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Dynamic Evolution (dynamic + evolution)
Selected AbstractsSoil detachment and transport on field- and laboratory-scale interrill areas: erosion processes and the size-selectivity of eroded sedimentEARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2006O. Malam Issa Abstract Field- and laboratory-scale rainfall simulation experiments were carried out in an investigation of the temporal variability of erosion processes on interrill areas, and the effects of such variation upon sediment size characteristics. Poorly aggregated sandy soils from the semi-arid environment of Senegal, West Africa, were used on both a 40 m2 field plot and a 0·25 m2 laboratory plot; rainfall intensity for all experiments was 70 mm h,1 with a duration of 1 to 2 hours. Time-series measurements were made of the quantity and the size distribution of eroded material: these permitted an estimate of the changing temporal balance between the main erosion processes (splash and wash). Results from both spatial scales showed a similar temporal pattern of runoff generation and sediment concentration. For both spatial scales, the dominant erosional process was detachment by raindrops; this resulted in a dynamic evolution of the soil surface under raindrop impact, with the rapid formation of a sieving crust followed by an erosion crust. However, a clear difference was observed between the two scales regarding the size of particles detached by both splash and wash. While all measured values were lower than the mean weight diameter (MWD) value of the original soil (mean 0·32 mm), demonstrating the size-selective nature of wash and splash processes, the MWD values of washed and splashed particles at the field scale ranged from 0·08 to 0·16 mm and from 0·12 to 0·30 mm respectively, whereas the MWD values of washed and splashed particles at the laboratory scale ranged from 0·13 to 0·29 mm and from 0·21 to 0·32 mm respectively. Thus only at the field scale were the soil particles detached by splash notably coarser than those transported by wash. This suggests a transport-limited erosion process at the field scale. Differences were also observed between the dynamics of the soil loss by wash at the two scales, since results showed wider scatter in the field compared to the laboratory experiments. This scatter is probably related to the change in soil surface characteristics due to the size-selectivity of the erosion processes at this spatial scale. Copyright © 2006 John Wiley & Sons, Ltd. [source] The Role of Political Instability in Stock Market Development and Economic Growth: The Case of GreeceECONOMIC NOTES, Issue 3 2000Dimitrios Asteriou This article examines empirically the relationship between stock market development, political instability and economic growth in Greece. We measure socio-political instability by constructing an index which captures the occurrence of various phenomena of political violence using time-series data. The main advantages of analysing political instability in a case study framework using time-series, in contrast with the widely used cross-country empirical studies, are: (a) a more careful and in-depth examination of institutional and historical characteristics of a particular country; (b) the use of a data set comprised of the most appropriate and highest quality measures; and (c) a more detailed exposition of the dynamic evolution of the economy. The empirical results indicate the existence of a strong negative relationship between uncertain socio-political conditions and the general index of the Athens Stock Exchange (ASE) and support the theoretical hypothesis that uncertain socio-political conditions affect economic growth negatively, is true for the Greek case. (J.E.L.: G10, G14, O40, C32) [source] Patchy distribution of flexible genetic elements in bacterial populations mediates robustness to environmental uncertaintyFEMS MICROBIOLOGY ECOLOGY, Issue 3 2008Holger Heuer Abstract The generation and maintenance of genetic variation seems to be a general ecological strategy of bacterial populations. Thereby they gain robustness to irregular environmental change, which is primarily the result of the dynamic evolution of biotic interactions. A benefit of maintaining population heterogeneity is that only a fraction of the population has to bear the cost of not (yet) beneficial deviation. On evolutionary time frames, an added value of the underlying mechanisms is evolvability, i.e. the heritable ability of an evolutionary lineage to generate and maintain genetic variants that are potentially adaptive in the course of evolution. Horizontal gene transfer is an important mechanism that can lead to differences between individuals within bacterial populations. Broad host-range plasmids foster this heterogeneity because they are typically present in only a fraction of the population and provide individual cells with genetic modules newly acquired from other populations or species. We postulate that the benefit of robustness on population level could balance the cost of transfer and replication functions that plasmids impose on