scholarly journals An Integrated Thermal-Electrical Model for Simulations of Battery Behavior in CubeSats

2021 ◽  
Vol 11 (4) ◽  
pp. 1554
Author(s):  
Sara Vega Martinez ◽  
Edemar Morsch Filho ◽  
Laio Oriel Seman ◽  
Eduardo Augusto Bezerra ◽  
Vicente de Paulo Nicolau ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Simulation Model ◽  
Temperature Control ◽  
Integrated Model ◽  
Energy Conditions ◽  
Electrical Model ◽  
Photovoltaic Panels ◽  
Electrical Simulation ◽  
Proposed Model ◽  
Harvesting Process

This work presents an integrated thermal-electrical simulation model, capable of taking into account the thermal and electrical effects of the battery and photovoltaic panels for each instant of time in a given orbit and attitude. Using the physical equations that govern the thermal and electrical models involved during a CubeSat operation, the proposed integrated model can estimate the temperature and energy conditions of the battery, not only in an isolated way but also in considering the mutual effects on the system. Besides, special attention is given to photovoltaic panels used in the energy harvesting process, whose performance is affected by irradiance and temperature along the orbit. The integrated model can be useful for engineers when developing the subsystems of their CubeSats, taking into account, for example, the battery temperature control through a heater. Simulations were performed to illustrate the functioning of the proposed model with variations in the power requirements of its modules and the temperature of the battery throughout the orbit, and a heater’s influence on it.

scholarly journals Improved Modeling of a Multi-Level Inverter for TACS to Reduce Computational Time and Improve Accuracy

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 849
Author(s):  
Sung-An Kim
Keyword(s):  
Mechanical Model ◽  
Simulation Software ◽  
Computational Time ◽  
Electrical Model ◽  
Conventional Model ◽  
Switching Operation ◽  
Air Compressor ◽  
Power Semiconductors ◽  
Proposed Model ◽  
Multi Level

A modeling of a turbo air compressor system (TACS), with a multi-level inverter for driving variable speed, combining an electrical model of an electric motor drive system (EMDS) and a mechanical model of a turbo air compressor, is essential to accurately analyze dynamics characteristics. Compared to the mechanical model, the electrical model has a short sampling time due to the high frequency switching operation of the numerous power semiconductors inside the multi-level inverter. This causes the problem of increased computational time for dynamic characteristics analysis of TACS. To solve this problem, the conventional model of the multi-level inverter has been proposed to simplify the switching operation of the power semiconductors, however it has low accuracy because it does not consider pulse width modulation (PWM) operation. Therefore, this paper proposes an improved modeling of the multi-level inverter for TACS to reduce computational time and improve the accuracy of electrical and mechanical responses. In order to verify the reduced computational time of the proposed model, the conventional model using the simplified model is compared and analyzed using an electronic circuit simulation software PSIM. Then, the improved accuracy of the proposed model is verified by comparison with the experimental results.

scholarly journals Numerical Investigation for the Resin Filling Behavior during Ultraviolet Nanoimprint Lithography of Subwavelength Moth-Eye Nanostructure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yuanchi Cui ◽  
Xuewen Wang ◽  
Chengpeng Zhang ◽  
Jilai Wang ◽  
Zhenyu Shi
Keyword(s):  
Simulation Model ◽  
Nanoimprint Lithography ◽  
Cfd Simulation ◽  
Boundary Slip ◽  
Accurate Analysis ◽  
Inlet Velocity ◽  
Filling Height ◽  
Proposed Model ◽  
Good Consistency ◽  
Computational Fluid Dynamics Cfd

Accurate analysis of the resin filling process into the mold cavity is necessary for the high-precision fabrication of moth-eye nanostructure using the ultraviolet nanoimprint lithography (UV-NIL) technique. In this research, a computational fluid dynamics (CFD) simulation model was proposed to reveal resin filling behavior, in which the effect of boundary slip was considered. By comparison with the experimental results, a good consistency was found, indicating that the simulation model could be used to analyze the resin filling behavior. Based on the proposed model, the effects of process parameters on resin filling behavior were analyzed, including resin viscosity, inlet velocity and resin thickness. It was found that the inlet velocity showed a more significant effect on filling height than the resin viscosity and thickness. Besides, the effects of boundary conditions on resin filling behavior were investigated, and it was found the boundary slip had a significant influence on resin filling behavior, and excellent filling results were obtained with a larger slip velocity on the mold side. This research could provide guidance for a more comprehensive understanding of the resin filling behavior during UV-NIL of subwavelength moth-eye nanostructure.

Heating Performance Research in the Running-In Process of Wet Friction Clutch

2014 ◽  
Vol 614 ◽  
pp. 12-15
Author(s):  
Yu Fei Liu ◽  
Xiu Chao Bai ◽  
Xin Li ◽  
Yong Liang Lei
Keyword(s):  
Simulation Model ◽  
Temperature Control ◽  
Temperature Rise ◽  
Analysis Model ◽  
Heating Performance ◽  
Wet Friction ◽  
Friction Clutch ◽  
Simulation Results ◽  
Model Of Friction ◽  
Performance Research

The heating in the running-in process of wet friction clutch is the key to research in this kind of products. In this paper, based on the shifting clutch composed of metal and paper-based friction liner, using MATLAB/SIMULINK software, the simulation model of friction clutch and the analysis model of conducting heat were established. Thus, the corresponding relationships were obtained, which were the total friction power and clutch temperature variation with the time during the running-in process. According to the simulation results, the main influencing factors on temperature control of wet friction clutch were analyzed during running-in process, and the results could provide reference for reasonable temperature rise control for the clutch.

