3D network simulations of paper structure

2012 ◽  
Vol 27 (2) ◽  
pp. 256-263 ◽  
Author(s):  
S. Lavrykov ◽  
B. V. Ramarao ◽  
S. B. Lindström ◽  
K. M. Singh
Keyword(s):  
Fiber Network ◽  
Small Strains ◽  
Simulation Techniques ◽  
3D Network ◽  
Sheet Structure ◽  
Network Simulations ◽  
Fiber Dimensions ◽  
Pressing Operation ◽  
Paper Structure ◽  
The Impact

Abstract The structure of paper influences its properties and simulations of it are necessary to understand the impact of fiber and papermaking conditions on the sheet properties. We show a method to develop a representative structure of paper by merging different simulation techniques for the forming section and the pressing operation. The simulation follows the bending and drape of fibers over one another in the final structure and allows estimation of sheet properties without recourse to arbitrary bending rules or experimental measurements of density and/or RBA. Fibers are first modeled as jointed beams following the fluid mechanics in the forming section. The sheet structure obtained from this is representative of the wet sheet from the couch. The pressing simulation discretizes fibers into a number of solid elements around the lumen. Bonding between fibers is simulated using spring elements. The resulting fiber network was analyzed to determine its elastic modulus and deformation under small strains. The influence of fiber dimensions, namely fiber lengths, widths and thicknesses as well as bond stiffnesses on the elasticity of the network are studied. A brief account of inclusion of fines, represented by individual cubical elements is also shown.

scholarly journals Poisson's Contraction and Fiber Kinematics in Tissue: Insight From Collagen Network Simulations

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
R. C. Picu ◽  
S. Deogekar ◽  
M. R. Islam
Keyword(s):  
Mouse Skin ◽  
Tissue Mechanics ◽  
Collagen Gels ◽  
Fiber Network ◽  
Collagen Orientation ◽  
Strain Behavior ◽  
Small Strains ◽  
Confining Effect ◽  
Highly Nonlinear ◽  
Network Simulations

Connective tissue mechanics is highly nonlinear, exhibits a strong Poisson's effect, and is associated with significant collagen fiber re-arrangement. Although the general features of the stress–strain behavior have been discussed extensively, the Poisson's effect received less attention. In general, the relationship between the microscopic fiber network mechanics and the macroscopic experimental observations remains poorly defined. The objective of the present work is to provide additional insight into this relationship. To this end, results from models of random collagen networks are compared with experimental data on reconstructed collagen gels, mouse skin dermis, and the human amnion. Attention is devoted to the mechanism leading to the large Poisson's effect observed in experiments. The results indicate that the incremental Poisson's contraction is directly related to preferential collagen orientation. The experimentally observed downturn of the incremental Poisson's ratio at larger strains is associated with the confining effect of fibers transverse to the loading direction and contributing little to load bearing. The rate of collagen orientation increases at small strains, reaches a maximum, and decreases at larger strains. The peak in this curve is associated with the transition of the network deformation from bending dominated, at small strains, to axially dominated, at larger strains. The effect of fiber tortuosity on network mechanics is also discussed, and a comparison of biaxial and uniaxial loading responses is performed.

Stress-strain curve of paper revisited

2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland
Keyword(s):  
Three Dimensional ◽  
Strain Curve ◽  
Failure Behavior ◽  
Three Dimensional Model ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fiber Network ◽  
Bonding Parameters ◽  
Particle Level ◽  
The Impact

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.

scholarly journals Recurrent Multi-Fiber Network for 3D MRI Brain Tumor Segmentation

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 320
Author(s):  
Yue Zhao ◽  
Xiaoqiang Ren ◽  
Kun Hou ◽  
Wentao Li
Keyword(s):  
Brain Tumor ◽  
Network Architecture ◽  
Contextual Information ◽  
Computational Cost ◽  
Disease Diagnosis ◽  
Tumor Segmentation ◽  
Brain Tumor Segmentation ◽  
Fiber Network ◽  
3D Network ◽  
The Brain

