scholarly journals A general framework for straightforward model construction of multi-component thermodynamic equilibrium systems

2021 ◽  
Author(s):  
Nick H. J. Geertjes ◽  
Pim J. de Vink ◽  
Tim Wezeman ◽  
Albert J. Markvoort ◽  
Luc Brunsveld
Keyword(s):  
General Framework ◽  
Numerical Models ◽  
Ease Of Use ◽  
Chemical Research ◽  
Equilibrium Conditions ◽  
Molecular Systems ◽  
Reversible Reactions ◽  
General Derivation ◽  
Derivation Method ◽  
Complex Phenomena

Mathematical modelling of molecular systems helps elucidating complex phenomena in (bio)chemistry. However, equilibrium conditions in systems consisting of more than two components can typically not be analytically determined without assumptions and resulting (semi-)numerical models are not trivial to derive by the non-expert. Here we present a framework for equilibrium models that utilizes a general derivation method capable of generating custom models for complex molecular systems, based on the simple, reversible reactions describing these systems. Several molecular systems are revisited via the framework and demonstrate the simplicity, the generality and validity of the approach. The ease of use of the framework and the ability to both analyze systems and gain additional insights in the underlying parameters strongly aids the analysis and understanding of molecular equilibrium systems. This conceptual framework severely reduces the time and expertise requirements which currently impede the broad integration of these highly valuable models into chemical research.

A Two-Pronged Approach for the Assessment of Springback Variability for Sheet Metal Forming Applications

2013 ◽  
Vol 554-557 ◽  
pp. 957-965 ◽  
Author(s):  
Jérémy Lebon ◽  
Guénhaël Le Quilliec ◽  
Rajan Filomeno Coelho ◽  
Piotr Breitkopf ◽  
Pierre Villon
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Numerical Models ◽  
Low Cost ◽  
Forming Process ◽  
Metal Forming Process ◽  
Small Random Perturbations ◽  
Complex Phenomena ◽  
Bending Under Tension

Springback assessment for sheet metal forming processes is a challenging issue which requires to take into account complex phenomena (physical non linearities and uncertainties). We highlight that the stochastic analysis of metal forming process requires both a high precision and low cost numerical models and propose a two-pronged methodology to address these challenges. The deep drawing simulation process is performed using an original low cost semi-analytical approach based on a bending under tension model with a good accuracy for small random perturbations of the physical and process parameters. The springback variability analysis is performed using an efficient stochastic metamodel, namely a sparse version of the polynomial chaos expansion.

Numerical modelling of the interaction between eccrine sweat and textile fabric for the development of smart clothing

2020 ◽  
Vol 32 (5) ◽  
pp. 761-774 ◽  
Author(s):  
Ted Stephenson ◽  
Caio Carvalho Ellero ◽  
Daniel Sebastia-Saez ◽  
Oleksiy Klymenko ◽  
Angela Maria Battley ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Numerical Models ◽  
Threshold Concentration ◽  
Medical Community ◽  
Sweat Glands ◽  
Electric Signal ◽  
Content Type ◽  
Concentration Threshold ◽  
Complex Phenomena ◽  
Eccrine Sweat

PurposeLive non-invasive monitoring of biomarkers is of great importance for the medical community. Moreover, some studies suggest that there is a substantial business gap in the development of mass-production commercial sweat-analysing wearables with great revenue potential. The objective of this work is to quantify the concentration of biomarkers that reaches the area of the garment where a sensor is positioned to advance the development of commercial sweat-analysing garments.Design/methodology/approachComputational analysis of the microfluidic transport of biomarkers within eccrine sweat glands provides a powerful way to explore the potential for quantitative measurements of biomarkers that can be related to the health and/or the physical activity parameters of an individual. The numerical modelling of sweat glands and the interaction of sweat with a textile layer remain however rather unexplored. This work presents a simulation of the production of sweat in the eccrine gland, reabsorption from the dermal duct into the surrounding skin and diffusion within an overlying garment.FindingsThe model represents satisfactorily the relationship between the biomarker concentration and the flow rate of sweat. The biomarker distribution across an overlying garment has also been calculated and subsequently compared to the minimum amount detectable by a sensor previously reported in the literature. The model can thus be utilized to check whether or not a given sensor can detect the minimum biomarker concentration threshold accumulated on a particular type of garment.Originality/valueThe present work presents to the best of our knowledge, the earliest numerical models of the sweat gland carried out so far. The model describes the flow of human sweat along the sweat duct and on to an overlying piece of garment. The model considers complex phenomena, such as reabsorption of sweat into the skin layers surrounding the duct, and the structure of the fibres composing the garment. Biomarker concentration maps are obtained to check whether sensors can detect the threshold concentration that triggers an electric signal. This model finds application in the development of smart textiles.

