Unifying Theory for Natural and Man-Made Flow Systems: an Application to Design of Porous Material for Particulate Control

2010 ◽  
Vol 297-301 ◽  
pp. 413-421 ◽  
Author(s):  
Antonio F. Miguel
Keyword(s):  
Particulate Matter ◽  
Porous Material ◽  
High Performance ◽  
Constructal Theory ◽  
Optimal Flow ◽  
Natural Flow ◽  
Constructal Law ◽  
Flow Systems ◽  
Particulate Control

According to constructal theory, the flow architecture emerges in time such that it provides progressively greater access to its currents. The emergence of flow architecture in nature is analogous to emergence of configuration in man-made (engineered) flow systems, and that features of materialization of design can be predicted based on the constructal theory. To support this view, we show that the emergence of configuration in natural flow systems can be approached based on the constructal law. Man-made flow systems achieve high performance by acquiring the suitable architecture (configuration). In this study, we also rely on the constuctal law to design a device for particulate matter control with an optimized function. Therefore, the emergence of optimal flow architecture is analogous to both natural and man-made systems. The features of materialization of design do not occur by chance, and can be explained or predicted based on this physical law.

scholarly journals The constructal law of design and evolution in nature

2010 ◽  
Vol 365 (1545) ◽  
pp. 1335-1347 ◽  
Author(s):  
Adrian Bejan ◽  
Sylvie Lorente
Keyword(s):  
Entropy Generation ◽  
Flow Resistance ◽  
Scaling Laws ◽  
Minimum Weight ◽  
Finite Size ◽  
Maximum Flow ◽  
Constructal Theory ◽  
Minimum Entropy ◽  
Constructal Law ◽  
Flow Systems

Constructal theory is the view that (i) the generation of images of design (pattern, rhythm) in nature is a phenomenon of physics and (ii) this phenomenon is covered by a principle (the constructal law): ‘for a finite-size flow system to persist in time (to live) it must evolve such that it provides greater and greater access to the currents that flow through it’. This law is about the necessity of design to occur, and about the time direction of the phenomenon: the tape of the design evolution ‘movie’ runs such that existing configurations are replaced by globally easier flowing configurations. The constructal law has two useful sides: the prediction of natural phenomena and the strategic engineering of novel architectures, based on the constructal law, i.e. not by mimicking nature. We show that the emergence of scaling laws in inanimate (geophysical) flow systems is the same phenomenon as the emergence of allometric laws in animate (biological) flow systems. Examples are lung design, animal locomotion, vegetation, river basins, turbulent flow structure, self-lubrication and natural multi-scale porous media. This article outlines the place of the constructal law as a self-standing law in physics, which covers all the ad hoc (and contradictory) statements of optimality such as minimum entropy generation, maximum entropy generation, minimum flow resistance, maximum flow resistance, minimum time, minimum weight, uniform maximum stresses and characteristic organ sizes. Nature is configured to flow and move as a conglomerate of ‘engine and brake’ designs.

Bejan’s Constructal Theory Analysis of Gas-Liquid Cooled Finned Modules

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Giulio Lorenzini ◽  
Simone Moretti
Keyword(s):  
Thermal Behavior ◽  
Heat Exchangers ◽  
High Performance ◽  
Numerical Study ◽  
Constructal Theory ◽  
Electronic Components ◽  
Theory Analysis ◽  
Pressure Losses ◽  
Different Types ◽  
Overall Performance

High performance heat exchangers represent nowadays the key of success to go on with the trend of miniaturizing electronic components as requested by the industry. This numerical study, based on Bejan’s Constructal theory, analyzes the thermal behavior of heat removing fin modules, comparing their performances when operating with different types of fluids. In particular, the simulations involve air and water (as representative of gases and liquids), to understand the actual benefits of employing a less heat conductive fluid involving smaller pressure losses or vice versa. The analysis parameters typical of a Constructal description (such as conductance or Overall Performance Coefficient) show that significantly improved performances may be achieved when using water, even if an unavoidable increase in pressure losses affects the liquid-refrigerated case. Considering the overall performance: if the parameter called Relevance tends to 0, air prevails; if it tends to 1, water prevails; if its value is about 0.5, water prevails in most of the case studies.