their hosts. Consequently, mechanisms that make a subpopulation conducive to specific conjugative plasmids may have evolved, which could explain the persistence of even cryptic plasmids that do not encode any traits. [source] Defining hydrochemical evolution of streamflow through flowpath dynamics in Kawakami headwater catchment, Central JapanHYDROLOGICAL PROCESSES, Issue 10 2005Kasdi Subagyono Abstract The hydrochemical behaviour of catchments is often investigated by inferring stream chemistry through identification of source areas involved in hydrograph separation analysis, yet its dynamic evolution of hydrologic pathways has received little attention. Intensive hydrometric and hydrochemical measurements were performed during two different storms on March 29, 2001 and August 21,22, 2001 to define hydrochemical evolution under the dynamic of flow pathways in a 5·2 ha first-order drainage of the Kawakami experimental basin (KEB), Central Japan, a forested headwater catchment with various soil depths (1·8 to 5 m) overlying late Neogene of volcanic bedrocks. The hydraulic potential distribution and flow lines data showed that the change in flow direction, which was controlled by rainfall amount and antecedent wetness of the soil profile, agreed well with the hydrochemical change across the slope segment during the storm. Hydrograph separation predicted by end-member mixing analysis (EMMA) using Ca2+ and SiO2 showed that near surface riparian, hillslope soil water and deep riparian groundwater were important in stream flow generation. The evidence of decrease in solutes concentration at a depth of 1 m in the hillslope and 0·6 m in the near surface riparian during peak storm suggested a flushing of high solutes concentration. Most of the solutes accumulated in the deep riparian groundwater zone, which was due to prominent downward flow and agreed well with the residence time. The distinct flow pathways and chemistry between the near surface riparian and deep riparian groundwater zones and the linkage hillslope aquifer and near surface riparian reservoir, which controls rapid flow and solutes flushing during the storm event, are in conflict with the typical assumption that the whole riparian zone resets flow pathways and chemical signature of hillslope soil water, as has been reported in a previous study. Copyright © 2005 John Wiley & Sons, Ltd. [source] Critical evaluation of CFD codes for interfacial simulation of bubble-train flow in a narrow channelINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 6 2007Furkan Özkan Abstract Computational fluid dynamics (CFD) codes that are able to describe in detail the dynamic evolution of the deformable interface in gas,liquid or liquid,liquid flows may be a valuable tool to explore the potential of multi-fluid flow in narrow channels for process intensification. In the present paper, a computational exercise for co-current bubble-train flow in a square vertical mini-channel is performed to investigate the performance of well-known CFD codes for this type of flows. The computations are based on the volume-of-fluid method (VOF) where the transport equation for the liquid volumetric fraction is solved either by the methods involving a geometrical reconstruction of the interface or by the methods that use higher-order difference schemes instead. The codes contributing to the present code-to-code comparison are an in-house code and the commercial CFD packages CFX, FLUENT and STAR-CD. Results are presented for two basic cases. In the first one, the flow is driven by buoyancy only, while in the second case the flow is additionally forced by an external pressure gradient. The results of the code-to-code comparison show that only the VOF method with interface reconstruction leads to physically sound and consistent results, whereas the use of difference schemes for the volume fraction equation shows some deficiencies. Copyright © 2007 John Wiley & Sons, Ltd. [source] Morphological population balance model in principal component spaceAICHE JOURNAL, Issue 9 2009Xue Z. Wang Abstract Multidimensional and morphological population balance (PB) models for crystallization processes have been proposed in literature, which can be used to simulate the dynamic evolution of particle shape as well as particle size distribution. These models, however, can become computationally expensive when the crystal has a large number of independent faces, and are not applicable to noncrystalline, irregularly shaped particles such as those encountered in granulation and milling. This article addresses these challenges by introducing principal component analysis (PCA) into morphological PB modeling. PCA transforms the shape description of a particle from a high-dimensional domain to a lower dimensional, principal component (PC) space. Morphological PB models can then be built in this latent variable space, greatly reducing the computational complexity. It also makes it possible to model noncrystalline irregularly shaped particles. The original particle shape at any time can be reconstructed from the PCs. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Particle shape manipulation and optimization in cooling crystallization involving multiple crystal morphological formsAICHE JOURNAL, Issue 8 2009Jian Wan Abstract A population balance model for predicting the dynamic evolution of crystal shape distribution is further developed to simulate crystallization processes in which multiple crystal morphological forms co-exist and transitions between them can take place. The new model is applied to derive the optimal temperature and supersaturation profiles leading to the desired crystal shape distribution in cooling crystallization. Since tracking an optimum temperature or supersaturation trajectory can be easily implemented by manipulating the coolant flowrate in the reactor jacket, the proposed methodology provides a feasible closed-loop mechanism for crystal shape tailoring and control. The methodology is demonstrated by applying it to a case study of seeded cooling crystallization of potash alum. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Polymetamorphism, zircon growth and retention of early assemblages through the dynamic evolution of a continental arc in Fiordland, New ZealandJOURNAL OF METAMORPHIC GEOLOGY, Issue 4 2009J. M. SCOTT Abstract The Marguerite Amphibolite and associated rocks in northern Fiordland, New Zealand, contain evidence for retention of Carboniferous metamorphic assemblages through Cretaceous collision of an arc, emplacement of large volumes of mafic magma, high- P metamorphism and then extensional exhumation. The amphibolite occurs as five dismembered aluminous meta-gabbroic xenoliths up to 2 km wide that are enclosed within meta-leucotonalite of the Lake Hankinson Complex. A first metamorphic event (M1) is manifest in the amphibolite as a pervasively lineated pargasite,anorthite,kyanite or corundum ± rutile assemblage, and as diffusion-zoned garnet in pelitic schist xenoliths within the amphibolite. Thin zones of metasomatically Al-enriched leucotonalite directly at the margins of each amphibolite xenolith indicate element redistribution during M1 and equilibration at 6.6 ± 0.8 kbar and 618 ± 25 °C. A second phase of recrystallization (M2) formed patchy and static margarite ± kyanite,staurolite,chlorite,plagioclase,epidote assemblages in the amphibolite, pseudomorphs of coronas in gabbronorite, and thin high-grossular garnet rims in the pelitic schists. Conditions of M2, 8.8 ± 0.6 kbar and 643 ± 27 °C, are recorded from the rims of garnet in the pelitic schists. Cathodoluminescence imaging and simultaneous acquisition of U-Th-Pb isotopes and trace elements by depth-profiling zircon grains from one pelitic schist reveals four stages of growth, two of which are metamorphic. The first metamorphic stage, dated as 340.2 ± 2.2 Ma, is correlated with M1 on the basis that the unusual zircon trace element compositions indicate growth from a metasomatic fluid derived from the surrounding amphibolite during penetrative deformation. A second phase of zircon overgrowth coupled with crosscutting relationships date M2 to between 119 and 117 Ma. The Early Carboniferous event has not previously been recognized in northern Fiordland, whereas the latter event, which has been identified in Early Cretaceous batholiths, their xenoliths, and rocks directly at batholith margins, is here shown to have also affected the country rock. However, the effects of M2 are fragmentary due to limited element mobility, lack of deformation, distance from a heat source and short residence time in the lower crust during peak P and T. It is possible that many parts of the Fiordland continental arc achieved high- P conditions in the Early Cretaceous but retain earlier metamorphic or igneous assemblages. [source] A counter-clockwise P,T path for the Voltri Massif eclogites (Ligurian Alps, Italy)JOURNAL OF METAMORPHIC GEOLOGY, Issue 7 2005G. VIGNAROLI Abstract Integrated petrological and structural investigations of eclogites from the eclogite zone of the Voltri Massif (Ligurian Alps) have been used to reconstruct a complete Alpine P,T deformation path from burial by subduction to subsequent exhumation. The early metamorphic evolution of the eclogites has been unravelled by correlating garnet zonation trends with the chemical variations in inclusions found in the different garnet domains. Garnet in massive eclogites displays typical growth zoning, whereas garnet in foliated eclogites shows rim-ward resorption, likely related to re-equilibration during retrogressive evolution. Garnet inclusions are distinctly different from core to rim, consisting primarily of Ca-, Na/Ca-amphibole, epidote, paragonite and talc in garnet cores and of clinopyroxene ± talc in the outer garnet domains. Quantitative thermobarometry on the inclusion assemblages in the garnet cores defines an initial greenschist-to-amphibolite facies metamorphic stage (M1 stage) at c. 450,500 °C and 5,8 kbar. Coexistence of omphacite + talc + katophorite inclusion assemblage in the outer garnet domains indicate c. 550 °C and 20 kbar, conditions which were considered as minimum P,T estimates for the M2 eclogitic stage. The early phase of retrograde reactions is polyphase