Personality and depression: A multilevel perspective

1995 ◽  
Vol 9 (5) ◽  
pp. 401-412
Author(s):  
P. Joop Heltema
Keyword(s):  
Social Behaviour ◽  
General Framework ◽  
Self Regulation ◽  
Personality Psychology ◽  
Multilevel Approach ◽  
Multilevel Perspective ◽  
Complex Phenomena ◽  
Different Levels

In personality psychology, depression is currently studied from different, largely unrelated, perspectives. This paper argues that our understanding of complex phenomena such as depression may benefit from a multilevel approach, ordering and connecting the findings obtained at different levels of inquiry. Not only can findings at a particular level be explained in terms of the lower levels, but this approach can also provide a framework for integration. Depression is examined at different levels, including genes, neurology, biochemistry, physiology, learning, social behaviour, and traits. Several interlevel connections are indicated. The findings are discussed in the context of self‐regulation as a general framework.

scholarly journals SEMI-FERMIONIC REPRESENTATION FOR SPIN SYSTEMS UNDER EQUILIBRIUM AND NON-EQUILIBRIUM CONDITIONS

2006 ◽  
Vol 20 (04) ◽  
pp. 381-421 ◽  
Author(s):  
M. N. KISELEV
Keyword(s):  
Spin Systems ◽  
Distribution Functions ◽  
Strongly Correlated ◽  
Imaginary Time ◽  
Special Shape ◽  
Equilibrium Conditions ◽  
Occupation Numbers ◽  
General Derivation ◽  
Fermionic Representation ◽  
Keldysh Technique

We present a general derivation of semi-fermionic representation for spin operators in terms of a bilinear combination of fermions in real and imaginary time formalisms. The constraint on fermionic occupation numbers is fulfilled by means of imaginary Lagrange multipliers resulting in special shape of quasiparticle distribution functions. We show how Schwinger–Keldysh technique for spin operators is constructed with the help of semi-fermions. We demonstrate how the idea of semi-fermionic representation might be extended to the groups possessing dynamic symmetries. We illustrate the application of semi-fermionic representations for various problems of strongly correlated and mesoscopic physics.

The Use of Artistic Analogies in Chemical Research and Education, Part 2

Leonardo ◽  
2007 ◽  
Vol 40 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Balazs Hargittai ◽  
Magdolna Hargittai
Keyword(s):  
Periodic Table ◽  
College Level ◽  
Chemical Research ◽  
Molecular Systems ◽  
Outreach Programs ◽  
Chemistry Textbooks ◽  
Chemical Concept ◽  
Research And Education

This compilation presents examples of artistic artifacts that have served as successful visual analogies to aspects of chemistry. The authors have used them in various college-level chemistry classes, outreach programs and chemistry textbooks, as well as in journals and monographs. They include ancient Chinese, Turkish and Thai sculptures, modern sculptures and a medieval fresco. These examples illustrate the chemical concept of chirality, the periodic table of the elements and molecular systems such as buckminsterfullerene, nanotubes and quasicrystals.

scholarly journals VAPOR: A Visualization Package Tailored to Analyze Simulation Data in Earth System Science

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 488 ◽  
Author(s):  
Shaomeng Li ◽  
Stanislaw Jaroszynski ◽  
Scott Pearse ◽  
Leigh Orf ◽  
John Clyne
Keyword(s):  
Numerical Models ◽  
Large Data ◽  
General Purpose ◽  
Ease Of Use ◽  
Earth System ◽  
Simulation Data ◽  
Domain Specific ◽  
3D Data ◽  
Commodity Computing ◽  
The Rich

Visualization is an essential tool for analysis of data and communication of findings in the sciences, and the Earth System Sciences (ESS) are no exception. However, within ESS, specialized visualization requirements and data models, particularly for those data arising from numerical models, often make general purpose visualization packages difficult, if not impossible, to use effectively. This paper presents VAPOR: a domain-specific visualization package that targets the specialized needs of ESS modelers, particularly those working in research settings where highly-interactive exploratory visualization is beneficial. We specifically describe VAPOR’s ability to handle ESS simulation data from a wide variety of numerical models, as well as a multi-resolution representation that enables interactive visualization on very large data while using only commodity computing resources. We also describe VAPOR’s visualization capabilities, paying particular attention to features for geo-referenced data and advanced rendering algorithms suitable for time-varying, 3D data. Finally, we illustrate VAPOR’s utility in the study of a numerically- simulated tornado. Our results demonstrate both ease-of-use and the rich capabilities of VAPOR in such a use case.

