During the last decade constant improvements have been made in materials and structures design and control. But now some performance objectives cannot be achieved using classical technologies and require the use of the smart materials concept. But it is at the actuation end of the equation that smart materials and structures present the greatest challenge. It is here in particular that improved and even new materials have a leading role to play. Piezoelectrics, electrostrictives, photostrictives, magnetostrictives, electroactive polymers, shape memory materials, carbon nanotubes, rheological fluids,...all have their important contributions to make. So this paper aims to perform a brief review of the physical basis of the active materials behaviour.
{"title":"Comments on the physical basis of the active materials concept","authors":"P. Gobin, M. Salvia, L. David, M. Morin","doi":"10.1117/12.446780","DOIUrl":"https://doi.org/10.1117/12.446780","url":null,"abstract":"During the last decade constant improvements have been made in materials and structures design and control. But now some performance objectives cannot be achieved using classical technologies and require the use of the smart materials concept. But it is at the actuation end of the equation that smart materials and structures present the greatest challenge. It is here in particular that improved and even new materials have a leading role to play. Piezoelectrics, electrostrictives, photostrictives, magnetostrictives, electroactive polymers, shape memory materials, carbon nanotubes, rheological fluids,...all have their important contributions to make. So this paper aims to perform a brief review of the physical basis of the active materials behaviour.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114832971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Utilizing a general two-step procedure, a new class of porphodimethene macrocycles has been prepared, which can be easily converted to porphyrins bearing two 8-functionalized naphthalene spacers. Through straightforward modifications in the precursor molecules, macrocycles with a wide range of steric and electronic attributes can be isolated. With these simple ligands, metal-porphyrin complexes exhibiting interesting properties can be produced. For example, when two reactive groups are poised above the porphyrin, a reversible ring closure can take place under mild conditions, allowing for potential recognition sites close to a metal center to be electrochemically and chemically activated and deactivated. This intramolecular porphodimethene-porphyrin interconversion offers many exciting possibilities for the development of catalysis adept at specific transformations and for the design of novel sensors or photosensitizers.
{"title":"Porphodimethenes/porphyrins: redox-switchable tetrapyrrolic macrocycles","authors":"H. Gill, M. Harmjanz, M. J. Scott","doi":"10.1117/12.446774","DOIUrl":"https://doi.org/10.1117/12.446774","url":null,"abstract":"Utilizing a general two-step procedure, a new class of porphodimethene macrocycles has been prepared, which can be easily converted to porphyrins bearing two 8-functionalized naphthalene spacers. Through straightforward modifications in the precursor molecules, macrocycles with a wide range of steric and electronic attributes can be isolated. With these simple ligands, metal-porphyrin complexes exhibiting interesting properties can be produced. For example, when two reactive groups are poised above the porphyrin, a reversible ring closure can take place under mild conditions, allowing for potential recognition sites close to a metal center to be electrochemically and chemically activated and deactivated. This intramolecular porphodimethene-porphyrin interconversion offers many exciting possibilities for the development of catalysis adept at specific transformations and for the design of novel sensors or photosensitizers.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115382235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Complex Adaptive Structures can be viewed as a combination of Complex Adaptive Systems and fully integrated autonomous Smart Structures. Traditionally when designing a structure, one combines rules of thumb with theoretical results to develop an acceptable solution. This methodology will have to be extended for Complex Adaptive Structures, since they, by definition, will participate in their own design. In this paper we introduce a new methodology for Emergent System Identification that is concerned with combining the methodologies of self-organizing functional networks (GMDH - Alexy G. Ivakhnenko), Particle Swarm Optimization (PSO - James Kennedy and Russell C. Eberhart) and Genetic Programming (GP - John Koza). This paper will concentrate on the utilization of Particle Swarm Optimization in this effort and discuss how Particle Swarm Optimization relates to our ultimate goal of emergent self-organizing functional networks that can be used to identify overlapping internal structural models. The ability for Complex Adaptive Structures to identify emerging internal models will be a key component for their success.
