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Sample records for structures model experimental

  1. Models, simulation, and experimental issues in structural mechanics

    CERN Document Server

    Maceri, Franco; Vairo, Giuseppe

    2017-01-01

    The reader aware in Structural Mechanics will find in this book a source of fruitful knowledge and effective tools useful for imagining, creating, and promoting novel and challenging developments. It addresses a wide range of topics, such as mechanics and geotechnics, vibration and damping, damage and friction, experimental methods, and advanced structural materials. It also discusses analytical, experimental and numerical findings, focusing on theoretical and practical issues, and leading to innovations in the field. Collecting some of the latest results from the Lagrange Laboratory, a European scientific research group, mainly consisting of Italian and French engineers, mechanicians and mathematicians, the book presents the most recent example of the long-term scientific cooperation between well-established French and Italian Mechanics, Mathematics and Engineering Schools. .

  2. Theoretical temperature model with experimental validation for CLIC Accelerating Structures

    CERN Document Server

    AUTHOR|(CDS)2126138; Vamvakas, Alex; Alme, Johan

    Micron level stability of the Compact Linear Collider (CLIC) components is one of the main requirements to meet the luminosity goal for the future $48 \\,km$ long underground linear accelerator. The radio frequency (RF) power used for beam acceleration causes heat generation within the aligned structures, resulting in mechanical movements and structural deformations. A dedicated control of the air- and water- cooling system in the tunnel is therefore crucial to improve alignment accuracy. This thesis investigates the thermo-mechanical behavior of the CLIC Accelerating Structure (AS). In CLIC, the AS must be aligned to a precision of $10\\,\\mu m$. The thesis shows that a relatively simple theoretical model can be used within reasonable accuracy to predict the temperature response of an AS as a function of the applied RF power. During failure scenarios or maintenance interventions, the RF power is turned off resulting in no heat dissipation and decrease in the overall temperature of the components. The theoretica...

  3. Modeling the Structure of Helical Assemblies with Experimental Constraints in Rosetta.

    Science.gov (United States)

    André, Ingemar

    2018-01-01

    Determining high-resolution structures of proteins with helical symmetry can be challenging due to limitations in experimental data. In such instances, structure-based protein simulations driven by experimental data can provide a valuable approach for building models of helical assemblies. This chapter describes how the Rosetta macromolecular package can be used to model homomeric protein assemblies with helical symmetry in a range of modeling scenarios including energy refinement, symmetrical docking, comparative modeling, and de novo structure prediction. Data-guided structure modeling of helical assemblies with experimental information from electron density, X-ray fiber diffraction, solid-state NMR, and chemical cross-linking mass spectrometry is also described.

  4. Validating a Finite Element Model of a Structure Subjected to Mine Blast with Experimental Modal Analysis

    Science.gov (United States)

    2017-11-01

    FE finite element MAC modal assurance criteria SAE Society of Automotive Engineers SDIC stereo-digital image correlation SLAD Survivability...ARL-TR-8224 ● NOV 2017 US Army Research Laboratory Validating a Finite Element Model of a Structure Subjected to Mine Blast with...NOV 2017 US Army Research Laboratory Validating a Finite Element Model of a Structure Subjected to Mine Blast with Experimental Modal

  5. Matching experimental and three dimensional numerical models for structural vibration problems with uncertainties

    Science.gov (United States)

    Langer, P.; Sepahvand, K.; Guist, C.; Bär, J.; Peplow, A.; Marburg, S.

    2018-03-01

    The simulation model which examines the dynamic behavior of real structures needs to address the impact of uncertainty in both geometry and material parameters. This article investigates three-dimensional finite element models for structural dynamics problems with respect to both model and parameter uncertainties. The parameter uncertainties are determined via laboratory measurements on several beam-like samples. The parameters are then considered as random variables to the finite element model for exploring the uncertainty effects on the quality of the model outputs, i.e. natural frequencies. The accuracy of the output predictions from the model is compared with the experimental results. To this end, the non-contact experimental modal analysis is conducted to identify the natural frequency of the samples. The results show a good agreement compared with experimental data. Furthermore, it is demonstrated that geometrical uncertainties have more influence on the natural frequencies compared to material parameters and material uncertainties are about two times higher than geometrical uncertainties. This gives valuable insights for improving the finite element model due to various parameter ranges required in a modeling process involving uncertainty.

  6. Experimental measurements of subsoil–structure interaction and 3D numerical models

    Directory of Open Access Journals (Sweden)

    Jana Labudkova

    2016-03-01

    Full Text Available Use of combination of experimental measurements, tests in situ and numerical modelling is optimal approach to obtain reliable results of subsoil–structure interaction. Input data for numerical analyses were obtained by experimental loading tests of three different types of concrete slabs. Loading was performed out using experimental equipment. The unique experimental equipment was constructed in the area of Faculty of Civil Engineering, VŠB-TU Ostrava. Analyses of interaction of reinforced concrete slabs with subsoil were solved by application of inhomogeneous half-space. The main focus was to verify the aptness of application of inhomogeneous half-space in relation to the slab deformations in comparison of different types of reinforcements of concrete slab.

  7. Experimental Studies on Finite Element Model Updating for a Heated Beam-Like Structure

    Directory of Open Access Journals (Sweden)

    Kaipeng Sun

    2015-01-01

    Full Text Available An experimental study was made for the identification procedure of time-varying modal parameters and the finite element model updating technique of a beam-like thermal structure in both steady and unsteady high temperature environments. An improved time-varying autoregressive method was proposed first to extract the instantaneous natural frequencies of the structure in the unsteady high temperature environment. Based on the identified modal parameters, then, a finite element model for the structure was updated by using Kriging meta-model and optimization-based finite-element model updating method. The temperature-dependent parameters to be updated were expressed as low-order polynomials of temperature increase, and the finite element model updating problem was solved by updating several coefficients of the polynomials. The experimental results demonstrated the effectiveness of the time-varying modal parameter identification method and showed that the instantaneous natural frequencies of the updated model well tracked the trends of the measured values with high accuracy.

  8. Spectroscopic evaluation of painted layer structural changes induced by gamma radiation in experimental models

    International Nuclear Information System (INIS)

    Manea, Mihaela M.; Moise, Ioan V.; Virgolici, Marian; Negut, Constantin D.; Barbu, Olimpia-Hinamatsuri; Cutrubinis, Mihalis; Fugaru, Viorel; Stanculescu, Ioana R.; Ponta, Corneliu C.

    2012-01-01

    The degradation of cultural heritage objects by insects and microorganisms is an important issue for conservators, art specialists and humankind in general. Gamma irradiation is an efficient method of polychrome wooden artifacts disinfestation. Color changes and other modifications in the physical chemical properties of materials induced by gamma irradiation are feared by cultural heritage responsible committees and they have to be evaluated objectively and precisely. In this paper FTIR and FT-Raman spectroscopy methods were used to investigate the structural changes in some experimental models of tempera paint layers on wood following 11 kGy gamma irradiation at two dose rates. Radiation chemistry depends on the particular pigment, matrix formed by protein, resin (in case of varnished samples) and water presence. For the majority of painted layer in experimental models very small spectral variations were observed. Small changes in the FTIR spectra were observed for the raw sienna experimental model: for the higher dose rate the egg yolk protein oxidation peaks and the CH stretching bands due to lipids degradation products increased. - Highlights: ► Experimental models of tempera paint layers on wood were γ-irradiated at two dose rates. ► Changes induced by γ-irradiation were evaluated by vibrational spectroscopy. ► Minor spectral variations of painted layer were observed. ► Raw sienna FTIR spectra showed little changes of egg yolk and lipids at higher dose rate. ► Gamma irradiation is recommended for disinfection of painted wooden artifacts.

