Hasil untuk "Descriptive and experimental mechanics"

Erhan Huang, Ying Chang, Yangzhao Liu et al.

Heliostats constitute essential elements within concentrating solar power (CSP), where their structure, load profiles, and operational environment render wind loads a critical factor in their design considerations, as these loads directly impact the cost of energy generation. The aerodynamics significantly influence wind-induced effects, resulting in considerable variability in wind loads among different heliostat geometries. This study utilizes the Computational Fluid Dynamics (CFD) methodology to systematically examine the aerodynamic behavior of an isolated pentagonal heliostat. Employing the Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations with an atmospheric boundary layer inlet condition, the investigation focuses on the flow field and wind load characteristics at four representative pitch angles: 0° (stow position), 30°, 60°, and 90°. Findings indicate that the pitch angle exerts a decisive impact on flow separation patterns. Specifically, as the elevation angle decreases, the flow regime shifts from being predominantly influenced by the mirror surface to being governed by the support structure, mediated through an interactive coupling between these components. At the 60° operational pitch angle, the pentagonal heliostat’s distinctive corner geometry induces an asymmetric vortex configuration—characterized by a smaller vortex at the top and a larger one at the bottom—thereby disrupting the conventional vortex distribution observed in symmetric heliostat designs. A further analysis of wind load characteristics indicates that, compared to a quadrilateral heliostat, the pentagonal mirror exhibits a significantly lower Elevation Moment Coefficient, despite a slight increase in the normal force coefficient. This reduction is attributed to a balancing mechanism: the “vortex structure asymmetry” creates an upper-large–lower-small distribution of absolute negative pressure on the support surface, while the “stagnation point position” shift with elevation angle produces an upper-small–lower-large distribution of absolute positive pressure on the reflector. The interaction between these opposing trends minimizes the net pressure differential across the mirror height, thereby contributing to superior overall aerodynamic performance. The reduction in the elevation moment coefficient contributes to enhanced structural wind resistance, thereby improving the overall energy efficiency and economic viability of concentrating solar power.

Nikolaos Lampropoulos, Alexandros Vouros, Ioannis Templalexis et al.

A study on aerodynamic design studies of a blended wing–body (BWB) unmanned aerial vehicle (UAV) operating at low Mach numbers is presented. First, a parametric investigation based on analytical equations is carried out to identify the range of the necessary wetted area for the UAV to maximize endurance at a Mach number close to 0.1. A base-of-reference configuration is designed, and its aerodynamic performance is evaluated by utilizing a panel method in Xflr5. An optimization algorithm is then incorporated to trim the UAV and produce the ‘clean’ configuration. Computational fluid dynamics (CFD) simulations are performed within the OpenFoam environment to produce first the updated drag polars, and then, to analyze the integration of the nacelle and the pair of electric ducted fans (EDFs) used for the propulsion system. In particular, when examining the integration of the nacelle with a spinning electric ducted fan (EDF) standing as the propulsion system of the vehicle, a rotating, sliding mesh computational approach is adopted. Results indicate that the clean configuration is characterized by strong longitudinal stability so that the UAV has the potential to fly trimmed at very low speeds. Mounting EDFs on the back of the fuselage is conducive to higher loading with minimal drag penalty. An increased lift-to-drag ratio is achieved. Reduced wake mixing due to the EDF’s jet flow is observed. The spanwise flow that is conducive to pitch brake and loss of stability is also weak, as the suction produced by the EDF diverts the flow inboard.

Margaret Hawton

We second quantize the Fermi Lagrangian in the Lorenz gauge to obtain a covariant theory of photon quantum mechanics. Number density is real so it is interpreted as position probability density. The Hilbert space is the vector space of fields with norm 1 describing physical photons and the Poincare operators are extended to include position to represent observables. A photon continuity equation is derived that describes creation, propagation and annihilation of photons in an optical circuit. The relationship to orthodox quantum mechanics is discussed.

Tao Wang, Yu Shi

We investigate the adiabatic elimination of fast variables in relativistic stochastic mechanics, which is analyzed by using the equation of motion and the distribution function, with relativistic corrections explicitly derived. A new dimensionless parameter is introduced to characterize the timescale. The adiabatic elimination is compared with the path integral coarse graining, which is more general yet computationally demanding.

