Concept Of Momentum Research Articles

Interaction of a Dense Layer of Solid Particles with a Shock Wave Propagating in a Tube

A numerical simulation of an unsteady gas flow containing inert solid particles in a shock tube is carried out using the interpenetrating continuum model. The gas and dispersed phases are characterized by governing equations that express the concepts of mass, momentum, and energy conservation as well as an equation that shows the change of the volume fraction of the dispersed phase. Using a Godunov-type approach, the hyperbolic governing equations are solved numerically with an increased order of accuracy. The working section of the shock tube containing air and solid particles of various sizes is considered. The shock wave structure is discussed and computational results provide the spatial and temporal dependencies of the particle concentration and other flow quantities. The numerical simulation results are compared with available experimental and computational data.

Lattice generation utilizing fractional Talbot effect and high-order orbital angular momentum optical vortices

The concept of orbital angular momentum (OAM) has garnered significant attention from researchers since its discovery, with a steady uncovering of its properties over the past three decades. Initially overlooked, the role of OAM in the optical vortex lattice (OVL) has gained prominence due to recent scholarly efforts. This study delves into the modification of OAM by employing controlled topological charge to generate high-order OVL. Furthermore, it explores the Talbot effect within the context of multi-beam interference. The findings indicate that the interference of three beams of light results in the formation of both Kagome and Super-honeycomb lattices, whereas the interference of four beams leads to the emergence of the Lieb lattice. This research offers novel insights into light interference and light field regulation and its application.

Generalized [formula omitted]-sparse algorithms for constructing fault tolerant RBF networks

In the construction process of radial basis function (RBF) networks, two common crucial issues arise: the selection of RBF centers and the effective utilization of the given source without encountering the overfitting problem. Another important issue is the fault tolerant capability. That is, when noise or faults exist in a trained network, it is crucial that the network’s performance does not undergo significant deterioration or decrease. However, without employing a fault tolerant procedure, a trained RBF network may exhibit significantly poor performance. Unfortunately, most existing algorithms are unable to simultaneously address all of the aforementioned issues. This paper proposes fault tolerant training algorithms that can simultaneously select RBF nodes and train RBF output weights. Additionally, our algorithms can directly control the number of RBF nodes in an explicit manner, eliminating the need for a time-consuming procedure to tune the regularization parameter and achieve the target RBF network size. Based on simulation results, our algorithms demonstrate improved test set performance when more RBF nodes are used, effectively utilizing the given source without encountering the overfitting problem. This paper first defines a fault tolerant objective function, which includes a term to suppress the effects of weight faults and weight noise. This term also prevents the issue of overfitting, resulting in better test set performance when more RBF nodes are utilized. With the defined objective function, the training process is designed to solve a generalized M-sparse problem by incorporating an ℓ0-norm constraint. The ℓ0-norm constraint allows us to directly and explicitly control the number of RBF nodes. To address the generalized M-sparse problem, we introduce the noise-resistant iterative hard thresholding (NR-IHT) algorithm. The convergence properties of the NR-IHT algorithm are subsequently discussed theoretically. To further enhance performance, we incorporate the momentum concept into the NR-IHT algorithm, referring to the modified version as “NR-IHT-Mom”. Simulation results show that both the NR-IHT algorithm and the NR-IHT-Mom algorithm outperform several state-of-the-art comparison algorithms.

Efficient generation of octave-separating orbital angular momentum beams via forked grating array in lithium niobite crystal

Abstract The concept of orbital angular momentum (OAM) of light has not only advanced fundamental physics research but also yielded a plethora of practical applications, benefitting from the abundant methods for OAM generation based on linear, nonlinear and combined schemes. The combined scheme could generate octave-separating OAM beams, potentially increasing the channels for optical communication and data storage. However, this scheme faces a challenge in achieving high conversion efficiency. In this work, we have demonstrated the generation of multiple OAM beams at both fundamental frequency and second harmonic (SH) wavelengths using a three-dimensional forked grating array with both spatial χ (1) and χ (2) distributions in a lithium niobate nonlinear photonic crystal platform. The enhancements of the fundamental and SH OAM beams have been achieved by employing linear Bragg diffraction and nonlinear Bragg diffraction, respectively, i.e., quasi-phase matching. The experimental results show that OAM beams with variable topological charges can be enhanced at different diffraction orders via wavelength or angle tuning, achieving conversion efficiencies of 60.45 % for the linear OAM beams and 1.08 × 10−4 W −1 for the nonlinear ones. This work provides a promising approach for parallel detection of OAM states in optical communications, and extends beyond OAM towards the control of structured light via cascaded linear and nonlinear processes.

