Dynamic simulation and performance investigation of no-frost refrigerator: Part I mathematical model

2009 ◽  
Vol 14 (1) ◽  
pp. 40-44
Author(s):  
Xiu-ping Su ◽  
Jiang-ping Chen ◽  
Zhi-jiu Chen ◽  
Xiao-tian Zhou
Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.


2012 ◽  
Vol 246-247 ◽  
pp. 1220-1225
Author(s):  
You Kun Zhong

With the increasing of the number of cars, people are also getting higher and higher demands on the performance of the car, and especially pay attention to the improvement and optimization of automobile transmission system. The transmission is a key part of automobile transmission system, and transmission performance and stability depend on the synchronous machine, so in order to make the vehicle transmission system with higher efficiency, it is necessary to study the synchronous machine. On the basis of elaborating synchronous machine working principle, the use of dynamics theory to establish mathematical model of synchronous machine system, and to carry out the simulation of synchronous machine three-dimensional model in PRO/E environment, then the use of virtual prototype technology to optimize the parameters of synchronous machine, thereby improving the performance of synchronous machine.


1999 ◽  
Vol 8 (5) ◽  
pp. 591-600 ◽  
Author(s):  
Andrew R Johnson ◽  
William A Bullough ◽  
John Makin

Solar Energy ◽  
2021 ◽  
Vol 228 ◽  
pp. 263-273
Author(s):  
Milad Irani ◽  
Ata Chitsaz ◽  
Morteza Khalilian ◽  
Mahsa Mehrara ◽  
Kiyan Parham

Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1082
Author(s):  
Luiz Felipe da Silva ◽  
Paulo Francisco de Almeida-Neto ◽  
Dihogo Gama de Matos ◽  
Steven E. Riechman ◽  
Victor de Queiros ◽  
...  

Background: The exhaustive series of tests undergone by young athletes of Olympic rowing prior to important competitions imply loads of physical stress that can ultimately impact on mood and motivation, with negative consequences for their training and performance. Thus, it is necessary to develop a tool that uses only the performance of short distances but is highly predictive, offering a time expectancy with high reliability. Such a test must use variables that are easy to collect with high practical applicability in the daily routine of coaches. Objective: The objective of the present study was to develop a mathematical model capable of predicting 2000 m rowing performance from a maximum effort 100 m indoor rowing ergometer (IRE) test in young rowers. Methods: The sample consisted of 12 male rowing athletes in the junior category (15.9 ± 1.0 years). A 100 m time trial was performed on the IRE, followed by a 2000 m time trial 24-h later. Results: The 2000 m mathematical model to predict performance in minutes based on the maximum 100 m test demonstrated a high correlation (r = 0.734; p = 0.006), strong reliability index (ICC: 0.978; IC95%: [0.960; 0.980]; p = 0.001) and was within usable agreement limits (Bland -Altman Agreement: −0.60 to 0.60; 95% CI [−0.65; 0.67]). Conclusion: The mathematical model developed to predict 2000 m performance is effective and has a statistically significant reliability index while being easy to implement with low cost.


2013 ◽  
Vol 572 ◽  
pp. 636-639
Author(s):  
Xi Chen ◽  
Gang Wang

This paper deals with the walking stability analysis of a multi-legged crablike robot over slope using normalized energy stability margin (NESM) method in order to develop a common stabilization description method and achieve robust locomotion for the robot over rough terrains. The robot is simplified with its static stability being described by NESM. The mathematical model of static stability margin is built so as to carry out the simulation of walking stability over slope for the crablike robot that walks in double tetrapod gait. As a consequence, the relationship between stability margin and the height of the robots centroid, as well as its inclination relative to the ground is calculated by the stability criterion. The success and performance of the stability criterion proposed is verified through MATLAB simulation and real-world experiments using multi-legged crablike robot.


Author(s):  
Cheng Zhu ◽  
Tian Yu ◽  
Qing Chang ◽  
Jorge Arinez

Abstract In a multistage serial production line, products with defect can be repaired or reworked to ensure high product quality. This paper studies a multistage serial manufacturing system with quality rework loops. Rework is the activity to repair or repeat the work on the defect parts during manufacturing processes, and it adds to cost and cycle time. This paper introduces an event-based data-enabled mathematical model for a stochastic production line with quality rework loops. The system performance properties are analyzed and permanent production loss due to quality rework loops is identified. The mathematical model and system performance identification methodology are studied analytically through numerical case studies.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bin Wang ◽  
Nanyue Xu ◽  
Pengyuan Wu ◽  
Rongfei Yang

Purpose The purpose of this paper is to provide a new hydrostatic actuator controlled by a piezoelectric piston pump and to reveal its characteristics. Design/methodology/approach In this paper, a piezoelectric pump with passive poppet valves and hydraulic displacement amplifier is designed as a new control component in a hydrostatic actuator for high actuation capacity. A component-level mathematical model is established to describe the system characteristics. Simulation verification for cases under typical conditions is implemented to evaluate the delivery behavior of the pump and the carrying ability of the actuator. Findings By using the displacement amplifier and the passive distributing valves, simulation demonstrates that the pump can deliver flow rate up to 3 L/min, and the actuator controlled by this pump can push an object weighing approximately 50 kg. In addition, it is particularly important to decide a proper amplification ratio of the amplifier in the pump for better actuation performance. Originality/value The piezoelectric pump presented in this paper has its potential to light hydrostatic actuator. The model constructed in this paper is valid for characteristic analysis and performance evaluation of this pump and actuators.


2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Ibrahim A Abuashe ◽  
Bashir H Arebi ◽  
Essaied M Shuia

A mathematical model based on the momentum, continuity and energy balance equations was developed to simulate the behavior of the air flow inside the solar chimney system. The model can estimate the power output and performance of solar chimney systems. The developed mathematical model is validated by the experimental data that were collected from small pilot solar chimney; (experiment was presented in part I). Good agreement was obtained between the experimental results and that from the mathematical model. The model can be used to analyze the solar chimney systems and to determine the effect of geometrical parameters such as chimney height and collector diameter on the power output and the efficiency of the system


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