  9. Developmental models for estimating ecological responses to environmental variability: structural, parametric, and experimental issues.

    Science.gov (United States)

    Moore, Julia L; Remais, Justin V

    2014-03-01

    Developmental models that account for the metabolic effect of temperature variability on poikilotherms, such as degree-day models, have been widely used to study organism emergence, range and development, particularly in agricultural and vector-borne disease contexts. Though simple and easy to use, structural and parametric issues can influence the outputs of such models, often substantially. Because the underlying assumptions and limitations of these models have rarely been considered, this paper reviews the structural, parametric, and experimental issues that arise when using degree-day models, including the implications of particular structural or parametric choices, as well as assumptions that underlie commonly used models. Linear and non-linear developmental functions are compared, as are common methods used to incorporate temperature thresholds and calculate daily degree-days. Substantial differences in predicted emergence time arose when using linear versus non-linear developmental functions to model the emergence time in a model organism. The optimal method for calculating degree-days depends upon where key temperature threshold parameters fall relative to the daily minimum and maximum temperatures, as well as the shape of the daily temperature curve. No method is shown to be universally superior, though one commonly used method, the daily average method, consistently provides accurate results. The sensitivity of model projections to these methodological issues highlights the need to make structural and parametric selections based on a careful consideration of the specific biological response of the organism under study, and the specific temperature conditions of the geographic regions of interest. When degree-day model limitations are considered and model assumptions met, the models can be a powerful tool for studying temperature-dependent development.

  10. Soil gas and radon entry into a simple test structure: Comparison of experimental and modelling results

    DEFF Research Database (Denmark)

    Andersen, C.E.; Søgaard-Hansen, J.; Majborn, B.

    1994-01-01

    A radon test structure has been established at a field site at Riso National Laboratory. Measurements have been made of soil gas entry rates, pressure couplings and radon depletion. The experimental results have been compared with results obtained from measured soil parameters and a two......-dimensional steady-state numerical model of Darcy flow and combined diffusive and advective transport of radon. For most probe locations, the calculated values of the pressure couplings and the radon depletion agree well with the measured values, thus verifying important elements of the Darcy flow approximation......, and the ability of the model to treat combined diffusive and advective transport of radon. However, the model gives an underestimation of the soil gas entry rate. Even if it is assumed that the soil has a permeability equal to the highest of the measured values, the model underestimates the soil gas entry rate...

  11. Combustion chemistry of alcohols: Experimental and modeled structure of a premixed 2-methylbutanol flame

    KAUST Repository

    Lucassen, Arnas

    2014-06-14

    This paper presents a detailed investigation of 2-methylbutanol combustion chemistry in low-pressure premixed flames. This chemistry is of particular interest to study because this compound is potentially a lignocellulosic-based, next-generation biofuel. The detailed chemical structure of a stoichiometric low-pressure (25 Torr) flame was determined using flame-sampling molecular-beam mass spectrometry. A total of 55 species were identified and subsequently quantitative mole fraction profiles as function of distance from the burner surface were determined. In an independent effort, a detailed flame chemistry model for 2-methylbutanol was assembled based on recent knowledge gained from combustion chemistry studies for butanol isomers ([Sarathy et al. Combust. Flame 159 (6) (2012) 2028-2055]) and iso-pentanol (3-methylbutanol) [Sarathy et al. Combust. Flame 160 (12) (2013) 2712-2728]. Experimentally determined and modeled mole fraction profiles were compared to demonstrate the model\\'s capabilities. Examples of individual mole fraction profiles are discussed together with the most significant fuel consumption pathways to highlight the combustion chemistry of 2-methylbutanol. Discrepancies between experimental and modeling results are used to suggest areas where improvement of the kinetic model would be needed. © 2014.

  12. Experimental vibration analysis for a 3D scaled model of a three-floor steel structure

    Directory of Open Access Journals (Sweden)

    Ernesto F. Castillo

    Full Text Available In this paper we present an experimental study of a three dimensional physical model of a three-floor structure subjected to forced vibrations by imposing displacements in its support. The aim of this work is to analyze the behavior of the building when a dynamic vibration absorber (DVA is acting. An analytic simplified analysis and a numerical study are developed to obtain the natural frequencies of the structure. Experiments are carried out in a vibrating table. The frequency range to be experimentally analyzed is determined by the first natural frequency of the structure for which the DVA damping effects are verified. The equipment capabilities, i.e. the frequencies, amplitudes and admissible load, limit the analyses. Nevertheless, satisfactory results are obtained for the study of the first mode of vibration. The effect of different amplitudes of the imposed support motion is also analyzed. In addition, the damping effect of the DVA device is evaluated upon varying its mass and its location in the structure. The characteristic curves in the frequency domain are obtained computing the Fast Fourier Transformation (FFT of the acceleration history registered with piezoelectric accelerometers at different checkpoints for the cases analyzed.

  13. The social structure of ''experimental'' strings at Fermilab; a physics and detector driven model

    International Nuclear Information System (INIS)

    Bodnarczuk, M.

    1990-01-01

    Physicists in HEP have been forced to organize large scientific projects without a well defined organizational or sociological model to guide them. In the absence of such models, what structures do experimentalists use to develop social structures in HEP? In this paper, I claim that physicists organize around what they know best, the physics problems they study and the detectors and devices they study them with. After describing the advent of ''management'' in HEP, I use a case study of 4 Fermilab experiments as the base upon which to propose a physics and detector driven model of social structure for experiments. In addition, I show how this model can be extended to describe ''strings'' of experiments, where continuities of physics interests, spectrometer design, and a core group of physicists become a definable sociological unit that can exist for over 15 years. A dominate theme that emerges from my analysis is the conscious attempt on the part of experimenters to remove the uncertainties that are part of the practice of HEP

  14. An experimental work on wireless structural health monitoring system applying on a submarine model scale

    Science.gov (United States)

    Nugroho, W. H.; Purnomo, N. J. H.; Soedarto, T.

    2016-11-01

    This paper presents an experimental work to monitor the health of submarine hull structures using strain sensors and wireless communication technology. The monitored - submarine hull was built in a hydro elastic model scale 1: 30 with a steel bar backbone and tested on water tank of Indonesian Hydrodynamic Laboratory (IHL). Specifically, this health monitoring system for the submarine model was developed using wireless modems, data communication software and conventional strain sensors. This system was used to monitor the loads on a steel bar backbone of the running submarine model from the edge of the water tank. Commands were issued from a notebook to instruct the health monitoring system to acquire data from sensors mounted externally to the steel bar. Data from measurements made on the structure are then transmitted wirelessly back to a notebook computer for processing and analysis. The results of the tank test have been validated and showed no loss of communication signal over an area of the tank. This work also presents a potential use of involving complete automation of this system with an in-service structure coupled with an on-line warning/damage detection capability.

  15. Experimental support and estimate of the accuracy of the water flow model in structured soils

    Science.gov (United States)

    Nikulina, M.