Grasp the Momentum: Define and Prediction Models for Accurate Trend

In tennis, the concept of momentum is used to describe the reversal of a player's big lead. However, motivation in sports is subjective and difficult to quantify. To address this challenge, the study aims to build models that can predict momentum and successful streaks. We accomplished three main tasks. Task one involves assessing player motivation using a variety of metrics and analytic hierarchy process (AHP). Task two includes proving strong autocorrelation and testing fringes using run tests. The results show significant autocorrelation, which is suitable for momentum regression prediction. In Mission three, the random forest method is used to calculate the importance of features to provide suggestions for the player's next game. The long short-term memory (LSTM) model is used to predict the trend of the next game and the momentum of the players, showing good reliability and accuracy. The sensitivity analysis and robustness verification show that it is consistent with the actual situation and the error range is acceptable. Finally, the advantages and disadvantages of the model are summarized, and suggestions for further improvement are put forward.

Space-Based Passive Orbital Maneuver Detection Algorithm for High-Altitude Situational Awareness

Orbital maneuver detection for non-cooperative targets in space is a key task in space situational awareness. This study develops a passive maneuver detection algorithm using line-of-sight angles measured by a space-based optical sensor, especially for targets in high-altitude orbit. Emphasis is placed on constructing a new characterization for maneuvers as well as the corresponding detection method. First, the concept of relative angular momentum is introduced to characterize the orbital maneuver of the target quantitatively, and the sensitivity of the proposed characterization is analyzed mathematically. Second, a maneuver detection algorithm based on the new characterization is designed in which sliding windows and correlations are utilized to determine the mutation of the maneuver characterization. Subsequently, a numerical simulation system composed of error models, reference missions and trajectories, and computation models for estimating errors is established. Then, the proposed algorithm is verified through numerical simulations for both long-range and close-range targets. The results indicate that the proposed algorithm is effective. Additionally, the sensitivity of the proposed algorithm to the width of the sliding window, accuracy of the optical sensor, magnitude and number of maneuvers, and different relative orbit types is analyzed, and the sensitivity of the new characterization is verified using simulations.

Unveiling the Deep Connection Between Athlete Momentum and Match Scoring through Statistics Analysis

The concept of momentum in ball sports is characterized by significant changes in-game performance and mental states, which play a key role in determining the outcome of a match. This study takes the 2023 Wimbledon men's final as an example and constructs a model for assessing athletes' performance during tennis matches based on binary logistic regression. It also constructs a tennis match momentum assessment algorithm to explore the relationship between the momentum change among match players and the performance change (score difference) of both players. It was found that the momentum change of match players was closely related to the score difference. This study is not only conducive to improving the athletes' competitive level but also has a profound impact on the scientific and professional development of tennis.

Quantification of momentum in tennis matches and its impact: a study based on AHP-EWM method and data analysis

Tennis is a globally popular sport that tests players' abilities in all aspects, including mental quality. In tennis, momentum is a psychological phenomenon that reflects the strengths and weaknesses of players. It affects players' mentality, performance, and match results. However, there are still some inadequacies and controversies in the current research on momentum, such as its concept, formation mechanism, quantification method, and actual effect. This study deeply analyzes the concept and formation mechanism of momentum in tennis matches and its influence on the result of the match. Through a combination of data analysis and quantitative methods, this study reveals the importance of momentum changes on player performance and match results. Through the application of AHP-EWM, Welch's T-Test, and Run Test, this paper not only quantifies momentum but also confirms the significance and non-randomness of momentum, refuting the traditional views on the randomness of competition performance fluctuation and success rate. The results of this study not only provide a new perspective for understanding the strategy and dynamics of tennis matches, but also provide practical guidance for athletes' training and competition preparation. In addition, the methodology and findings of this study also have reference value for other sports that need to analyze the impact of momentum, opening up a new path for future sports science research.

From immune equilibrium to tumor ecodynamics.