and equilibrated under epidote,blueschist facies (M3 stage), characterized by the development of composite reaction textures (garnet necklaces and fluid-assisted Na-amphibole-bearing symplectites) produced at the expense of the primary M2 garnet-clinopyroxene assemblage. The blueschist retrogression is contemporaneous with the development of a penetrative deformation (D3) that resulted in a non-coaxial fabric, with dominant top-to-the-N sense of shear during rock exhumation. All of that is overprinted by a texturally late amphibolite/greenschist facies assemblages (M4 & M5 stages), which are not associated with a penetrative structural fabric. The combined P,T deformation data are consistent with an overall counter-clockwise path, from the greenschist/amphibolite, through the eclogite, the blueschist to the greenschist facies. These new results provide insights into the dynamic evolution of the Tertiary oceanic subduction processes leading to the building up of the Alpine orogen and the mechanisms involved in the exhumation of its high-pressure roots. [source] Crystal growth rate dispersion modeling using morphological population balanceAICHE JOURNAL, Issue 9 2008Cai Y. Ma Abstract Crystal growth in solution is a surface-controlled process. The variation of growth rates of different crystal faces is considered to be due to the molecular arrangement in the crystal unit cell as well as the crystal surface structures of different faces. As a result, for some crystals, the growth rate for a specific facet is not only a function of supersaturation, but also dependent on some other factors such as its size and the lattice spread angle. This phenomenon of growth rate dispersion (GRD) or fluctuation has been described in literature to have attributed to the formation of some interesting and sophisticated crystal structures observed in experimental studies. In this article, GRD is introduced to a recently proposed morphological population balance model to simulate the dynamic evolution of crystal size distribution in each face direction for the crystallization of potash alum, a chemical that has been reported to show GRD phenomenon and sophisticated crystal structures. The GRD is modeled as a function of the effective relative supersaturation, which is directly related to crystal size, lattice spread angle, relative supersaturation, and solution temperature. The predicted results clearly demonstrated the significant effect of GRD on the shape evolution of the crystals. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] In Situ X-Ray Radiography and Tomography Observations of the Solidification of Aqueous Alumina Particle Suspensions,Part I: Initial InstantsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2009Sylvain Deville This paper investigates by in situ high-resolution X-ray radiography and tomography the behavior of colloidal suspensions of alumina partic les during directional solidification by freezing. The combination of these techniques provided both qualitative and quantitative information about the propagation kinetic of the solid/liquid interface, the particle redistribution between the crystals and a particle-enriched phase, and the three-dimensional organization of the ice crystals. In this first part of two companion papers, the precursor phenomena leading to directional crystallization during the first instants of solidification are studied. Mullins,Sekerka instabilities are not necessary to explain the dynamic evolution of the interface pattern. Particle redistribution during these first instants is dependent on the type of crystals growing into the suspension. The insights gained into the mechanisms of solidification of colloidal suspensions may be valuable for the materials processing routes derived for this type of directional solidification (freeze-casting), and of general interest for those interested in the interactions between solidification fronts and inert particles. [source] Prediction of Chain Length Distribution of Polystyrene Made in Batch Reactors with Bifunctional Free-Radical Initiators Using Dynamic Monte Carlo SimulationMACROMOLECULAR REACTION ENGINEERING, Issue 3 2007Ibrahim M. Maafa Abstract The objective of this paper is to present a dynamic Monte Carlo model that is able to simulate the polymerization of styrene with bifunctional free-radical initiators in a batch reactor. The model can predict the dynamic evolution of the chain length distribution of polystyrene in the reactor. The model includes all relevant polymerization mechanistic steps, including chemical and thermal radical generation, and diffusion-controlled termination. The model was applied to styrene polymerization and the Monte Carlo estimates for chain length averages were compared to those obtained with the method of moments. Excellent agreement was obtained between the two methods. Although styrene polymerization was used as a case study, the proposed methodology can be easily extended to any other polymer type made by free-radical polymerization. [source] Particulate Matter in the Ross Sea: a Spreading ModelMARINE ECOLOGY, Issue 2002Sergio Tucci Abstract. Within