    2003-04-01

    The set of models of water flow and solute transport was developed. It takes into account spatial and time variability of soil properties and a complex structure of a soil pore space. However, its limited by physically justified methods of experimental definition of parameters. The important stage of the work with the models is checking their adequacy to described processes. It is possible only at a presence of the qualitative experi-mental data received under conditions, reproduced by model. According to this, the aim of the work is the support of methods of experimental maintenance of water flow models with taking into account of structure of soil porosity and evaluation of conditions of application of mathematical models of a dif-ferent level. The field experiments were conducted in Suzdal (Russia, Vladimirskaja oblast), in June and July 1997. The soil cover of this region has high complexity, in which grey forest soils are dominant. Genetic horizons of the grey forest soils are well structured, this causes the presence in soil profile the macropores. The field investigation consisted of three big parts: (1) the morphological research of the genetic horizons of the grey forest soil; (2) investigation of the soil filtration properties by the tube with a constant head and vacuum-infiltrometer methods; (3) study of water movement at different intensity of the irrigation. Experiments were conducted on three sets called , and . The plots had 1m x 1m a size and were equipped with the hole for measurement of soil water content by the neutron hygrometer and by the tensiometers. In labo-ratory conditions the following properties of soil were determined: density of soil, texture, porosity of the aggregates, shrinkage characteristics of soil fraction in diameter of 3-5 mm. For the simulation the model "MACRO" (Jarvis et al, 1991) was used in the work. Adequacy of the model descriptions of the field data were estimated by visual comparison of measured and calculated data

  16. The dynamics of structures - Necessity and methodology for amendment by comparing the calculated model with experimental model

    International Nuclear Information System (INIS)

    Caneparo, B.; Zirilli, S.

    1987-01-01

    In this work relating to support structures for seismic tests, the authors present a mixed procedure necessitating the experimental measurement of natural frequencies, dampings, and the response to impulse stresses (in the case of a seismic stress, the subject of this study, a single impulse is sufficient) in the zone in question. Experimental measurements are used to adjust the finite elements model; it may then be used for later studies. In the presence of interaction with structures not included in the model, such as, for example, the means used for the actual test, it is impossible to adjust it according to the methods proposed and it is up to the experienced author to introduce the modifications judged opportune to take into account everything which is not a part of the model. The authors have, however, carried out a programme based on the local modification of Young's module, which uses only natural frequencies, useful in the adjustment process. Once the zone of poor modelling has been found, this programme enables optimizing the value of E as a function of the experimental data, whilst also furnishing an estimate of residual differences. Dynamic tests have shown that the model thus obtained can be refined by the forced impulse to an impulse stress. In addition to setting out the theories and formulae used, we then give account of verification of the methodology using a plate, and of its application to a support structure in the form of a frame for seismic tests. The appendices include both experimental measurements and tests. The authors carried out the modal analysis with even greater care than necessary in view of the methodology verification phase

  17. Computational modeling of RNA 3D structures, with the aid of experimental restraints

    Science.gov (United States)

    Magnus, Marcin; Matelska, Dorota; Łach, Grzegorz; Chojnowski, Grzegorz; Boniecki, Michal J; Purta, Elzbieta; Dawson, Wayne; Dunin-Horkawicz, Stanislaw; Bujnicki, Janusz M

    2014-01-01

    In addition to mRNAs whose primary function is transmission of genetic information from DNA to proteins, numerous other classes of RNA molecules exist, which are involved in a variety of functions, such as catalyzing biochemical reactions or performing regulatory roles. In analogy to proteins, the function of RNAs depends on their structure and dynamics, which are largely determined by the ribonucleotide sequence. Experimental determination of high-resolution RNA structures is both laborious and difficult, and therefore, the majority of known RNAs remain structurally uncharacterized. To address this problem, computational structure prediction methods were developed that simulate either the physical process of RNA structure formation (“Greek science” approach) or utilize information derived from known structures of other RNA molecules (“Babylonian science” approach). All computational methods suffer from various limitations that make them generally unreliable for structure prediction of long RNA sequences. However, in many cases, the limitations of computational and experimental methods can be overcome by combining these two complementary approaches with each other. In this work, we review computational approaches for RNA structure prediction, with emphasis on implementations (particular programs) that can utilize restraints derived from experimental analyses. We also list experimental approaches, whose results can be relatively easily used by computational methods. Finally, we describe case studies where computational and experimental analyses were successfully combined to determine RNA structures that would remain out of reach for each of these approaches applied separately. PMID:24785264

  18. Modeling and experimental verification of laser self-mixing interference phenomenon with the structure of two-external-cavity feedback

    Science.gov (United States)

    Chen, Peng; Liu, Yuwei; Gao, Bingkun; Jiang, Chunlei

    2018-03-01

    A semiconductor laser employed with two-external-cavity feedback structure for laser self-mixing interference (SMI) phenomenon is investigated and analyzed. The SMI model with two directions based on F-P cavity is deduced, and numerical simulation and experimental verification were conducted. Experimental results show that the SMI with the structure of two-external-cavity feedback under weak light feedback is similar to the sum of two SMIs.

  19. Modeling RNA Secondary Structure with Sequence Comparison and Experimental Mapping Data.

    Science.gov (United States)

    Tan, Zhen; Sharma, Gaurav; Mathews, David H

    2017-07-25

    Secondary structure prediction is an important problem in RNA bioinformatics because knowledge of structure is critical to understanding the functions of RNA sequences. Significant improvements in prediction accuracy have recently been demonstrated though the incorporation of experimentally obtained structural information, for instance using selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) mapping. However, such mapping data is currently available only for a limited number of RNA sequences. In this article, we present a method for extending the benefit of experimental mapping data in secondary structure prediction to homologous sequences. Specifically, we propose a method for integrating experimental mapping data into a comparative sequence analysis algorithm for secondary structure prediction of multiple homologs, whereby the mapping data benefits not only the prediction for the specific sequence that was mapped but also other homologs. The proposed method is realized by modifying the TurboFold II algorithm for prediction of RNA secondary structures to utilize basepairing probabilities guided by SHAPE experimental data when such data are available. The SHAPE-mapping-guided basepairing probabilities are obtained using the RSample method. Results demonstrate that the SHAPE mapping data for a sequence improves structure prediction accuracy of other homologous sequences beyond the accuracy obtained by sequence comparison alone (TurboFold II). The updated version of TurboFold II is freely available as part of the RNAstructure software package. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  20. New modeling and experimental approaches for characterization of two-phase flow interfacial structure

    International Nuclear Information System (INIS)

    Ishii, Mamoru; Sun, Xiaodong

    2004-01-01

    This paper presents new experimental and modeling approaches in characterizing interfacial structures in gas-liquid two-phase flow. For the experiments, two objective approaches are developed to identify flow regimes and to obtain local interfacial structure data. First, a global measurement technique using a non-intrusive ring-type impedance void-meter and a self-organizing neural network is presented to identify the one-dimensional'' flow regimes. In the application of this measurement technique, two methods are discussed, namely, one based on the probability density function of the impedance probe measurement (PDF input method) and the other based on the sorted impedance signals, which is essentially the cumulative probability distribution function of the impedance signals (instantaneous direct signal input method). In the latter method, the identification can be made close to instantaneously since the required signals can be acquired over a very short time period. In addition, a double-sensor conductivity probe can also be used to obtain ''local'' flow regimes by using the instantaneous direct signal input method with the bubble chord length information. Furthermore, a newly designed conductivity probe with multiple double-sensor heads is proposed to obtain ''two-dimensional'' flow regimes across the flow channel. Secondly, a state-of-the-art four-sensor conductivity probe technique has been developed to obtain detailed local interfacial structure information. The four-sensor conductivity probe accommodates the double-sensor probe capability and can be applied in a wide range of flow regimes spanning from bubbly to churn-turbulent flows. The signal processing scheme is developed such that it categorizes the acquired parameters into two groups based on bubble cord length information. Furthermore, for the modeling of the interfacial structure characterization, the interfacial area transport equation proposed earlier has been studied to provide a dynamic and

  1. Early-age behaviour of concrete in massive structures, experimentation and modelling

    International Nuclear Information System (INIS)

    Zreiki, J.; Bouchelaghem, F.; Chaouche, M.