There is no theory to quantitatively describe the complex tumor ecosystem. At the same time, cancer immunotherapy is considered a revolution in oncology, but the methods used to describe tumors and the criteria used to evaluate efficacy are not keeping pace. The purpose of this study is to establish a new theory for quantitatively describing the tumor ecosystem, innovating the methods of tumor characterization, and establishing new efficacy evaluation criteria for cancer immunotherapy. Based on the mathematization of immune equilibrium theory and the establishment of immunodynamics in a previous study, the method of reverse immunodynamics was used, namely, the immune braking force was regarded as the tumor ecological force and the immune force was regarded as the tumor ecological braking force, and the concept of momentum in physics was applied to the tumor ecosystem to establish a series of tumor ecodynamic equations. These equations were used to solve the fundamental and applied problems of the complex tumor ecosystem. A series of tumor ecodynamic equations were established. The tumor ecological momentum equations and their component factors could be used to distinguish disease progression, pseudoprogression, and hyperprogression in cancer immunotherapy. On this basis, the adjusted tumor momentum equations were established to achieve the equivalence of tumor activity (including immunosuppressive activity and metabolic activity) and tumor volume, which could be used to calculate individual disease remission rate and establish new efficacy evaluation criteria (ieRECIST) for immunotherapy of solid tumor based on tumor ecodynamics. At the same time, the concept of moving cube-to-force square ratio and its expression were proposed to calculate the area under the curve of tumor ecological braking force of blood required to achieve an individual disease remission rate when the adjusted tumor ecological momentum was known. A new theory termed tumor ecodynamics emphasizing both tumor activity and tumor volume is established to solve a series of basic and applied problems in the complex tumor ecosystem. It can be predicted that the future will be the era of cancer immune ecotherapy that targets the entire tumor ecosystem.

Research on Tennis Match Strategies Based on Machine Learning and Markov Chain Modeling

This paper mainly studies the influence of athletes' performance on the results of sports competitions, and uses advanced data analysis and machine learning technology to predict the players' scoring patterns in tennis matches. Firstly, the Markov chain model is used to capture match points and game flow. In order to quantify player performance, the concept of momentum is introduced. The random forest model based on factor analysis optimization studies the factors affecting player performance. Secondly, the random forest model optimized by firefly algorithm is used to select the factors that may affect the competition, identify the important factors and data that affect the fluctuation of the competition, and realize the prediction. This study provides an advanced perspective on sports analytics, providing actionable insights for athletes and coaches to refine their strategies and gain a competitive edge, while also providing lessons for the development of sports analytics and data-driven decision making.

Identification of Students' Misconceptions using Four-Tier Diagnostic Assessment in Physics Learning Phase F

This research aims to identify students' misconceptions about momentum and impulse material using a four-tier diagnostic assessment instrument to implement learning evaluation in the Merdeka curriculum. This type of research is descriptive with a qualitative approach, with data collection techniques carried out through assessments and interviews. Interview data is used to reinforce assessment data. The instrument used in the study is a four-tier diagnostic test on momentum and impulse developed by the researchers. The results showed that 50% of students experienced misconceptions about momentum matter due to the assumption that if two objects move with the same kinetic energy should have the same speed so that the momentum of both objects can be determined by ignoring their velocity. Then, as many as 13. 9% of students experience misconceptions about the law of conservation of matter momentum because of students' assumptions that ignore direction on velocity vector quantities. In other physics concepts, some students are less careful in calculations. The results of this study are expected to be a reference for teachers in designing more meaningful Merdeka curriculum-based learning plans to help students better understand the concepts of momentum and impulse.

Импульс мобилизации и электоральные результаты «партии власти»

The article examines the connection between protests and elections in an authoritarian context. Using the concept of mobilization momentum, the authors attempt to find out whether intensive and massive collective actions on the eve of elections can affect electoral mobilization and support for the “party in power”, and if so, in what direction. Based on the modern literature on this topic, the authors identify two alternative models of the possible electoral effect of the mobilization momentum. According to the first model, by breaking through the information blockade and signaling to citizens about the widespread dissatisfaction with the authorities’ policies, intense mass protests contribute to an increase in voters’ turnout and a decrease in support for pro-government forces. According to the second model, such protests may easily increase the electoral performance of the “party in power,” since they often lead to the mobilization of an electorate that is loyal to the ruling circles. The authors test these hypotheses against the evidence from the 2011— 2016 parliamentary electoral cycle in Russia using methods of standard multiple linear regression, difference-in-differences and synthetic control. The results are mixed. It appears that the mobilization momentum has a weak electoral effect or even a positive effect on the performance of the “party in power,” but its influence may depend on threshold values: in the most protesting cities, support for the United Russia turns out to be lower than it would be in the absence of the mobilization momentum. At the same time, the findings convincingly demonstrate that the evidence and data from the Russian context, combined with modern methods of analysis, opens up an excellent opportunity for research at the intersection of the spheres of political participation and electoral politics.