Automated brain tumor segmentation based on 3D magnetic resonance imaging (MRI) is critical to disease diagnosis. Moreover, robust and accurate achieving automatic extraction of brain tumor is a big challenge because of the inherent heterogeneity of the tumor structure. In this paper, we present an efficient semantic segmentation 3D recurrent multi-fiber network (RMFNet), which is based on encoder–decoder architecture to segment the brain tumor accurately. 3D RMFNet is applied in our paper to solve the problem of brain tumor segmentation, including a 3D recurrent unit and 3D multi-fiber unit. First of all, we propose that recurrent units segment brain tumors by connecting recurrent units and convolutional layers. This quality enhances the model’s ability to integrate contextual information and is of great significance to enhance the contextual information. Then, a 3D multi-fiber unit is added to the overall network to solve the high computational cost caused by the use of a 3D network architecture to capture local features. 3D RMFNet combines both advantages from a 3D recurrent unit and 3D multi-fiber unit. Extensive experiments on the Brain Tumor Segmentation (BraTS) 2018 challenge dataset show that our RMFNet remarkably outperforms state-of-the-art methods, and achieves average Dice scores of 89.62%, 83.65% and 78.72% for the whole tumor, tumor core and enhancing tumor, respectively. The experimental results prove our architecture to be an efficient tool for brain tumor segmentation accurately.

Using Modeling and Simulation Techniques to Improve the Accountability and the Performance of Human Resource Management

2018 ◽  
pp. 75-112
Author(s):  
Florea Nicoleta Valentina ◽  
Manea Marinela Daniela
Keyword(s):  
Human Capital ◽  
Human Resources ◽  
Organizational Performance ◽  
Simulation Techniques ◽  
A Value ◽  
Long Run ◽  
Level Data ◽  
Strategic Role ◽  
And Performance ◽  
The Impact

The analysis of human resources function and its contribution to obtain performance dates back to the 1920s. Now, the HR is an equal partner on the board of the companies, having a strategic role in obtaining performance, thus we try to show that compensating appropriately, the human capital it will be motivated to obtain performance. This paper examines the two different visions of different managers in which the human capital is perceived as a major cost for organization and the others which perceive it as an investment on long run. In this article, we analyse the impact could have the direct costs of human capital on individual and organizational performance using samples of some variables from European level, data between 2005-2016. Data used for the different years were analysed using simulation methods. Findings of this study show consistency with the theory in the filed, bringing a value in motivation and accountability of human capital and performance obtained through human capital.

scholarly journals Practical Risk Assessment of Ground Vibrations Resulting from Blasting, Using Gene Expression Programming and Monte Carlo Simulation Techniques

2020 ◽  
Vol 10 (2) ◽  
pp. 472 ◽  
Author(s):  
Amir Mahdiyar ◽  
Danial Jahed Armaghani ◽  
Mohammadreza Koopialipoor ◽  
Ahmadreza Hedayat ◽  
Arham Abdullah ◽  
...  
Keyword(s):  
Gene Expression ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Gene Expression Programming ◽  
Sensitivity Analyses ◽  
Accurate Estimation ◽  
Blasting Operation ◽  
Simulation Techniques ◽  
Input Variables ◽  
The Impact

Peak particle velocity (PPV) is a critical parameter for the evaluation of the impact of blasting operations on nearby structures and buildings. Accurate estimation of the amount of PPV resulting from a blasting operation and its comparison with the allowable ranges is an integral part of blasting design. In this study, four quarry sites in Malaysia were considered, and the PPV was simulated using gene expression programming (GEP) and Monte Carlo simulation techniques. Data from 149 blasting operations were gathered, and as a result of this study, a PPV predictive model was developed using GEP to be used in the simulation. In order to ensure that all of the combinations of input variables were considered, 10,000 iterations were performed, considering the correlations among the input variables. The simulation results demonstrate that the minimum and maximum PPV amounts were 1.13 mm/s and 34.58 mm/s, respectively. Two types of sensitivity analyses were performed to determine the sensitivity of the PPV results based on the effective variables. In addition, this study proposes a method specific to the four case studies, and presents an approach which could be readily applied to similar applications with different conditions.