复杂自适应结构可以看作是复杂自适应系统和完全集成的自主智能结构的结合。传统上，当设计一个结构时，人们将经验法则与理论结果结合起来，以开发一个可接受的解决方案。这种方法必须扩展到复杂自适应结构，因为根据定义，它们将参与自己的设计。本文介绍了一种结合自组织功能网络(GMDH - Alexy G. Ivakhnenko)、粒子群优化(PSO - James Kennedy和Russell C. Eberhart)和遗传规划(GP - John Koza)方法的紧急系统识别新方法。本文将集中讨论粒子群优化在这方面的应用，并讨论粒子群优化如何与我们的最终目标有关，即可用于识别重叠内部结构模型的紧急自组织功能网络。复杂自适应结构识别新兴内部模型的能力将是其成功的关键组成部分。
{"title":"Emergent system identification using particle swarm optimization","authors":"M. S. Voss, X. Feng","doi":"10.1117/12.446767","DOIUrl":"https://doi.org/10.1117/12.446767","url":null,"abstract":"Complex Adaptive Structures can be viewed as a combination of Complex Adaptive Systems and fully integrated autonomous Smart Structures. Traditionally when designing a structure, one combines rules of thumb with theoretical results to develop an acceptable solution. This methodology will have to be extended for Complex Adaptive Structures, since they, by definition, will participate in their own design. In this paper we introduce a new methodology for Emergent System Identification that is concerned with combining the methodologies of self-organizing functional networks (GMDH - Alexy G. Ivakhnenko), Particle Swarm Optimization (PSO - James Kennedy and Russell C. Eberhart) and Genetic Programming (GP - John Koza). This paper will concentrate on the utilization of Particle Swarm Optimization in this effort and discuss how Particle Swarm Optimization relates to our ultimate goal of emergent self-organizing functional networks that can be used to identify overlapping internal structural models. The ability for Complex Adaptive Structures to identify emerging internal models will be a key component for their success.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114303286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The design or architecture of bone is quite complex and diverse, ranging from a very porous cellular solid (trabecular bone) to a very dense solid (cortical bone). Significant adaptations to cortical and trabecular bone mass and architecture have been observed in response to changes in stresses acting on the tissue. The purpose of this paper is to examine bone stress-adaptation schemes, including so- called self-optimization theories of bone, within two- dimensional (2D) and three-dimensional (3D) finite element modeling (FEM) domains. Stress-adaptive FEM simulations are implemented using Matlab and involve analysis of stresses and strains, followed by successive iterations with the goal to globally minimize stress-strain objective functions (strain energy density, von Mises, maximum shear) without imposing constraints other than bounds on the relative density. Both isotropic and anisotropic material properties are considered while applying time-independent loading conditions for simple geometry domains with isoparametric elements. Application of a uniform tension/shear loading to 2D rectangular domains produced heterogeneous material, complex lattice structures that were qualitatively similar to trabecular bone. Three-dimensional cantilever beam analyses using isotropic and anisotropic material properties produced density-optimized, but not necessarily stiffness and strength optimized, structures. Finite element analysis simulations can assist in understanding complex adaptive structures, including bone.
{"title":"Finite element modeling of bone tissue stress adaptation","authors":"T. Keller","doi":"10.1117/12.446772","DOIUrl":"https://doi.org/10.1117/12.446772","url":null,"abstract":"The design or architecture of bone is quite complex and diverse, ranging from a very porous cellular solid (trabecular bone) to a very dense solid (cortical bone). Significant adaptations to cortical and trabecular bone mass and architecture have been observed in response to changes in stresses acting on the tissue. The purpose of this paper is to examine bone stress-adaptation schemes, including so- called self-optimization theories of bone, within two- dimensional (2D) and three-dimensional (3D) finite element modeling (FEM) domains. Stress-adaptive FEM simulations are implemented using Matlab and involve analysis of stresses and strains, followed by successive iterations with the goal to globally minimize stress-strain objective functions (strain energy density, von Mises, maximum shear) without imposing constraints other than bounds on the relative density. Both isotropic and anisotropic material properties are considered while applying time-independent loading conditions for simple geometry domains with isoparametric elements. Application of a uniform tension/shear loading to 2D rectangular domains produced heterogeneous material, complex lattice structures that were qualitatively similar to trabecular bone. Three-dimensional cantilever beam analyses using isotropic and anisotropic material properties produced density-optimized, but not necessarily stiffness and strength optimized, structures. Finite element analysis simulations can assist in understanding complex adaptive structures, including bone.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132116000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Newly developed evolutionary computational techniques have emerged as important tools for complex design tasks. In this paper, the basic concepts involved with artificial neural networks, fuzzy logic, the genetic algorithm and cellular automata will be presented. The origins of these techniques in natural complex adaptive systems will be identified, and a number of particular examples of the use of these techniques in practical applications will be discussed. Finally, the potential for the use of these techniques for the design of complex adaptive structures will be addressed.