Debadrita Ghosh, Urbasi Sinha

Physicist and Nobel Laureate Richard P. Feynman once remarked ``We choose to examine a phenomenon which is impossible, absolutely impossible, to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery. We cannot make the mystery go away by ``explaining'' how it works. We will just tell you how it works. In telling you how it works, we will have told you about the basic peculiarities of all quantum mechanics'' [Feynman RP, Leighton RB, Sands M (1963 and 1965)]. The phenomenon of interference is ubiquitous in the quantum world and indeed holds within itself the explanation for many counterintuitive quantum phenomena. In this review, we choose to focus on a few ramifications and manifestations of quantum interference that have deep implications for the foundations of quantum mechanics. These include single-photon or second-order interference, two-photon or fourth-order interference and higher-order interference.

Christine Ann Florese

Gamification served as a pivotal educational strategy by incorporating game mechanics into conventional learning environments, particularly within the framework of Digital Game-Based Learning (DGBL). This study aimed to explore the effectiveness of DGBL in addressing academic challenges faced by students, with a focus on enhancing learning outcomes, engagement, motivation, and autonomy. By situating gamification within the context of Araling Panlipunan, a subject often perceived as content-heavy and challenging, the research sought to determine how game-based approaches could support more meaningful and motivating learning experiences. The study employed a descriptive quasi-experimental design, specifically utilizing a one-group pre-test and post-test model, to assess the impact of DGBL on Grade 8 students at Parañaque National High School – Baclaran. A total of forty (40) students were purposively selected from a population of 428 Grade 8 learners. A teacher-made achievement test was used to gauge baseline knowledge and learning progress, while a structured survey questionnaire measured student motivation, engagement, and perceived autonomy before and after the DGBL intervention. Findings revealed a significant improvement in students' academic performance following the implementation of gamified instruction. Additionally, there was notable growth in learners' engagement levels, intrinsic motivation, and autonomy in navigating the subject matter. The data suggested that DGBL fostered a more interactive and student-centered learning environment, helping students overcome previous difficulties with content retention and comprehension. As a result of these findings, the study proposed the GAME-UP model—a structured framework for the integration of Digital Game-Based Learning in classroom instruction. The model emphasizes the strategic use of game mechanics to enhance student motivation, promote active participation, and improve academic achievement. Overall, the research affirmed the educational potential of gamification, highlighting its value as an innovative tool for improving student learning experiences and outcomes in the 21st-century classroom.

Meilisa Cahya Pratiwi, Santi Farmasari, Ni Wayan Mira Susanti et al.

This research investigates the effectiveness of the Mind Mapping technique in improving the English writing skills of tenth-grade students at SMKN 1 Pujut. This study used a quantitative approach with a quasi-experimental design, involving two groups: an experimental class (X AP 1, 30 students) taught with Mind Mapping and a control class (X AP 3, 30 students) taught with conventional methods. Data were collected through pre-tests and post-tests of descriptive writing, and then scored based on content, organization, vocabulary, language use, and mechanics, and analyzed using SPSS with normality tests, homogeneity tests, and an Independent Samples t-test. The scores of the experimental group increased by 36.87 to 87.27 and the scores of the control group increased by 41.3 to 81.30 and statistical data confirmed that there was a significant difference (t = -5.207, p < 0.001). These findings showed that Mind Mapping was effective in terms of improving students in terms of organizing ideas, vocabulary and the quality of writing as a whole. One can conclude that Mind Mapping is a helpful teaching tool that encourages the development of creativity, logical thinking, and writing confidence, which makes it very helpful to both the teacher and the learner. Future studies could explore the long-term retention of writing skills acquired through Mind Mapping and investigate its effectiveness across different genres of writing and diverse learner populations.

Dewi Sartikawati, Abdul Wahab, Ria Hendriani

This research examines the effectiveness of English short story creation as a method to enhance students’ writing skills. Conducted at MA Al-Ma’arif Bonder with a sample of 16 tenth-grade students, the research employed a pre-experimental one-group pre-test and post-test design. Writing skills were assessed based on five aspects: ideas/content, structure, vocabulary, grammar, and mechanics. Data were analyzed using descriptive statistics and a paired sample t-test with SPSS 25. Results revealed significant improvement in students’ writing performance, with the mean score increasing from 56.8 in the pre-test to 75.3 in the post-test. The paired sample t-test produced a significance value of 0.000, indicating a positive effect of short story writing on students’ writing proficiency. This suggests that integrating creative writing activities into English instruction can foster students’ language development, motivation, and creativity.