    2010-01-01

    This study is focused on the behaviour of concrete at early-age in massive structures, in relation with the prediction of both cracking risk and residual stresses, which is still a challenging task. In this paper, a 3D thermo-chemo-mechanical model has been developed, on the basis of complete material characterization experiments, in order to predict the early-age development of strains and residual stresses, and in order to assess the risk of cracking in massive concrete structures. The parameters of the proposed model were identified on two different concretes, High Performance Concrete and Fibrous Self-Compacted Concrete - from simple experiments in the laboratory: uniaxial tension and compression tests, dynamic Young's modulus measurements, free and autogenous shrinkages, semi-adiabatic calorimetry. The proposed model has been implemented in a Finite Element code, and the numerical simulations of the laboratory tests have proved the model consistency. Furthermore, early-age experiments conducted on massive structures have also been simulated, in order to investigate the predictive capability of the model, and to assess the model performance in practical situations where varying temperatures are involved.

  2. Improved prediction of RNA secondary structure by integrating the free energy model with restraints derived from experimental probing data.

    Science.gov (United States)

    Wu, Yang; Shi, Binbin; Ding, Xinqiang; Liu, Tong; Hu, Xihao; Yip, Kevin Y; Yang, Zheng Rong; Mathews, David H; Lu, Zhi John

    2015-09-03

    Recently, several experimental techniques have emerged for probing RNA structures based on high-throughput sequencing. However, most secondary structure prediction tools that incorporate probing data are designed and optimized for particular types of experiments. For example, RNAstructure-Fold is optimized for SHAPE data, while SeqFold is optimized for PARS data. Here, we report a new RNA secondary structure prediction method, restrained MaxExpect (RME), which can incorporate multiple types of experimental probing data and is based on a free energy model and an MEA (maximizing expected accuracy) algorithm. We first demonstrated that RME substantially improved secondary structure prediction with perfect restraints (base pair information of known structures). Next, we collected structure-probing data from diverse experiments (e.g. SHAPE, PARS and DMS-seq) and transformed them into a unified set of pairing probabilities with a posterior probabilistic model. By using the probability scores as restraints in RME, we compared its secondary structure prediction performance with two other well-known tools, RNAstructure-Fold (based on a free energy minimization algorithm) and SeqFold (based on a sampling algorithm). For SHAPE data, RME and RNAstructure-Fold performed better than SeqFold, because they markedly altered the energy model with the experimental restraints. For high-throughput data (e.g. PARS and DMS-seq) with lower probing efficiency, the secondary structure prediction performances of the tested tools were comparable, with performance improvements for only a portion of the tested RNAs. However, when the effects of tertiary structure and protein interactions were removed, RME showed the highest prediction accuracy in the DMS-accessible regions by incorporating in vivo DMS-seq data. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. Validation of a numerical 3-D fluid-structure interaction model for a prosthetic valve based on experimental PIV measurements.

    Science.gov (United States)

    Guivier-Curien, Carine; Deplano, Valérie; Bertrand, Eric

    2009-10-01

    A numerical 3-D fluid-structure interaction (FSI) model of a prosthetic aortic valve was developed, based on a commercial computational fluid dynamics (CFD) software program using an Arbitrary Eulerian Lagrangian (ALE) formulation. To make sure of the validity of this numerical model, an equivalent experimental model accounting for both the geometrical features and the hydrodynamic conditions was also developed. The leaflet and the flow behaviours around the bileaflet valve were investigated numerically and experimentally by performing particle image velocimetry (PIV) measurements. Through quantitative and qualitative comparisons, it was shown that the leaflet behaviour and the velocity fields were similar in both models. The present study allows the validation of a fully coupled 3-D FSI numerical model. The promising numerical tool could be therefore used to investigate clinical issues involving the aortic valve.

  4. Ab initio structural modeling of and experimental validation for Chlamydia trachomatis protein CT296 reveal structural similarity to Fe(II) 2-oxoglutarate-dependent enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Kemege, Kyle E.; Hickey, John M.; Lovell, Scott; Battaile, Kevin P.; Zhang, Yang; Hefty, P. Scott (Michigan); (Kansas); (HWMRI)

    2012-02-13

    Chlamydia trachomatis is a medically important pathogen that encodes a relatively high percentage of proteins with unknown function. The three-dimensional structure of a protein can be very informative regarding the protein's functional characteristics; however, determining protein structures experimentally can be very challenging. Computational methods that model protein structures with sufficient accuracy to facilitate functional studies have had notable successes. To evaluate the accuracy and potential impact of computational protein structure modeling of hypothetical proteins encoded by Chlamydia, a successful computational method termed I-TASSER was utilized to model the three-dimensional structure of a hypothetical protein encoded by open reading frame (ORF) CT296. CT296 has been reported to exhibit functional properties of a divalent cation transcription repressor (DcrA), with similarity to the Escherichia coli iron-responsive transcriptional repressor, Fur. Unexpectedly, the I-TASSER model of CT296 exhibited no structural similarity to any DNA-interacting proteins or motifs. To validate the I-TASSER-generated model, the structure of CT296 was solved experimentally using X-ray crystallography. Impressively, the ab initio I-TASSER-generated model closely matched (2.72-{angstrom} C{alpha} root mean square deviation [RMSD]) the high-resolution (1.8-{angstrom}) crystal structure of CT296. Modeled and experimentally determined structures of CT296 share structural characteristics of non-heme Fe(II) 2-oxoglutarate-dependent enzymes, although key enzymatic residues are not conserved, suggesting a unique biochemical process is likely associated with CT296 function. Additionally, functional analyses did not support prior reports that CT296 has properties shared with divalent cation repressors such as Fur.

  5. Analysis of the structural behaviour of colonic segments by inflation tests: Experimental activity and physio-mechanical model.

    Science.gov (United States)

    Carniel, Emanuele L; Mencattelli, Margherita; Bonsignori, Gabriella; Fontanella, Chiara G; Frigo, Alessandro; Rubini, Alessandro; Stefanini, Cesare; Natali, Arturo N

    2015-11-01

    A coupled experimental and computational approach is provided for the identification of the structural behaviour of gastrointestinal regions, accounting for both elastic and visco-elastic properties. The developed procedure is applied to characterize the mechanics of gastrointestinal samples from pig colons. Experimental data about the structural behaviour of colonic segments are provided by inflation tests. Different inflation processes are performed according to progressively increasing top pressure conditions. Each inflation test consists of an air in-flow, according to an almost constant increasing pressure rate, such as 3.5 mmHg/s, up to a prescribed top pressure, which is held constant for about 300 s to allow the development of creep phenomena. Different tests are interspersed by 600 s of rest to allow the recovery of the tissues' mechanical condition. Data from structural tests are post-processed by a physio-mechanical model in order to identify the mechanical parameters that interpret both the non-linear elastic behaviour of the sample, as the instantaneous pressure-stretch trend, and the time-dependent response, as the stretch increase during the creep processes. The parameters are identified by minimizing the discrepancy between experimental and model results. Different sets of parameters are evaluated for different specimens from different pigs. A statistical analysis is performed to evaluate the distribution of the parameters and to assess the reliability of the experimental and computational activities. © IMechE 2015.