Development of a Two-Tier Diagnostic Test for The Analysis of Momentum and Impulse Learning Difficulties in Students

This study aimed to develop a formation test that also serves as a diagnostic test. The purpose of this product is to determine students’ learning difficulty levels. We used a two-step multiple-choice assessment tool to develop this diagnostic test. Because two-step multiple-choice tests help teachers identify learning difficulties that arise in students. The research method used is research and development. This test was developed using the Moodle platform and takes the form of a closed multiple-choice test consisting of 20 questions. Media and materials experts validate diagnostic tests. Based on validation, this developed product can be used as a physics learning assessment tool to measure student learning outcomes and learning difficulties. The aspects of media learning expert is usability, navigation, visuals, product, effectiveness, and content. While, the aspects of material expert are compliance with curriculum, construction, and language. We tested high school students and found that 2 of the 20 questions about the concepts of momentum and impulse were mastered and the remaining 18 were at the level of instrumental understanding and misunderstanding. Therefore, teachers should look for strategies to expand students' conceptual knowledge of dynamics and momentum. Thus, the mastery of the student's concept is whole and thorough.

Analysis of Science-Physics Concept According to The Independent Curriculum in the Traditional Boi Game

An ancient game that has often been played from generation to generation in the Maluku region is the boi game. The boi game can be used as science-physics learning material according to the curriculum in force at school in the hope that it can make the learning process effective and efficient. This research aims to analyze the science-physics concepts found in the traditional Boi game in Allang Village, Leihitu District, Central Maluku Regency, Maluku. The research was conducted using descriptive methods with a qualitative approach. Data collection was carried out through interviews, observations, and document studies. The results of the analysis show that when the player applies force to the ball so that the ball moves and touches the stone structure and/or touches the body of the opposing player, the concepts of kinetic energy, elasticity, momentum, impulse, collision, work, force, and displacement are identified. The position of these concepts in the independent curriculum is at the junior high school phase D and high school phase F

Enhancement of Mastery Physics Concept of Momentum and Impulse Among Class X High School Students by Implementing 8E Leaning Model

This research utilized the Physics at School application to utilize the Learning Cycle 8E model to explain students' conceptual mastery in class X SMA and identify any disparities in conceptual mastery for students in class X SMA. This kind of research uses a quantitative Nonequivalent Post-Test Control Group Design research design and a Quasi-Experimental research method. This research was performed at SMA Negeri 1 Teluk Kuantan. The aims of this research was to implement the Learning Cycle 8E model with assistance from the Physics at School program. In contrast, the second class uses conventional learning techniques as a control class. The data used in this research were concept mastery scores obtained from students who had learned physics using the Learning Cycle 8E model with assistance from the Physics at School program. Based on a descriptive and inferential examination of the data, it was found that the experimental class students' level of concept mastery increased by 73.08 points, while the control class was 69.70. Certainly, Learning Cycle 8E model, which is supported by the Physics at School application, has an impact on how well SMA Negeri 1 Teluk Kuantan children understand certain concepts.

Assessing conceptual understanding of learning in energy and momentum by using Socrative online polling in physics classes

This research investigates the understanding and learning gains of students learning between online and onsite classes on topics of Energy and Momentum. In this study, twenty-five questions relating to Energy and Momentum, including Energy Concepts, Work Done by Gravitational Forces, Work Done by Nonconservative Forces, Conservation of Mechanical Energy, Momentum Concepts, Momentum Conservation, Completely Inelastic Collisions, and Applications of the Impulse-Momentum Theorem, were used. One hundred and ninety-five students from the Faculty of Engineering at Rajamangala University of Technology Lanna, Chiang Mai campus, were tested through online and onsite learning between 2021 and 2022, respectively. The collected data were evaluated using Socrative online polls. Statistics, including average percentage, standard deviation, and the normalized gain method, were used to analyze the understanding of learning between the pre-test and post-test of online and onsite classes. The results found that after classes, the mean of correct answers for online classes was 18.76 (SD = 2.81) and 20.68 (SD = 3.19) for onsite classes. The average normalized gain <g> for online classes was 0.01, and for onsite classes was 0.05. These results demonstrated that onsite learning was more effective than online learning.