the framework of the C.L.I.M.A. Project, a part of the Italian Research Program in Antarctica, the Total Particulate Matter (TPM) was used as a natural marker to characterise the water masses. The dynamics of TPM was estimated by using a numerical model capable of following the evolution of the basin during the ice absence in summer. The first numerical simulation, with horizontally constant initial conditions and the absence of TPM source areas, merely reveals how TPM passive dispersion is strongly influenced by the Ross Ice Shelf and bathymetry. The second simulation, with TPM concentration horizontally variable and vertically decreasing layers, shows a dynamic evolution of TPM that is in agreement with experimental data. On the surface, in correspondence with the shelf-break, an out-flowing flux with particulate matter contribution coming from Ross Ice Shelf is recognised. The TPM concentration may be linked to the ice melting due to the Antarctic Surface Water, with production of Shallow Ice Shelf Water. The numerical model produces, near the Drygalski area, two cells with high concentration. This numerical evolution is confirmed by the 1990 data (Spezie et al, 1993) that clearly show these two areas and their correlations with the Drygalski contributions (the inner area) and with the thermo-haline front (the external one). This condition is evident in the 1994-1995 data too (Bu-dillon et al, 1999). In this case the authors observed that the Circumpolar Deep Water penetrates onto the shelf at about 174°E; then, modifying its properties, it follows a southward path for about 200 km. The Antarctic Shelf Front (ASF) separates CDW from the colder shelf water with a high concentration of suspended matter. At the 300-meter level, the diffusion of the particulate matter directed under the RIS, towards the continental shelf, seems to be an important feature. Very high TPM values are also present in the deep water in the area off the Drygalski Glacier; this evolution agrees with the ,400 m data collected during the 1990,1991 cruise (Spezie et al., 1993). [source] Proteomics enhances evolutionary and functional analysis of reproductive proteinsBIOESSAYS, Issue 1 2010Geoffrey D. Findlay Reproductive proteins maintain species-specific barriers to fertilization, affect the outcome of sperm competition, mediate reproductive conflicts between the sexes, and potentially contribute to the formation of new species. However, the specific proteins and molecular mechanisms that underlie these processes are understood in only a handful of cases. Advances in genomic and proteomic technologies enable the identification of large suites of reproductive proteins, making it possible to dissect reproductive phenotypes at the molecular level. We first review these technological advances and describe how reproductive proteins are identified in diverse animal taxa. We then discuss the dynamic evolution of reproductive proteins and the potential selective forces that act on them. Finally, we describe molecular and genomic tools for functional analysis and detail how evolutionary data may be used to make predictions about interactions among reproductive proteins. [source] Dynamics of bacterial growth and distribution within the liver during Salmonella infectionCELLULAR MICROBIOLOGY, Issue 9 2003Mark Sheppard Summary Salmonella enterica causes severe systemic diseases in humans and animals and grows intracellularly within discrete tissue foci that become pathological lesions. Because of its lifestyle Salmonella is a superb model for studying the in vivo dynamics of bacterial distribution. Using multicolour fluorescence microscopy in the mouse typhoid model we have studied the interaction between different bacterial populations in the same host as well as the dynamic evolution of foci of infection in relation to bacterial growth and localization. We showed that the growth of Salmonella in the liver results in the spread of the microorganisms to new foci of infection rather than simply in the expansion of the initial ones. These foci were associated with independently segregating bacterial populations and with low numbers of bacteria in each infected phagocyte. Using fast-growing and slow-growing bacteria we also showed that the increase in the number of infected phagocytes parallels the net rate of bacterial growth of the microorganisms in the tissues These findings suggest a novel mechanism underlying growth of salmonellae in vivo with important consequences for understanding mechanisms of resistance and immunity. [source] A Time-Resolved Spectroscopic Study of the Bichromophoric Phototrigger 3,,5,-Dimethoxybenzoin Diethyl Phosphate: Interaction Between the Two Chromophores Determines the Reaction PathwayCHEMISTRY - A EUROPEAN JOURNAL, Issue 17 2010Chensheng Ma Dr. Abstract 3,,5,-Dimethoxybenzoin (DMB) is a bichromophoric system that has widespread application as a highly efficient photoremovable protecting group (PRPG) for the release of diverse functional groups. The photodeprotection of DMB phototriggers is remarkably clean, and is accompanied by the formation of a biologically benign