scholarly journals High-performance particulate matter including nanoscale particle removal by a self-powered air filter

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Guo-Hao Zhang ◽  
Qiu-Hong Zhu ◽  
Lei Zhang ◽  
Fang Yong ◽  
Zhang Zhang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
High Performance ◽  
Particle Removal ◽  
Air Filter ◽  
Nanoscale Particle ◽  
Self Powered

Corrigendum to: Determination of Selective Quinones and Quinoid Radicals in Airborne Particulate Matter and Vehicular Exhaust Particles

2006 ◽  
Vol 3 (3) ◽  
pp. 233 ◽  
Author(s):  
Athanasios Valavanidis ◽  
Konstantinos Fiotakis ◽  
Thomais Vlahogianni ◽  
Vasilios Papadimitriou ◽  
Vayia Pantikaki
Keyword(s):  
Particulate Matter ◽  
High Performance ◽  
Airborne Particulate Matter ◽  
Oxygen Species ◽  
Airborne Particulate ◽  
Paramagnetic Resonance ◽  
Semiquinone Radicals ◽  
Polycyclic Aromatic ◽  
Exhaust Particles ◽  
Electron Paramagnetic

Environmental Context.�Fine and coarse airborne particulate matter (PM) has been linked to increases in respiratory diseases and lung cancer. PM contains a variety of compounds, such as metals, polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and quinones adsorbed in a carbonaceous polymeric matrix. Although quinones are found in small amounts in PM, they are capable of redox cycling and in the presence of oxygen catalyse the generation of reactive oxygen species (ROS) in biological systems. ROS are responsible for the induction of oxidative stress, especially oxidative damage to cellular proteins and DNA. This paper investigated quantitatively selected quinones and hydroquinones by high performance liquid chromatography in various airborne PM samples. Also, we investigated the presence of persistent semiquinone radicals in solid samples and quinoid radicals in aqueous extracts of alkaline solution by electron paramagnetic resonance spectroscopy. Abstract.�In recent years, there has been an increasing interest in the study of the health effects of respirable particulate matter (PM) because of its deposition in the human lungs and adverse health effects. Analysis of PM content focused on substances of toxicological importance, such as polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, aliphatic hydrocarbons, alkyl-substituted benzenes and naphthalenes, transition metals and various quinones. Recent studies shifted their attention to quinones and their toxicological role in PM. Quinones can be transformed into their semiquinones, which undergo redox cycling and reduce oxygen to produce reactive oxygen species (ROS) in biological systems, resulting in the induction of oxidative stress, especially oxidative damage to cellular components and DNA. In the present study, the presence of five quinones, 1,2-benzenediol (catechol) and 1,4-benzenediol (hydroquinone) in various PM samples was identified and measured quantitatively by high performance liquid chromatography. Mean concentrations of individual target quinones ranged from 15-140 ng mg-1 in diesel and gasoline exhaust particles to 1.5-60 ng mg-1 (or 150-1100 pg m-3) in airborne PM (total suspended particulates, PM aerodynamic diameter 10 μm, PM aerodynamic diameter 2.1 μm) samples. Precision (repeatability and reproducibility) varied from 5 to 15%. Also, examples of electron paramagnetic resonance spectra for the single broad unstructured signal are presented, corresponding to the persistent stable semiquinone radicals of solid samples of PM, and the formation of quinoid radicals in aqueous extracts of PM samples in air-saturated carbonate-buffered solution, pH 9.5-10.

scholarly journals High-performance inertial impaction filters for particulate matter removal

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaowei Zhang ◽  
Wei Zhang ◽  
Mingqiang Yi ◽  
Yingjie Wang ◽  
Pengjun Wang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
High Performance ◽  
Inertial Impaction

scholarly journals Hydrothermal characterization of wells GRT-1 and GRT-2 in Rittershoffen, France: Implications on the understanding of natural flow systems in the rhine graben

Geothermics ◽  
2017 ◽  
Vol 65 ◽  
pp. 255-268 ◽  
Author(s):  
C. Baujard ◽  
A. Genter ◽  
E. Dalmais ◽  
V. Maurer ◽  
R. Hehn ◽  
...  
Keyword(s):  
Rhine Graben ◽  
Natural Flow ◽  
Flow Systems
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