Temperature Control Planning Tool for Multi-Lift Resurfacing of Airport Pavements

2019 ◽  
Vol 2673 (7) ◽  
pp. 380-389 ◽  
Author(s):  
Longjia Chu ◽  
Baihe Zhu ◽  
T. F. Fwa
Keyword(s):  
Simulation Model ◽  
Temperature Control ◽  
Time Variation ◽  
Time Window ◽  
Asphalt Mixture ◽  
Time Lapse ◽  
Planning Tool ◽  
Time Duration ◽  
Deformation And Failure ◽  
Temperature Time

Overnight repairs and resurfacing of runway or taxiway pavements are common in busy airports. The time window available for such repair and resurfacing works is often limited. A common problem encountered is to ensure that the newly compacted asphalt mixture has cooled down sufficiently before receiving aircraft loadings, so as to avoid premature deformation and failure of the asphalt mixture. In this regard, a simulation model that provides a prediction of the temperature–time variation trend of each compacted pavement lift in a multi-lift asphalt course laying would be a valuable planning tool for temperature control. Information on the temperature cooling trend of an asphalt layer helps to estimate the time duration available for effective compaction during laying, as well as the time lapse needed before the pavement is sufficiently stable to receive traffic. A finite element simulation model is presented in this study to predict the temperature–time variation trends of successive asphalt lifts in a multi-lift asphalt mixture laying operation. The numerical model was developed based on the theory of thermodynamics taking into account the heat transfer effects of solar radiation, convection, and conduction. The model was calibrated and validated using data from a field trial involving a two-lift and a three-lift laying of asphalt mixtures. Illustrative examples are presented to demonstrate the applications of the simulation model as a temperature control planning tool for repair and resurfacing operations of airport pavements.

scholarly journals A Novel Approach for Forest Fragmentation Susceptibility Mapping and Assessment: A Case Study from the Indian Himalayan Region

2021 ◽  
Vol 13 (20) ◽  
pp. 4090
Author(s):  
Amit Kumar Batar ◽  
Hideaki Shibata ◽  
Teiji Watanabe
Keyword(s):  
Forest Fragmentation ◽  
Integrated Model ◽  
Himalayan Region ◽  
Geographical Information ◽  
Susceptibility Map ◽  
Forest Landscape ◽  
Indian Himalayan Region ◽  
Proposed Model ◽  
Causative Factors ◽  
The Future

An estimation of where forest fragmentation is likely to occur is critically important for improving the integrity of the forest landscape. We prepare a forest fragmentation susceptibility map for the first time by developing an integrated model and identify its causative factors in the forest landscape. Our proposed model is based upon the synergistic use of the earth observation data, forest fragmentation approach, patch forests, causative factors, and the weight-of-evidence (WOE) method in a Geographical Information System (GIS) platform. We evaluate the applicability of the proposed model in the Indian Himalayan region, a region of rich biodiversity and environmental significance in the Indian subcontinent. To obtain a forest fragmentation susceptibility map, we used patch forests as past evidence of completely degraded forests. Subsequently, we used these patch forests in the WOE method to assign the standardized weight value to each class of causative factors tested by the Variance Inflation Factor (VIF) method. Finally, we prepare a forest fragmentation susceptibility map and classify it into five levels: very low, low, medium, high, and very high and test its validity using 30% randomly selected patch forests. Our study reveals that around 40% of the study area is highly susceptible to forest fragmentation. This study identifies that forest fragmentation is more likely to occur if proximity to built-up areas, roads, agricultural lands, and streams is low, whereas it is less likely to occur in higher altitude zones (more than 2000 m a.s.l.). Additionally, forest fragmentation will likely occur in areas mainly facing south, east, southwest, and southeast directions and on very gentle and gentle slopes (less than 25 degrees). This study identifies Himalayan moist temperate and pine forests as being likely to be most affected by forest fragmentation in the future. The results suggest that the study area would experience more forest fragmentation in the future, meaning loss of forest landscape integrity and rich biodiversity in the Indian Himalayan region. Our integrated model achieved a prediction accuracy of 88.7%, indicating good accuracy of the model. This study will be helpful to minimize forest fragmentation and improve the integrity of the forest landscape by implementing forest restoration and reforestation schemes.

Development of a Simulation Model for Optimization of Business Process

2018 ◽  
pp. 26-42
Keyword(s):  
Simulation Model ◽  
Model Validation ◽  
Business Process ◽  
Research Question ◽  
Future Research ◽  
The Novel ◽  
Model Based ◽  
Model Validity ◽  
Proposed Model ◽  
New Research

Optimization of business process assists in efficient organization of business process. For the success of optimization of business process, a simulation model based on gap processes for the analysis of buyers' burstiness in business process has been proposed. However, the model has to be validated. The aim of the research is to implement a validation approach to the simulation model based on gap processes for the optimization of business process underpinning elaboration of a new research question on the model validity. The meaning of the key concepts of “validation,” “model validation,” and “model validation approach” is studied. The results of the present research show that the application of real system measurements validates the simulation model for the optimization of business process. The novel contribution of the manuscript is revealed in the newly created research question on the proposed model validity. Directions of future research are proposed.

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