Modelling a helicopter rotor’s response to wake encounters

2004 ◽  
Vol 108 (1079) ◽  
pp. 15-26 ◽  
Author(s):  
G. R. Whitehouse ◽  
R. E. Brown
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Helicopter Rotor ◽  
Forward Speed ◽  
Transport Aircraft ◽  
Simulation Techniques ◽  
Airport Capacity ◽  
Aircraft Wake ◽  
The Impact ◽  
Rotary Wing

In recent years, various strategies for the concurrent operation of fixed-and rotary-wing aircraft have been proposed as a means of increasing airport capacity. Some of these strategies will increase the likelihood of encounters with the wakes of aircraft operating nearby. Several studies now exist where numerical simulations have been used to assess the impact of encounters with the wakes of large transport aircraft on the safety of helicopter operations under such conditions. This paper contrasts the predictions of several commonly-used numerical simulation techniques when each is used to model the dynamics of a helicopter rotor during the same idealised wake encounter. In most previous studies the mutually-induced distortion of the wakes of the rotor and the interacting aircraft has been neglected, yielding the so-called ‘frozen vortex’ assumption. This assumption is shown to be valid only when the helicopter encounters the aircraft wake at high forward speed. At the low forward speeds most relevant to near-airfield operations, however, injudicious use of the frozen vortex assumption may lead to significant errors in predicting the severity of a helicopter’s response to a wake encounter.

LOAD BALANCING FOR PARALLEL PCS NETWORK SIMULATIONS

2000 ◽  
Vol 01 (03) ◽  
pp. 173-193 ◽  
Author(s):  
AZZEDINE BOUKERCHE
Keyword(s):  
Load Balancing ◽  
Distributed Simulation ◽  
Simulation Experiments ◽  
Time Warp ◽  
Conservative Scheme ◽  
Simulation Techniques ◽  
Parallel And Distributed Simulation ◽  
Pcs Networks ◽  
Network Simulations ◽  
Stage 1

Parallel and distributed simulation techniques have been investigated in a number of studies to decrease the execution times of PCS network simulations. In this paper, we consider distributed simulation of PCS models using a two-state PCS simulation testbed which makes use of a conservative scheme at Stage 1, and of Time Warp at Stage 2, and focus upon the load balancing issue. We investigate and study several load balancing schemes for TDMA systems. Extensive simulation experiments were conducted on a cluster of workstations using a real suburban area serviced by an FCA-based PCS networks. Our results indicate clearly that careful load balancing scheme is important in the success of the PCS simulation model.

scholarly journals Parametric Performance Analysis and Energy Model Calibration Workflow Integration—A Scalable Approach for Buildings

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 621 ◽  
Author(s):  
Massimiliano Manfren ◽  
Benedetto Nastasi
Keyword(s):  
Performance Analysis ◽  
Performance Management ◽  
Model Calibration ◽  
High Efficiency ◽  
A Priori ◽  
Energy Performance ◽  
Design Phase ◽  
Operation Performance ◽  
Simulation Techniques ◽  
The Impact

High efficiency paradigms and rigorous normative standards for new and existing buildings are fundamental components of sustainability and energy transitions strategies today. However, optimistic assumptions and simplifications are often considered in the design phase and, even when detailed simulation tools are used, the validation of simulation results remains an issue. Further, empirical evidences indicate that the gap between predicted and measured performance can be quite large owing to different types of errors made in the building life cycle phases. Consequently, the discrepancy between a priori performance assessment and a posteriori measured performance can hinder the development and diffusion of energy efficiency practices, especially considering the investment risk. The approach proposed in the research is rooted on the integration of parametric simulation techniques, adopted in the design phase, and inverse modelling techniques applied in Measurement and Verification (M&V) practice, i.e., model calibration, in the operation phase. The research focuses on the analysis of these technical aspects for a Passive House case study, showing an efficient and transparent way to link design and operation performance analysis, reducing effort in modelling and monitoring. The approach can be used to detect and highlight the impact of critical assumptions in the design phase as well as to guarantee the robustness of energy performance management in the operational phase, providing parametric performance boundaries to ease monitoring process and identification of insights in a simple, robust and scalable way.

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