scholarly journals VAPOR: A Visualization Package Tailored to Analyze Simulation Data in Earth System Science

2019 ◽  
Author(s):  
Shaomeng Li ◽  
Stanislaw Jaroszynski ◽  
Scott Pearse ◽  
Leigh Orf ◽  
John Clyne
Keyword(s):  
Numerical Models ◽  
Large Data ◽  
General Purpose ◽  
Ease Of Use ◽  
Earth System ◽  
Simulation Data ◽  
Earth System Science ◽  
System Science ◽  
3D Data ◽  
The Rich

Visualization is an essential tool for analysis of data and communication of findings in the sciences, and the Earth System Science (ESS) are no exception. However, within ESS specialized visualization requirements and data models --- particularly for those data arising from numerical models --- often make general-purpose visualization packages difficult, if not impossible, to effectively use. This paper presents VAPOR: a domain-specific visualization package that targets the specialized needs of ESS modelers, particularly those working in research settings where highly interactive exploratory visualization is beneficial. We specifically describe VAPOR’s ability to handle ESS simulation data from a wide variety of numerical models, as well as a multi-resolution representation that enables interactive visualization on very large data while using only commodity computing resources. We also describe VAPOR’s visualization capabilities, paying particular attention to features for geo-referenced data and advanced rendering algorithms suitable for time-varying, 3D data. Finally, we illustrate VAPOR's utility in the study of a numerically simulated tornado. Our results demonstrate both ease-of-use and the rich capabilities of VAPOR in such a use case.

Flow Velocity Investigation by Particle Image Velocimetry in Supersonic Air Ejector

2012 ◽  
Vol 232 ◽  
pp. 256-260 ◽  
Author(s):  
Ala Bouhanguel ◽  
Philippe Desevaux ◽  
Yannick Bailly ◽  
Laurent Girardot
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Visualization ◽  
Particle Image ◽  
Numerical Models ◽  
Operating Conditions ◽  
Image Velocimetry ◽  
Air Ejector ◽  
Complex Phenomena ◽  
Physical Phenomena ◽  
Complicated Conditions

Ejectors are devices usually made of two convergent/divergent coaxial nozzles which are used to convert pressure energy into kinetic energy. These devices involve very complex phenomena which strongly affect their performance. Flow visualization methods are often used to provide precious information as for the nature of the flow within the ejectors and the comprehension of the physical phenomena encountered. Unfortunately, the visualization methods used successfully until now in these systems are primarily qualitative techniques. Some attempts at quantitative flow visualization by Particle Image Velocimetry have been carried out in quite specific applications but with mitigated results due to the complicated conditions of investigation. The objective of this paper is to present an attempt at PIV measurements in a supersonic air ejector. Several ejector operating conditions and flow seeding methods are taken into consideration. The velocity fields obtained are compared with CFD simulations of the flow and allow the rigorous validation of numerical models.

Numerical modeling strategy for deteriorated concrete decks in SHM applications

2021 ◽  
Author(s):  
Marco Andrea Pisani ◽  
Maria Pina Limongelli ◽  
Pier Francesco Giordano ◽  
Mattia Palermo
Keyword(s):  
Reinforced Concrete ◽  
Damage Identification ◽  
Numerical Models ◽  
Computational Effort ◽  
Damage Scenarios ◽  
Concrete Bridge Deck ◽  
Using Data ◽  
Girder Bridge ◽  
Modeling Strategy ◽  
Complex Phenomena

<p>The scarce availability of experimental data is a common issue faced by researchers involved in the study of vibration-based methods for damage identification in reinforced concrete structures. Such methods are often investigated and validated using data generated by numerical models where damage is simulated as a localized or global reduction of the material mechanical characteristics. In this paper, a strategy to realistically model the behavior of a cracked reinforced concrete bridge deck is proposed. This modeling strategy, albeit relatively straightforward to implement, allows to consider several complex phenomena and at the same time does not entail heavy computational effort. The modeling strategy is applied to simulate the dynamic behavior of a reinforced concrete multiple T-section girder bridge. Several types of damages are simulated and the sensitivity of modal frequencies and load-carrying capacity to different damage scenarios is investigated.</p>

Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 610-613
Author(s):  
M.G. Baldini ◽  
S. Morinaga ◽  
D. Minasian ◽  
R. Feder ◽  
D. Sayre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Biology ◽  
Imaging Technique ◽  
Human Platelets ◽  
X Rays ◽  
X Ray ◽  
X Ray Imaging ◽  
Complex Phenomena ◽  
Scanning Electron

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

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