci's ELR model shows that readiness to use Android learning media is included in the Ready category. However, several factors need to be improved slightly. The average ELR value is 3.73, exceeding the threshold of 3.4, indicating readiness. However, it should be noted that the Self-Improvement aspect has a low ELR value, namely 3.24, indicating the need for improvement. Based on these findings,

Neuroplastic Changes Associated With Hybrid Exercise-Cognitive Training in Stroke Survivors With Mild Cognitive Decline: A Randomized Controlled Trial

Background Exercise and cognitive training have been shown to induce neuroplastic changes and modulate cognitive function following stroke. However, it remains unclear whether hybridized exercise-cognitive training facilitates cortical activity and further influences cognitive function after stroke. Objective The study aimed to investigate the effects of 2 hybridized exercise-cognitive trainings on neuroplastic changes and behavioral outcomes in stroke survivors with mild cognitive decline. Methods This study was a single-blind randomized controlled trial. Stroke survivors were randomly assigned to 1 of 3 groups: (1) sequential exercise-cognitive training (SEQ), (2) dual-task exercise-cognitive training (DUAL), or (3) control group (CON). All groups underwent training 60 min per day, 3 days per week, for a total of 12 weeks. The primary outcome was the resting-state (RS) functional connectivity (FC) in functional magnetic resonance imaging. Secondary behavioral outcomes included cognitive and physical functions. Results After 12 weeks of training, patients in the SEQ group (n = 21) exhibited increased RS FC between the left occipital lobe and posterior cingulate gyrus with right parietal lobe, compared to the DUAL (n = 22) and CON (n = 20) groups. Additionally, patients in the DUAL group showed increased FC of the left temporal lobe. However, changes in behavioral outcome measures were non-significant among the 3 groups (all P’s > .05). Conclusions This study highlights the distinct neuroplastic mechanisms associated with 2 types of exercise-cognitive hybridized trainings. The pre-post functional magnetic resonance imaging measurements illustrated the time course of neural mechanisms for cognitive recovery in stroke survivors following different exercise-cognitive training approaches. Trial registration. NCT03230253.

Brain Metabolomics in Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS).

The course of pathophysiological mechanisms involved in fragile X-associated tremor/ataxia syndrome (FXTAS) remains largely unknown. Previous proteomics and metabolomics studies conducted in blood samples collected from FMR1 premutation carriers with FXTAS reported abnormalities in energy metabolism, and precursors of gluconeogenesis showed significant changes in plasma expression levels in FMR1 premutation carriers who developed FXTAS. We conducted an analysis of postmortem human brain tissues from 44 donors, 25 brains with FXTAS, and 19 matched controls. We quantified the metabolite relative abundance in the inferior temporal gyrus and the cerebellum using untargeted mass spectrometry (MS)-based metabolomics. We investigated how the metabolite type and abundance relate to the number of cytosine-guanine-guanine (CGG) repeats, to markers of neurodegeneration, and to the symptoms of FXTAS. A metabolomic analysis identified 191 primary metabolites, the data were log-transformed and normalized prior to the analysis, and the relative abundance was compared between the groups. The changes in the relative abundance of a set of metabolites were region-specific with some overlapping results; 22 metabolites showed alterations in the inferior temporal gyrus, while 21 showed differences in the cerebellum. The relative abundance of cytidine was decreased in the inferior temporal gyrus, and a lower abundance was found in the cases with larger CGG expansions; oleamide was significantly decreased in the cerebellum. The abundance of 11 metabolites was influenced by changes in the CGG repeat number. A histological evaluation found an association between the presence of microhemorrhages in the inferior temporal gyrus and a lower abundance of 2,5-dihydroxypyrazine. Our study identified alterations in the metabolites involved in the oxidative-stress response and bioenergetics in the brains of individuals with FXTAS. Significant changes in the abundance of cytidine and oleamide suggest their potential as biomarkers and therapeutic targets for FXTAS.

Pleiotropic effects of extracellular vesicles from induced pluripotent stem cell–derived cardiomyocytes on ischemic cardiomyopathy: A preclinical study

Stem cell-secreted extracellular vesicles (EVs) play essential roles in intercellular communication and restore cardiac function in animal models of ischemic heart disease. However, few studies have used EVs derived from clinical-grade stem cells and their derivatives with stable quality. Moreover, there is little information on the mechanism and time course of the multifactorial effect of EV therapy from the acute to the chronic phase, the affected cells, and whether the effects are direct or indirect. Induced pluripotent stem cell-derived cardiomyocytes (iPSCM) were produced using a clinical-grade differentiation induction system. EVs were isolated from the conditioned medium by ultracentrifugation and characterized in silico, in vitro, and in vivo. A rat model of myocardial infarction was established by left anterior descending artery ligation and treated with iPSCM-derived EVs. iPSCM-derived EVs contained microRNAs and proteins associated with angiogenesis, antifibrosis, promotion of M2 macrophage polarization, cell proliferation, and antiapoptosis. iPSCM-derived EV treatment improved left ventricular function and reduced mortality in the rat model by improving vascularization and suppressing fibrosis and chronic inflammation in the heart. EVs were uptaken by cardiomyocytes, endothelial cells, fibroblasts, and macrophages in the cardiac tissues. The pleiotropic effects occurred due to the direct effects of microRNAs and proteins encapsulated in EVs and indirect paracrine effects on M2 macrophages. Clinical-grade iPSCM-derived EVs improve cardiac function by regulating various genes and pathways in various cell types and may have clinical potential for treating ischemic heart disease.