  6. Crack Detection in Fibre Reinforced Plastic Structures Using Embedded Fibre Bragg Grating Sensors: Theory, Model Development and Experimental Validation

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    properties. When applying this concept to different structures, sensor systems and damage types, a combination of damage mechanics, monitoring technology, and modelling is required. The primary objective of this article is to demonstrate such a combination. This article is divided in three main topics...... a crack growth/damage event in fibre-reinforced polymer or structural adhesive-bonded structures using embedded fibre Bragg grating (FBG) sensors is presented by combining conventional measured parameters, such as wavelength shift, with parameters associated with measurement errors, typically ignored...... instrumented with an array of FBG sensors embedded in the material and tested using an experimental fracture procedure. The digital image correlation technique was used to validate the model prediction by correlating the specific sensor response caused by the crack with the developed model....

  7. Crack Detection in Fibre Reinforced Plastic Structures Using Embedded Fibre Bragg Grating Sensors: Theory, Model Development and Experimental Validation.

    Directory of Open Access Journals (Sweden)

    G F Pereira

    Full Text Available In a fibre-reinforced polymer (FRP structure designed using the emerging damage tolerance and structural health monitoring philosophy, sensors and models that describe crack propagation will enable a structure to operate despite the presence of damage by fully exploiting the material's mechanical properties. When applying this concept to different structures, sensor systems and damage types, a combination of damage mechanics, monitoring technology, and modelling is required. The primary objective of this article is to demonstrate such a combination. This article is divided in three main topics: the damage mechanism (delamination of FRP, the structural health monitoring technology (fibre Bragg gratings to detect delamination, and the finite element method model of the structure that incorporates these concepts into a final and integrated damage-monitoring concept. A novel method for assessing a crack growth/damage event in fibre-reinforced polymer or structural adhesive-bonded structures using embedded fibre Bragg grating (FBG sensors is presented by combining conventional measured parameters, such as wavelength shift, with parameters associated with measurement errors, typically ignored by the end-user. Conjointly, a novel model for sensor output prediction (virtual sensor was developed using this FBG sensor crack monitoring concept and implemented in a finite element method code. The monitoring method was demonstrated and validated using glass fibre double cantilever beam specimens instrumented with an array of FBG sensors embedded in the material and tested using an experimental fracture procedure. The digital image correlation technique was used to validate the model prediction by correlating the specific sensor response caused by the crack with the developed model.

  8. Design and experimental validation of a generic model for combinatorial assembly of DNA tiles into 1D-structures.

    Science.gov (United States)

    Laisne, Aude; Lesniewska, Eric; Pompon, Denis

    2011-06-01

    Quantitative modeling of the self-assembly of DNA tiles leading either to defined end-products or distribution of biopolymers is of practical importance for biotechnology and synthetic biology. The combinatorial process describing tile assembly was implemented into a generic algorithm allowing quantitative description of the population of significant species accumulating during the reaction course. Experimental formation and characterization by optical and electrophoresis approaches of copolymers resulting from the self-assembly of a limited number of half-complementary tiles were used to define and validate generic rules allowing definition of model parameters. Factors controlling the structure and the dynamic of the oligomer population were evidenced for assemblies leading or not to defined end-products. Primary parameters were experimentally determined using rapid mixing experiments. Adjustment of simulations to experimental profiles allowed definition of generic rules for calculation of secondary parameters that take into account macro- and microenvironment of individual hybridization steps. In the case of copolymers, accurate simulation of experimental profiles was achieved for formation of linear assemblies. Overall length of species and structure of the DNA regions flanking the hybridization sites are critical parameters for which calculation rules were defined. The computational approach quantitatively predicted the parameters affecting time-course and distribution of accumulating products for different experimental designs. The computational and parameter evaluation procedures designed for the assembly of DNA tiles into large 1D-structures are more generally applicable for the construction of non-DNA polymers by extremities-specific recognition of molecular blocks. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. STRUCTURAL MODELLING

    Directory of Open Access Journals (Sweden)

    Tea Ya. Danelyan

    2014-01-01

    Full Text Available The article states the general principles of structural modeling in aspect of the theory of systems and gives the interrelation with other types of modeling to adjust them to the main directions of modeling. Mathematical methods of structural modeling, in particular method of expert evaluations are considered.

  10. Experimental and numerical modelling of ductile crack propagation in large-scale shell structures

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup; Törnquist, R.

    2004-01-01

    plastic and controlled conditions. The test specimen can be deformed either in combined in-plane bending and extension or in pure extension. Experimental results are described for 5 and 10 mm thick aluminium and steel plates. By performing an inverse finite-element analysis of the experimental results...... where the simulated crack growth is forced to correspond to the experimental observations, empirical criteria for ductile crack propagation emerge very cleary. Using the experiments with edge crack specimens (ECS) in combined in-plane bending and extension, crack propagation criteria are developed...

  11. Fly's proprioception-inspired micromachined strain-sensing structure: idea, design, modeling and simulation, and comparison with experimental results

    Science.gov (United States)

    Wicaksono, D. H. B.; Zhang, L.-J.; Pandraud, G.; French, P. J.; Vincent, J. F. V.

    2006-04-01

    A new strain-sensing structure inspired from insect's (especially the Fly) propricoception sensor is devised. The campaniform sensillum is a strain-sensing microstructure with very high sensitivity despite its small dimension (diameter ~10 µm in a relatively stiff material of insect's exocuticle (E = ~109 Pa). Previous work shows that the high sensitivity of this structure towards strain is due to its membrane-in-recess- and strainconcentrating- hole- features. Based on this inspiration, we built similar structure using silicon micromachining technology. Then a simple characterisation setup was devised. Here, we present briefly, finite-element modeling and simulation based on this actual sample preparation for the characterisation. As comparison and also to understand mechanical features responsible for the strain-sensitivity, we performed the modeling on different mechanical structures: bulk chunk, blind-hole, thorugh-hole, surface membrane, and membrane-in-recess. The actual experimental characterisation was performed previously using optical technique to membranein- recess micromachined Si structure. The FEM simulation results confirm that the bending stress and strain are concentrated in the hole-vicinity. The membrane inside the hole acts as displacement transducer. The FEM is in conformity with previous analytical results, as well as the optical characterisation result. The end goal is to build a new type MEMS strain sensor.

  12. The social structure of experimental'' strings at Fermilab; a physics and detector driven model

    Energy Technology Data Exchange (ETDEWEB)

    Bodnarczuk, M.

    1990-12-12

    Physicists in HEP have been forced to organize large scientific projects without a well defined organizational or sociological model to guide them. In the absence of such models, what structures do experimentalists use to develop social structures in HEP In this paper, I claim that physicists organize around what they know best, the physics problems they study and the detectors and devices they study them with. After describing the advent of management'' in HEP, I use a case study of 4 Fermilab experiments as the base upon which to propose a physics and detector driven model of social structure for experiments. In addition, I show how this model can be extended to describe strings'' of experiments, where continuities of physics interests, spectrometer design, and a core group of physicists become a definable sociological unit that can exist for over 15 years. A dominate theme that emerges from my analysis is the conscious attempt on the part of experimenters to remove the uncertainties that are part of the practice of HEP.