Marguerite Alofa P. O’Brien-Melford

This study investigated the effectiveness of ChatGPT as an instructional support tool in enhancing the explanation letter writing skills of Technical Writing students at Cebu Doctors’ University. It aimed to address students’ recurring difficulties in applying the correct format, organization, elaboration, tone, and grammar, language usage, and mechanics in formal written communication. Employing a quasi-experimental pre-test/post-test design supported by a perception survey, the research examined measurable improvements in students’ performance following a ChatGPT-assisted intervention that incorporated guided modeling, interactive feedback, and revision-based activities. Fifty (50) first-year students from the EXCEL-Med Program participated in the study. Data were analyzed using descriptive statistics and a paired sample t-test. Findings revealed statistically significant improvements across all five writing elements, with the largest effect observed in format, organization, elaboration, and tone, and a moderate improvement in grammar, language usage, and mechanics. Students’ perception ratings further indicated strong agreement that ChatGPT was easy to use, enhanced confidence and understanding, and effectively supported skill development. Overall, the study concludes that ChatGPT-assisted instruction significantly improves students’ explanation letter writing performance and fosters confidence and awareness in responsible AI use. The results emphasize the potential of integrating AI-based tools as complementary pedagogical aids that support the United Nations Sustainable Development Goal 4 (Quality Education) by promoting digital literacy, communication competence, and ethical technology use in higher education.

Nurul Anjarwati, Suvi Akhiriyah

This study aimed to investigate the effectiveness of using social media videos (YouTube, Instagram, and TikTok) in improving students' writing performance in procedure texts. Utilizing a quantitative quasi-experimental design, the research involved two groups of ninth-grade beginner-level EFL students at a junior high school in Surabaya: an experimental group taught with social media videos and a control group taught through conventional methods. Data was collected through pre-tests and post-tests, and analyzed using descriptive statistics, t-tests, and effect size calculations. The independent t-test results indicated a significant difference between the experimental group and control group in writing performance (p = 0.000) with a modest effect (0.448). The experimental group experienced notable improvements across key aspects of writing, with gains of 5.77 points in content, 4.67 in organization, 4.27 in grammar, 1.20 in style, and 0.33 in mechanics from pre-test to post-test. The findings support the integration of social media videos as engaging instructional tools that enhance students’ understanding of procedure texts and foster better writing outcomes. The study concludes that social media videos can serve as effective media for developing students’ writing skills in the EFL context, making learning more relatable and dynamic.

Agung Yon, Mochamad Sidqon, Anton Breva Yunanda et al.

Abstract. This study evaluates the effectiveness of a robotics learning approach starting with practical electronics, analog robot design, and basic mechanics in enhancing elementary school students' interest in learning. The research also explores how students’ economic backgrounds influence their enthusiasm for robotics education. The subjects were 25 fifth-grade students from SDN Margorejo 1 Surabaya, selected based on specific criteria, including middle-income family backgrounds. The quasi-experimental research design included pre-test and post-test stages. Activities comprised four phases: introduction to practical electronics, simple analog robot design, basic robotics mechanics training, and robot integration and testing. Data were collected through questionnaires, observations, interviews, and project assessments. Descriptive analysis and non-parametric statistical tests measured changes in students’ interest, while qualitative methods examined economic factors affecting enthusiasm. Results revealed a 23% average increase in students’ interest in robotics. Additionally, 88% of students successfully built simple robots demonstrating creativity and functionality. Students from middle-income families maintained high enthusiasm, showing that economic constraints did not significantly hinder participation. This integrated approach effectively fosters technological interest, aligns with STEM concepts, and prepares students for technology-driven challenges. The study contributes practically and theoretically to robotics learning models for elementary education. Keywords: Robotics, Practical Electronics, Learning Interest, Elementary School, Middle-Income Economy, STEM

Shanty Halim, Sitti Sahriana, Mastang Mastang

This study examines the effectiveness of the Collect, Organize, write strategy (hereafter referred to as COW) in improving the descriptive writing skills of Building Construction students in the Engineering department of Ujung Pandang State Polytechnic (PNUP) in teaching Technical English in vocational higher education in Indonesia. The research design used was pre-experimental with a pre-test, treatment, and post-test approach. A total of 27 students participated in the study, which focused on improving writing skills across five dimensions: content, organization, grammar, vocabulary, and mechanics. The COW strategy was applied during five instructional sessions, covering topics such as workshop equipment and heavy equipment description. Data were collected through student writing assessments that were analysed using statistical tests, including t-tests and frequency distributions. The results showed a significant improvement in students' writing ability from pre-test to post-test. The average score increased from 33.85 in the pre-test to 51.77 in the post-test, with marked improvement in all five dimensions of writing. The greatest improvement was seen in content and vocabulary skills, where 59.26% of the students achieved the "Good" or "Fair" classification after the intervention. Meanwhile, grammar skills showed a bimodal distribution, and mechanics showed uniform improvement across all participants. Assessment was conducted using a rubric that measured each writing dimension separately.