cyclization product, 3,,5,-dimethoxybenzofuran (DMBF). The underlying mechanism of the DMB deprotection and cyclization has, however, until now remained unclear. Femtosecond transient absorption (fs-TA) spectroscopy and nanosecond time-resolved resonance Raman (ns-TR3) spectroscopy were employed to detect the transient species directly, and examine the dynamic transformations involved in the primary photoreactions for DMB diethyl phosphate (DMBDP) in acetonitrile (CH3CN). To assess the electronic character and the role played by the individual sub-chromophore, that is, the benzoyl, and the di- meta -methoxybenzylic moieties, for the DMBDP deprotection, comparative fs-TA measurements were also carried out for the reference compounds diethyl phosphate acetophenone (DPAP), and 3,,5,-dimethoxybenzylic diethyl phosphate (DMBnDP) in the same solvent. Comparison of the fs-TA spectra reveals that the photoexcited DMBDP exhibits distinctly different spectral character and dynamic evolution from those of the reference compounds. This fact, combined with the related steady-state spectral and density functional theoretical results, strongly suggests the presence in DMBDP of a significant interaction between the two sub-chromophores, and that this interaction plays a governing role in determining the nature of the photoexcitation and the reaction channel of the subsequent photophysical and photochemical transformations. The ns-TR3 results and their correlation with the fs-TA spectra and dynamics provide evidence for a novel concerted deprotection,cyclization mechanism for DMBDP in CH3CN. By monitoring the direct generation of the transient DMBF product, the cyclization time constant was determined unequivocally to be ,1,ns. This indicates that there is little relevance for the long-lived intermediates (>10,ns) in giving the DMBF product, and excludes the stepwise mechanism proposed in the literature as the major pathway for the DMB cyclization reaction. This work provides important new insights into the origin of the 3,,5,-dimethoxy substitution effect for the DMB photodeprotection. It also helps to clarify the many different views presented in previous mechanistic studies of the DMB PRPGs. In addition to this, our fs-TA results on the reference compound DMBnDP in CH3CN provide the first direct observation (to the best of our knowledge) showing the predominance of a prompt (,2,ps) heterolytic bond cleavage after photoexcitation of meta -methoxybenzylic compounds. This provides insight into the long-term controversies about the photoinitiated dissociation mode of related substituted benzylic compounds. [source] Dynamic colonisation by different Pneumocystis jirovecii genotypes in cystic fibrosis patientsCLINICAL MICROBIOLOGY AND INFECTION, Issue 10 2007M. A. Montes-Cano Abstract Although asymptomatic carriers of Pneumocystis jirovecii with cystic fibrosis (CF) have been described previously, the molecular epidemiology of P. jirovecii in CF patients has not yet been clarified. This study identified the distribution and dynamic evolution of P. jirovecii genotypes based on the mitochondrial large-subunit (mt LSU) rRNA gene. The mt LSU rRNA genotypes of P. jirovecii isolates in 33 respiratory samples from CF patients were investigated using nested PCR and direct sequencing. Three different genotypes were detected: 36.3% genotype 1 (85C/248C); 15.1% genotype 2 (85A/248C); 42.4% genotype 3 (85T/248C); and 6% mixed genotypes. Patients studied during a 1-year follow-up period showed a continuous colonisation/clearance cycle involving P. jirovecii and an accumulative tendency to be colonised with genotype 3. [source] A design-variable-based inelastic hysteretic model for beam,column connectionsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2008Gun Jin Yun Abstract This paper presents a design-variable-based inelastic hysteretic model for beam,column connections. It has been well known that the load-carrying capacity of connections heavily depends on the types and design variables even in the same connection type. Although many hysteretic connection models have been proposed, most of them are dependent on the specific connection type with presumed failure mechanisms. The proposed model can be responsive to variations both in design choices and in loading conditions. The proposed model consists of two modules: physical-principle-based module and neural network (NN)-based module in which information flow from design space to response space is formulated in one complete model. Moreover, owing to robust learning capability of a new NN-based module, the model can also learn complex dynamic evolutions in response space under earthquake loading conditions, such as yielding, post-buckling and tearing, etc. Performance of the proposed model has been demonstrated with synthetic and experimental data of two connection types: extended-end-plate and top- and seat-angle with double-web-angle connection. Furthermore, the design-variable-based model can be customized to any structural component beyond the application to beam,column connections. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||