  13. Effect of cyclic training model on terminal structure of rabbit Achilles tendon: an experimental study

    Directory of Open Access Journals (Sweden)

    Chang-lin HUANG

    2012-05-01

    group at the early stage, but there was an increase at the late stage of the training (6 weeks later, however the score values were lower than those in the jumping group and running group. These changes in score were originated mainly from pathological changes in the paratenon and tidemark. Conclusions  Jumping training could lead to severe injury to the fiber tissue and fibrocartilage, while running training might result in severe injury to Achilles tendon insertion structure and lighter injury to the fibrocartilage part. Cyclic training model provides suffcient time for repair and reconstruction of Achilles tendon insertion structure, and decrease the severity of the injury to Achilles tendon insertion region. Therefore, use of cyclic training could not only effectively prevent training-based enthesiopathy, but also accelerate the remodeling of the tissue in the insertion region, thus strengthen the repair ability of Achilles tendon against injury.

  14. Combined numerical-experimental model for the identification of mechanical properties of laminated structures

    DEFF Research Database (Denmark)

    Araujo, A.L.; Mota Soares, C.M.; Moreira de Freitas, M.J.

    2000-01-01

    A combined numerical-experimental method for the identification of six elastic material modulus of generally thick composite plates is proposed in this paper. This technique can be used in composite plates made of different materials and with general stacking sequences. It makes use of experiment...

  15. Tensegrity structures - Computational and experimental tensegrity mechanics

    Science.gov (United States)

    Kuhl, Detlef; Lim, Yi Chung; Long, David S.

    2017-07-01

    The present paper deals with tensegrity structures. We review the definition of tensegrity structures, and describe both experimental and computational form finding methods. Also described are the numerical methods for the simulation of prestress induced stiffness, and the static and dynamic structural analyses. Furthermore, we present laboratory models and measurement methods for identifying the realized geometry and prestress state. Finally, computationally and experimentally obtained geometries and prestress states are compared, a representative realization of a real world tensegrity tower is shown and the modeling of biological cells as tensegrity structures is adressed.

  16. Micronozzles: 3D numerical structural and gas dynamics modeling, fabrication, and preliminary experimental results

    Science.gov (United States)

    Borovkov, Alexei I.; Pyatishev, Evgenij N.; Lurie, Mihail S.; Korshunov, Andrey V.; Akulshin, Y. D.; Dolganov, A. G.; Sabadash, V. O.

    2001-02-01

    The tiny engines, founded on the principle of reactive thrust, are one of most perspective actuators developed by modern micromechanics. These engines can be applied for such apparent problems, as orientation and stabilization of small space objects, but also as local or distributed reactive thrust of new phylum of aerospace objects, for control of boundary layer of flying objects and in series of converting power devices of different purposes. Distinctive features of jet tiny engines are profitability (very large thrust-to-weight ratio) and high (milliseconds) response, which makes them to irreplaceable elements in control systems and, specially, in distributed power generations. These features are provided the minimum sizes, high pressure in working chambers and hypersonic velocity of propulsive jet. Topologically micronozzles are designed as the flat batch devices (3 layers as minimum). The lower and upper layers make flat walls of the nozzle and mainly influence on strength properties of the device. The mean layer reshapes geometry and determines gas dynamic characteristic of the nozzle. A special problem is the opening-up of the combustion-mixture, which is not esteemed in this work. It is necessary to allow for effect of considerable local stresses arising at the expense of static and dynamic loading at design of the jet tiny engines. Thermal gas dynamic processes in the chamber and nozzle determine the values and nature of these stresses, which are hardly studied for the microdevices. The priority is mathematical and experimental simulation of these processes. The most suitable object for initial phase of experimental simulation is the 'cold' engine. The demanded chamber static pressure is formed by external compressed air. In Laboratory of Microtechnology and MicroElectroMechanical Systems a number of such tiny engines with different shapes of the chamber's and the nozzles' surfaces were designed, made and tested. The engines were produced from photosensing

  17. Intercalates of strontium phenylphosphonate with alcohols - Structure analysis by experimental and molecular modeling methods

    Czech Academy of Sciences Publication Activity Database

    Zima, Vítězslav; Melánová, Klára; Kovář, P.; Beneš, L.; Svoboda, Jan; Pospíšil, M.; Růžička, A.

    2015-01-01

    Roč. 2015, č. 9 (2015), s. 1552-1561 ISSN 1434-1948 R&D Projects: GA ČR(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : layered compounds * intercalation * molecular modeling Subject RIV: CA - Inorganic Chemistry Impact factor: 2.686, year: 2015

  18. Effect of cyclic training model on terminal structure of rabbit Achilles tendon: an experimental study

    OpenAIRE

    Chang-lin HUANG; Wang GAO; Tao HUANG; Zhen-hai GUO

    2012-01-01

    Objective  To observe the effect of cyclic training on histomorphology of the terminal structure of rabbit Achilles tendon, and explore its preventive effect on training-based enthesiopathy. Methods  Seventy-two Japanese white rabbits were randomly assigned to four groups: control group, jumping group, running group and cyclic training group, 18 for each. Three rabbits of each group were sacrificed at the 2nd, 3rd, 4th, 6th, 8th and 10th week. The terminal insertion tissues of bilateral Achil...

  19. Modeling Aerobic Carbon Source Degradation Processes using Titrimetric Data and Combined Respirometric-Titrimetric Data: Experimental Data and Model Structure

    DEFF Research Database (Denmark)

    Gernaey, Krist; Petersen, B.; Nopens, I.

    2002-01-01

    Experimental data are presented that resulted from aerobic batch degradation experiments in activated sludge with simple carbon sources (acetate and dextrose) as substrates. Data collection was done using combined respirometric-titrimetric measurements. The respirometer consists of an open aerated...... vessel and a closed non-aerated respiration chamber for monitoring the oxygen uptake rate related to substrate degradation. The respirometer is combined with a titrimetric unit that keeps the pH of the activated sludge sample at a constant value by addition of acid and/or base. The experimental data...... clearly showed that the activated sludge bacteria react with consumption or production of protons during aerobic degradation of the two carbon sources under study. Thus, the cumulative amount of added acid and/or base could serve as a complementary information source on the degradation processes...

  20. Experimental study of structural response to earthquakes

    International Nuclear Information System (INIS)

    Clough, R.W.; Bertero, V.V.; Bouwkamp, J.G.; Popov, E.P.