{"title":"Evolutionary computational techniques for complex adaptive structures","authors":"W. Spillman","doi":"10.1117/12.446763","DOIUrl":"https://doi.org/10.1117/12.446763","url":null,"abstract":"Newly developed evolutionary computational techniques have emerged as important tools for complex design tasks. In this paper, the basic concepts involved with artificial neural networks, fuzzy logic, the genetic algorithm and cellular automata will be presented. The origins of these techniques in natural complex adaptive systems will be identified, and a number of particular examples of the use of these techniques in practical applications will be discussed. Finally, the potential for the use of these techniques for the design of complex adaptive structures will be addressed.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121912928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Star-shaped polymers containing poly(isobutyl methacrylate) (iBMA) and poly(tert-butyl methacrylate) (t-BMA) arms coupled to a 2,5-dimethyl-2,5-hexanediol dimethacrylate (DHDMA) core were synthesized using arm-first living anionic polymerization. Gel permeation chromatography (GPC) indicated that coupling efficiencies were high and coupled products exhibited a monomodal molecular weight distribution. The star-shaped polymer number--average molecular weights were 8-10 times higher than the precursor arm molecular weights. The ratio of coupling reagent to living chain end concentration controlled the molecular weight of the star-shaped polymer and the number of coupled arms. The molecular weight distributions of the star-shaped polymers ranged from 1.5-2.0. Due to the labile tertiary- butyl esters contained in the DHDMA cores, these star-shaped polymers were readily hydrolyzed in the presence of acid catalysts. For example, poly(iBMA) star-shaped polymers were hydrolytically stable at 25 degree(s)C and hydrolyzed readily at 65 degree(s)C in the presence of hydrochloric acid. In addition, the poly(t-BMA) containing star--shaped polymers degraded under similar conditions. The degradation process for the iBMA and t-BMA containing star-shaped polymers was confirmed using 1H NMR spectroscopy, and poly(iBMA)-block- poly(methacrylic acid) and poly(methacrylic acid) were obtained, respectively.
{"title":"Synthesis and characterization of novel acid-sensitive tert-butyl methacrylate and isobutyl methacrylate containing star-shaped polymers","authors":"T. Long, L. Kilian, Zhen-he Wang, A. Esker","doi":"10.1117/12.446778","DOIUrl":"https://doi.org/10.1117/12.446778","url":null,"abstract":"Star-shaped polymers containing poly(isobutyl methacrylate) (iBMA) and poly(tert-butyl methacrylate) (t-BMA) arms coupled to a 2,5-dimethyl-2,5-hexanediol dimethacrylate (DHDMA) core were synthesized using arm-first living anionic polymerization. Gel permeation chromatography (GPC) indicated that coupling efficiencies were high and coupled products exhibited a monomodal molecular weight distribution. The star-shaped polymer number--average molecular weights were 8-10 times higher than the precursor arm molecular weights. The ratio of coupling reagent to living chain end concentration controlled the molecular weight of the star-shaped polymer and the number of coupled arms. The molecular weight distributions of the star-shaped polymers ranged from 1.5-2.0. Due to the labile tertiary- butyl esters contained in the DHDMA cores, these star-shaped polymers were readily hydrolyzed in the presence of acid catalysts. For example, poly(iBMA) star-shaped polymers were hydrolytically stable at 25 degree(s)C and hydrolyzed readily at 65 degree(s)C in the presence of hydrochloric acid. In addition, the poly(t-BMA) containing star--shaped polymers degraded under similar conditions. The degradation process for the iBMA and t-BMA containing star-shaped polymers was confirmed using 1H NMR spectroscopy, and poly(iBMA)-block- poly(methacrylic acid) and poly(methacrylic acid) were obtained, respectively.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129291917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Swavey, Rodd Lee Williams, Z. Fang, M. Milkevitch, K. Brewer
The high binding affinity of cisplatin toward DNA has led to its popularity as an anticancer agent. Due to cumulative drug resistance and toxic side effects, researchers are exploring related metallodrugs. Our approach involves the use of supramolecular complexes. These mixed-metal complexes incorporate a reactive platinum moiety bridged by a polyazine ligand to a light absorbing metal-based chromophore. The presence of the light absorber allows excitation of these systems, opening up the possibility of photoactivation. The use of a supramolecular design allows components of the assembly to be varied to enhance device function and light absorbing properties. Aspects of our molecular design process and results on the DNA binding properties for a number of these mixed-metal complexes will be discussed.
{"title":"DNA binding of supramolecular mixed-metal complexes","authors":"S. Swavey, Rodd Lee Williams, Z. Fang, M. Milkevitch, K. Brewer","doi":"10.1117/12.446779","DOIUrl":"https://doi.org/10.1117/12.446779","url":null,"abstract":"The high binding affinity of cisplatin toward DNA has led to its popularity as an anticancer agent. Due to cumulative drug resistance and toxic side effects, researchers are exploring related metallodrugs. Our approach involves the use of supramolecular complexes. These mixed-metal complexes incorporate a reactive platinum moiety bridged by a polyazine ligand to a light absorbing metal-based chromophore. The presence of the light absorber allows excitation of these systems, opening up the possibility of photoactivation. The use of a supramolecular design allows components of the assembly to be varied to enhance device function and light absorbing properties. Aspects of our molecular design process and results on the DNA binding properties for a number of these mixed-metal complexes will be discussed.","PeriodicalId":341144,"journal":{"name":"Complex Adaptive Structures","volume":"4512 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129084523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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