Nursultan Alzhanov, Eddie Y. K. Ng, Yong Zhao

This paper presents a novel hybrid approach that integrates computational fluid dynamics (CFD), physics-informed neural networks (PINN), and fluid–structure interaction (FSI) methods to simulate fluid flow in stenotic coronary artery trees and predict fractional flow reserve (FFR) in areas of stenosis. The primary objective is to utilize a 1D PINN model to accurately predict outlet flow conditions, effectively addressing the challenges of measuring or estimating these conditions within complex arterial networks. Validation against traditional CFD methods demonstrates strong accuracy while embedding physics-based training to ensure compliance with fundamental fluid dynamics principles. The findings indicate that the hybrid CFD PINN FSI method generates realistic outflow boundary conditions crucial for diagnosing stenosis, requiring minimal input data. By seamlessly integrating initial conditions established by the 1D PINN into FSI simulations, this approach enables precise assessments of blood flow dynamics and FFR values in stenotic regions. This innovative application of 1D PINN not only distinguishes this methodology from conventional data-driven models that rely heavily on extensive datasets but also highlights its potential to enhance our understanding of hemodynamics in pathological states. Ultimately, this research paves the way for significant advancements in non-invasive diagnostic techniques in cardiology, improving clinical decision making and patient outcomes.

Marek Żukowski, Marcin Markiewicz

In June 1925 Heisenberg arrived at Helgoland/Heligoland island to escape a fit of hay fever. He returned with a sketch of a strange theory of the micro-world, which we now call quantum mechanics. This essay attempts to present a look at this theory, which tries to return to the original insight of Heisenberg on what should be the essence of a theory of atomic realm: it must be a theory of the observable events, in which fundamentally unobservable quantities have no place. No ontological status is given to elements of the mathematical formulation of the theory. The theory is about our description of events in laboratories, probabilities of which are given by the Born rule. Following Bohr, these events involve macroscopic measuring apparatuses, and the accessible final events are classically describable. Information about the events is cloneable, as it is of a classical nature. The modern quantum theory of classicality is the decoherence theory. It treats "the pointer variable" of measuring apparatus as an open system interacting with an environment consisting of all other "zillions" of degrees of freedom of the device, and anything coupled to it. Because such environment is uncontrollable we have no possibility to reverse measurements. The quantum mechanical measurement theory based on decoherence theory is reproducing the predictions of Born rule. Notwithstanding, possibility of reversing measurements and of application of Born rule in situations other than these which lead to macroscopically observable events are features of a modification of quantum mechanics which is called by its adherents "unitary quantum mechanics". As its predictions, which go beyond quantum mechanics, are not testable - we claim that unitary quantum mechanics in an interpretation of quantum mechanics. As such it is metaphysics.

Aliyu Mustapha, R. Okwori, Abdullahi Abubakar Kutiriko et al.

Traditional teaching methods, such as lectures, have long been criticized for their lack of innovation and passive learning approach, particularly in technical disciplines like Motor Vehicle Mechanics (MVM). This study explores the impact of simulation-based instruction, using the Motor Vehicle Mechanic Computer Animation Instructional Package (MVMCAIP), compared to conventional methods in enhancing students' achievement, retention, and skill performance. Employing a quasi-experimental and descriptive multi-method design, the research was conducted across technical colleges in Niger State, involving 118 Technical College II students. Of these, 58 students were taught using MVMCAIP, while 60 received traditional instruction. Data collection tools included the Motor Vehicle Mechanic Achievement Retention Test (MVMART), the Motor Vehicle Mechanic Skill Performance Test (MVMSPT), and lesson plans. Findings reveal that simulation-based instruction significantly enhances student performance across all metrics, with gender influencing achievement scores but showing no significant interaction effect with instructional methods. These results highlight the potential of simulation tools to revolutionize technical education by providing interactive, engaging, and effective learning experiences. The study recommends integrating simulation technologies like MVMCAIP into MVM curricula and prioritizing professional development programs to enhance educators’ proficiency with these tools, paving the way for more impactful and future-ready technical education.