Analysis of Momentum and Impulse Misconceptions of College Students Using Four-Tier Diagnostic Tests

This research aims to discover misconceptions about momentum and impulse concepts. The research method used in this research is a mixed method. The subjects of this research were students majoring in physics from the classes of 2019, 2020, and 2021 who had taken the basic physics course I, with a total sample of 44 students. The instrument used was 15 four-level multiple diagnostic tests. Research data was obtained based on student answer patterns on a four-level multiple-choice test. The results of the research show that students' conceptual understanding of momentum and impulse material using the four-level diagnostic test is still relatively low, as seen from the percentage of students who partially understand the concept at 46%, understand the concept at 30%, negative misconceptions at 10%, positive misconceptions at 9%, and positive misconceptions at 5%. Some of the misconceptions experienced by students regarding the concepts of momentum and impulse include: first, students assume that only mass influences the amount of momentum; second, they assume that the total momentum of a system of isolated objects is not constant; third, assume that the total momentum of a system of isolated objects is not constant, the fourth assumes that two objects of the same mass have different speeds, the sixth assumes that changes in the speed of a particle are only influenced by force and time and the last, namely the seventh, assumes that the process of collisions on smooth surfaces will move all objects.

Thermodynamics of FLRW apparent horizon in the presence of UV/IR mixing

Generalized uncertainty principle (GUP) and Extended uncertainty principle (EUP) are well-known phenomenological gates to the issue of the so-called Gravitational Quantum Mechanics. Two fundamental impacts of the GUP and EUP are the concepts of minimal measurable length and minimal measurable momentum. The minimal measurable length as the possible smallest uncertainty in position measurement can remove the spacetime singularities arising from the general theory of relativity in UV regime. On the other hand, the minimal measurable momentum as the possible smallest uncertainty in momentum measurement puts an IR cutoff on the late-time (low energy) dynamics of the universe. This minimal momentum essentially arises due to the curvature of the background spacetime manifold. A combination of GUP and EUP gives a UV–IR complete uncertainty principle which is called usually as EGUP in literature. Motivated by these facts, we aim to study the impact of the EGUP with minimal measurable length and minimal measurable momentum on Friedmann equations. We first find the EGUP-modified entropy expression in Friedmann–Lemaître–Robertson–Walker (FLRW) universe. Then, we obtain the EGUP-corrected Friedmann equations by employing the unified first law of thermodynamics. We explore the deceleration parameter in the EGUP setup. We then check whether the generalized second law of thermodynamics is fulfilled and then study some related issues. As a result, we find some constraints on the EGUP parameters.

Iterative inversion of the tensor momentum x-ray transform

The momentum x-ray transform maps a symmetric tensor field f of order m in to its integrals over lines at + b with the weight tk , . In this article we propose an iterative approach to the reconstruction problem. Namely, a new concept of partial momentum transforms is introduced. These transforms are intermediaries between the momentum and the component-wise x-ray transforms. Moreover, one can use a differential operator to construct a sequence of partial momentum transforms that starts with the momentum and finishes with the component-wise transform. The latter can be inverted with the standard component-wise backprojection. The proposed method was also applied to obtain an analog of the Plancherel formula as well as the stability estimates in the Sobolev spaces that are valid for any m.

Amplify or Suppress? Top Leader Perspective on External Stakeholders' Influence on Organizational Change Outcomes

Based on a collaborative auto-ethnographic approach, this paper examines how external stakeholders can influence organizational change processes and outcomes in a public sector context. Existing change literature suggests that stakeholder management and collaboration are critical for achieving change results. Although the role of internal stakeholders has been documented, we know less about how external stakeholders can influence planned change. To explore this, we adopted a variant of collaborative auto-ethnography in which the first-hand experiences of a top manager combined with extensive media coverage were retrospectively made sense of through joint reflection and theorizing with an outside academic. Drawing on stakeholder theory and the concept of momentum for change, we show how external stakeholders can either amplify or suppress the momentum for change, thereby ultimately affecting goal attainment. The slightly adjusted CAE methodology offers new opportunities for academic/practitioner collaborations to advance change practice and theory.