    1975-01-01

    The objectives, methods, and some of the principal results obtained from experimental studies of the behavior of structures subjected to earthquakes are described. Although such investigations are being conducted in many laboratories throughout the world, the information presented deals specifically with projects being carried out at the Earthquake Engineering Research Center (EERC) of the University of California, Berkeley. A primary purpose of these investigations is to obtain detailed information on the inelastic response mechanisms in typical structural systems so that the experimentally observed performance can be compared with computer generated analytical predictions. Only by such comparisons can the mathematical models used in dynamic nonlinear analyses be verified and improved. Two experimental procedures for investigating earthquake structural response are discussed: the earthquake simulator facility which subjects the base of the test structure to acceleration histories similar to those recorded in actual earthquakes, and systems of hydraulic rams which impose specified displacement histories on the test components, equivalent to motions developed in structures subjected to actual'quakes. The general concept and performance of the 20ft square EERC earthquake simulator is described, and the testing of a two story concrete frame building is outlined. Correlation of the experimental results with analytical predictions demonstrates that satisfactory agreement can be obtained only if the mathematical model incorporates a stiffness deterioration mechanism which simulates the cracking and other damage suffered by the structure

  1. Experimental Modeling of Dynamic Systems

    DEFF Research Database (Denmark)

    Knudsen, Morten Haack

    2006-01-01

    An engineering course, Simulation and Experimental Modeling, has been developed that is based on a method for direct estimation of physical parameters in dynamic systems. Compared with classical system identification, the method appears to be easier to understand, apply, and combine with physical...... insight. It is based on a sensitivity approach that is useful for choice of model structure, for experiment design, and for accuracy verification. The method is implemented in the Matlab toolkit Senstools. The method and the presentation have been developed with generally preferred learning styles in mind...

  2. Numerical modeling and experimental validation of the acoustic transmission of aircraft's double-wall structures including sound package

    Science.gov (United States)

    Rhazi, Dilal

    to address this need. A numerical tool based on two approaches (Wave and Modal) is developed. It allows a fast computation of the vibroacoustic response for multilayer structures over full frequency spectrum and for various kinds of excitations (monople, rain on the roof, diffuse acoustic filed, turbulent boundary layer) . A comparison between results obtained by the developed model, experimental tests and the finite element method is given and discussed. The results are very promising with respect to the potential of such a model for industrial use as a prediction tool, and even for design. The code can be also integrated within an SEA (Statistical Energy Analysis) strategy in order to model a full vehicle by computing in particular the insertion loss and the equivalent damping added by the sound package. Keywords: Transfer Matrix Method, Wave Approach,Turbulent Boundary Layer, Rain on the Roof, Monopole, Insertion loss, Double-wall, Sound Package.

  3. Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed structural panels in bending

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2017-01-01

    This paper presents an analysis of 3-dimensional engineered structural panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model...

  4. Experimental modelling of the consequences of brief late gestation asphyxia on newborn lamb behaviour and brain structure.

    Directory of Open Access Journals (Sweden)

    Margie Castillo-Melendez

    Full Text Available Brief but severe asphyxia in late gestation or at the time of birth may lead to neonatal hypoxic ischemic encephalopathy and is associated with long-term neurodevelopmental impairment. We undertook this study to examine the consequences of transient in utero asphyxia in late gestation fetal sheep, on the newborn lamb after birth. Surgery was undertaken at 125 days gestation for implantation of fetal catheters and placement of a silastic cuff around the umbilical cord. At 132 days gestation (0.89 term, the cuff was inflated to induce umbilical cord occlusion (UCO, or sham (control. Fetal arterial blood samples were collected for assessment of fetal wellbeing and the pregnancy continued until birth. At birth, behavioral milestones for newborn lambs were recorded over 24 h, after which the lambs were euthanased for brain collection and histopathology assessments. After birth, UCO lambs displayed significant latencies to (i use all four legs, (ii attain a standing position, (iii find the udder, and (iv successfully suckle--compared to control lambs. Brains of UCO lambs showed widespread pathologies including cell death, white matter disruption, intra-parenchymal hemorrhage and inflammation, which were not observed in full term control brains. UCO resulted in some preterm births, but comparison with age-matched preterm non-UCO control lambs showed that prematurity per se was not responsible for the behavioral delays and brain structural abnormalities resulting from the in utero asphyxia. These results demonstrate that a single, brief fetal asphyxic episode in late gestation results in significant grey and white matter disruption in the developing brain, and causes significant behavioral delay in newborn lambs. These data are consistent with clinical observations that antenatal asphyxia is causal in the development of neonatal encephalopathy and provide an experimental model to advance our understanding of neuroprotective therapies.

  5. Experimental Modelling of the Consequences of Brief Late Gestation Asphyxia on Newborn Lamb Behaviour and Brain Structure

    Science.gov (United States)

    Yawno, Tamara; Witjaksono, Anissa; Miller, Suzie L.; Walker, David W.

    2013-01-01

    Brief but severe asphyxia in late gestation or at the time of birth may lead to neonatal hypoxic ischemic encephalopathy and is associated with long-term neurodevelopmental impairment. We undertook this study to examine the consequences of transient in utero asphyxia in late gestation fetal sheep, on the newborn lamb after birth. Surgery was undertaken at 125 days gestation for implantation of fetal catheters and placement of a silastic cuff around the umbilical cord. At 132 days gestation (0.89 term), the cuff was inflated to induce umbilical cord occlusion (UCO), or sham (control). Fetal arterial blood samples were collected for assessment of fetal wellbeing and the pregnancy continued until birth. At birth, behavioral milestones for newborn lambs were recorded over 24 h, after which the lambs were euthanased for brain collection and histopathology assessments. After birth, UCO lambs displayed significant latencies to (i) use all four legs, (ii) attain a standing position, (iii) find the udder, and (iv) successfully suckle - compared to control lambs. Brains of UCO lambs showed widespread pathologies including cell death, white matter disruption, intra-parenchymal hemorrhage and inflammation, which were not observed in full term control brains. UCO resulted in some preterm births, but comparison with age-matched preterm non-UCO control lambs showed that prematurity per se was not responsible for the behavioral delays and brain structural abnormalities resulting from the in utero asphyxia. These results demonstrate that a single, brief fetal asphyxic episode in late gestation results in significant grey and white matter disruption in the developing brain, and causes significant behavioral delay in newborn lambs. These data are consistent with clinical observations that antenatal asphyxia is causal in the development of neonatal encephalopathy and provide an experimental model to advance our understanding of neuroprotective therapies. PMID:24223120

  6. Analysis of the dynamic behavior of structures using the high-rate GNSS-PPP method combined with a wavelet-neural model: Numerical simulation and experimental tests

    Science.gov (United States)

    Kaloop, Mosbeh R.; Yigit, Cemal O.; Hu, Jong W.

    2018-03-01

    Recently, the high rate global navigation satellite system-precise point positioning (GNSS-PPP) technique has been used to detect the dynamic behavior of structures. This study aimed to increase the accuracy of the extraction oscillation properties of structural movements based on the high-rate (10 Hz) GNSS-PPP monitoring technique. A developmental model based on the combination of wavelet package transformation (WPT) de-noising and neural network prediction (NN) was proposed to improve the dynamic behavior of structures for GNSS-PPP method. A complicated numerical simulation involving highly noisy data and 13 experimental cases with different loads were utilized to confirm the efficiency of the proposed model design and the monitoring technique in detecting the dynamic behavior of structures. The results revealed that, when combined with the proposed model, GNSS-PPP method can be used to accurately detect the dynamic behavior of engineering structures as an alternative to relative GNSS method.

  7. Experimental Object-Oriented Modelling

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    and discuss techniques for handling and representing uncertainty when modelling in experimental system development. These techniques are centred on patterns and styles for handling uncertainty in object-oriented software architectures. Tools We present the Knight tool designed for collaborative modelling...... in experimental system development and discuss its design, implementation, and evaluation. The tool has subsequently been successfully commercialized. In summary, this thesis presents techniques and tools that advance the effectiveness and efficiency of experimental modelling.......This thesis examines object-oriented modelling in experimental system development. Object-oriented modelling aims at representing concepts and phenomena of a problem domain in terms of classes and objects. Experimental system development seeks active experimentation in a system development project...