Mungkap Mangapul Siahaan, Setia Oktaviana Sirait, Irene Adryana Nababan

This study aims to investigate the effect of using the Think Talk Write Strategy on the writing procedure text capability of eleventh-grade students at vocational SMK GKPI 1 Pematangsiantar. This research used a quasi-experimental research design. The population of this study was the eleventh-grade students of vocational SMK GKPI 1 Pematangsiantar, and the total number of students was 216. The sample of this study was divided into two classes: the experimental class was (XI KW), consisting of 27 students who used the Think Talk Write strategy, and the control class (XI TJTL) was composed of 27 students who only used the cturing strategy. The data collection instruments used writing tests for the pre-test and post-test. Brown’s writing assessment rubric was used in this research, and it included content, organization, grammar, vocabulary, and mechanics. SPSS 26 Version was used to analyze the data by conducting descriptive analysis, normality test, Wilcoxon test, homogeneity test, and Mann-Whitney test. The data analysis using the Mann-Whitney test showed that the Assymp. Sig (2-tailed) value of 0.007< 0.05. Based on these findings, Ha is accepted, and Ho is rejected. Therefore, it can be concluded that The ink Talk Write Strategy significantly affected the writing procedure text capability of the eleventh-grade students at vocational SMK GKPI I Pematangsiantar.

P. Paganini

This text is a modern introduction to the Standard Model of particle physics for graduate students and advanced undergraduate students. Assuming only prior knowledge of special relativity and non-relativistic quantum mechanics, it presents all aspects of the field, including step-by-step explanations of the theory and the most recent experimental results. Taking a pedagogical, first-principles approach, it demonstrates the essential tools for students to process and analyse experimental particle physics data for themselves. While relatively short compared to other texts, it provides enough material to be covered comfortably in a two-semester course. Some of the more technical details are given in optional supplementary boxes, while problems are provided at the end of each chapter. Written as a bridge between basic descriptive books and purely theoretical works, this text offers instructors ample flexibility to meet the needs of their courses.

Akın Oktav, M. A. Başaran, Fatih Darıcık

Abstract The dynamic response of a thermoplastic composite sandwich structure is optimized under random vibration. First, the experimental modal analysis data of a set of test samples are processed by a sequential set of statistical analysis such as descriptive statistics, factor analysis, and paired sample t-test. Then, the sample with the highest ability to represent the group is taken as the reference data. Three different computational models, which are defined according to whether the solid to be meshed is considered an area or a volume, are constructed. Modal analysis results of the computational models are compared to the reference experimental data to evaluate the performance of the models. To predict the dynamic response of the sandwich beam, it is excited through a random signal in the transverse direction. The nodal acceleration responses are computed in 17 evenly spaced points located on the upper finishing layer of the sandwich beam. Finally, a geometry optimization study is conducted to predict the optimum thicknesses of the 7 layers bonded together to form the sandwich beam. The optimum layer thicknesses that minimize the nodal accelerations at 17 evenly spaced points on the sandwich beam are computed. The current study shows that the shell model has the closest values to the experimental data compared to other models. As far as the dynamic response of a TPC sandwich structure is concerned, it is concluded that the shell model better represents the structure during the modeling phase and leads to concurrently reduced weight and nodal acceleration, when optimized.

Qismullah Yusuf, Z. Jusoh, Y. Q. Yusuf

The mastery of the writing skills is crucial, not only among the school children, but also to everyone. The use of Cooperative Learning (hereafter, CL) has become increasingly popular in recent years as pedagogy trends worldwide. It has shifted from teacher-centred to learner-centred methods. Among the methods endorsed in teaching writing is the application of CL. This research investigated the effects of CL to improve the writing skill of ninth grade students in a middle school in Kuala Lumpur. This research used the quasi experimental design, with pre-test and posttest of the narrative essays as the instruments. The data were further analysed by employing descriptive and inferential statistics. The students’ writing were scored on the five writing components, they are vocabulary, organization, grammatical accuracy and mechanics. The results showed that the students had increased in their writing scores from the pre-test to the post test after the application of CL in the class. Subsequently, the results indicate positive effects of CL in improving the writing skill of students at the school, and they are also discussed in the paper.

Anna Utkina, Andrey Kozelkov, Roman Zhuchkov et al.

The paper reports the results of a study concerned with the influence of the size of the leading edge laminar bubble on the aerodynamic characteristics of the HGR01 airfoil. The completely turbulent and transient flows are considered. The mechanism of the appearance and interaction of laminar and turbulent flow separation near the leading and trailing edges of the airfoil is studied in detail. In the paper, the dependence of aerodynamic forces on the critical Reynolds number for the HGR01 airfoil is discussed. It has been established that the separation bubble at the leading edge can only be obtained using the laminar–turbulent transition model. Fully turbulent models are not able to show this feature of the airfoil flow. Graphs of the lift coefficient as a function of the critical Reynolds number, as well as the pressure distribution as a function of the size of the laminar bubble, are shown.