  8. Effects of Ice-Crystal Structure on Halo Formation: Cirrus Cloud Experimental and Ray-Tracing Modeling Studies

    Science.gov (United States)

    Sassen, Kenneth; Knight, Nancy C.; Takano, Yoshihide; Heymsfield, Andrew J.

    1994-01-01

    During the 1986 Project FIRE (First International Satellite Cloud Climatology Project Regional Experiment) field campaign, four 22 deg halo-producing cirrus clouds were studied jointly from a ground-based polarization lidar and an instrumented aircraft. The lidar data show the vertical cloud structure and the relative position of the aircraft, which collected a total of 84 slides by impaction, preserving the ice crystals for later microscopic examination. Although many particles were too fragile to survive impaction intact, a large fraction of the identifiable crystals were columns and radial bullet rosettes, with both displaying internal cavitations and radial plate-column combinations. Particles that were solid or displayed only a slight amount of internal structure were relatively rare, which shows that the usual model postulated by halo theorists, i.e., the randomly oriented, solid hexagonal crystal, is inappropriate for typical cirrus clouds. With the aid of new ray-tracing simulations for hexagonal hollow-ended column and bullet-rosette models, we evaluate the effects of more realistic ice-crystal structures on halo formation and lidar depolarization and consider why the common halo is not more common in cirrus clouds.

  9. Experimental Validation of an Integrated Controls-Structures Design Methodology

    Science.gov (United States)

    Maghami, Peiman G.; Gupta, Sandeep; Elliot, Kenny B.; Walz, Joseph E.

    1996-01-01

    The first experimental validation of an integrated controls-structures design methodology for a class of large order, flexible space structures is described. Integrated redesign of the controls-structures-interaction evolutionary model, a laboratory testbed at NASA Langley, was described earlier. The redesigned structure was fabricated, assembled in the laboratory, and experimentally tested against the original structure. Experimental results indicate that the structure redesigned using the integrated design methodology requires significantly less average control power than the nominal structure with control-optimized designs, while maintaining the required line-of-sight pointing performance. Thus, the superiority of the integrated design methodology over the conventional design approach is experimentally demonstrated. Furthermore, amenability of the integrated design structure to other control strategies is evaluated, both analytically and experimentally. Using Linear-Quadratic-Guassian optimal dissipative controllers, it is observed that the redesigned structure leads to significantly improved performance with alternate controllers as well.

  10. Model refinement for offshore platforms: Experimental study

    Science.gov (United States)

    Zhang, Min; Chen, Zongli; Wu, Yanjian

    2017-08-01

    Offshore jacket platforms are widely used in offshore oil and gas exploitation. Finite element models of such structures need to have many degrees of freedom (DOFs) to represent the geometrical detail of complex structures, thereby leading to incompatibility in the number of DOFs of experimental models. To bring them both to the same order while ensuring that the essential eigen- properties of the refined model match those of experimental models, an extended model refinement procedure is presented in this paper. Vibration testing of an offshore jacket platform model is performed to validate the applicability of the proposed approach. A full-order finite element model of the platform is established and then tuned to meet the measured modal properties identified from the acceleration signals. Both model reduction and modal expansion methods are investigated, as well as various scenarios of sensor arrangements. Upon completion of the refinement, the updated jacket platform model matches the natural frequencies of the measured model well.

  11. Deformation and Recrystallization Behavior of the Cast Structure in Large Size, High Strength Steel Ingots: Experimentation and Modeling

    Science.gov (United States)

    Chadha, K.; Shahriari, D.; Tremblay, R.; Bhattacharjee, P. P.; Jahazi, M.

    2017-09-01

    Constitutive modeling of the ingot breakdown process of large size ingots of high strength steel was carried out through comprehensive thermomechanical processing using Gleeble 3800® thermomechanical simulator, finite element modeling (FEM), optical and electron back scatter diffraction (EBSD). For this purpose, hot compression tests in the range of 1473 K to 1323 K (1200 °C to 1050 °C) and strain rates of 0.25 to 2 s-1 were carried out. The stress-strain curves describing the deformation behavior of the dendritic microstructure of the cast ingot were analyzed in terms of the Arrhenius and Hansel-Spittel models which were implemented in Forge NxT 1.0® FEM software. The results indicated that the Arrhenius model was more reliable in predicting microstructure evolution of the as-cast structure during ingot breakdown, particularly the occurrence of dynamic recrystallization (DRX) process which was a vital parameter in estimating the optimum loads for forming of large size components. The accuracy and reliability of both models were compared in terms of correlation coefficient (R) and the average absolute relative error (ARRE).

  12. Analysis of Kinetic and Operational Parameters in a Structured Model for Acrylic Acid Production through Experimental Design

    Science.gov (United States)

    Lunelli, B. H.; Rivera, E. C.; Vasco de Toledo, E. C.; Maciel, M. R. Wolf; Filho, R. Maciel

    In biotechnological processes, a great number of factors can influence the income productivity and conversion. Normally, it is not evident which of these factors are the most important and how they interact. In this work, multivariate analysis techniques are used as experimental design coupled to a detailed deterministic model to identify the parameters with the most significant impact on the model to represent well the acrylic acid production process. It is proposed as an alternative process, having sugarcane as feedstock, to the petrochemical-based ones that have significant environmental impacts for their production. To increase the competitiveness of renewable acrylic-acid-based process, it is necessary to find out working conditions near the optimal region, which is not an easy task, as the process is multivariable and non-linear. The mapping of the dynamics of the developed process is made using techniques of factorial design together with the methodology of Plackett-Burman. It is shown that it is possible to increase the process performance by choosing optimized conditions for the reactor operation.

  13. The role of childhood trauma, early maladaptive schemas, emotional schemas and experimental avoidance on depression: A structural equation modeling.

    Science.gov (United States)

    Rezaei, Mehdi; Ghazanfari, Firoozeh; Rezaee, Fatemeh

    2016-12-30

    The present investigation was designed to examine disconnection and rejection (DR) schemas, negative emotional schemas (NESs) and experimental avoidance (EA) as mediating variables of the relationship between the childhood trauma (CT) and depression. Specifically we examined the mediating role of NESs and EA between DR schemas and depression. The study sample consist of 439 female college students (M age =22.47; SD=6.0), of whom 88 met the criteria for current major depressive disorder (MDD) and 351 who had history of MDD in the last 12 months. Subjects were assessed by Structured Clinical Interview for DSM-IV (SCID) and completed the Childhood Trauma Questionnaire (CTQ), the Early Maladaptive Schemas Questionnaire (SQ-SF), the Leahy Emotional Schemas Scale (LESS), the Acceptance and Action Questionnaire (AAQ-II), and the Beck Depression Inventory-II (BDI-II). The findings showed that DR schemas were mediator of the relationship CT and depression but CT through the NESs and EA did not predict depression. NESs were mediator of the relationship between DR schemas and depression and EA was mediator of the relationship between DR schemas and depression. In general, results suggest that intervention of depressed women may need to target the changing of DR schemas, NESs and reduction of EA. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Structural Workshop Paper --Descriptive, Structural, and Experimental Empirical Methods in Marketing Research

    OpenAIRE

    Peter C. Reiss

    2011-01-01

    What can be learned about marketing phenomena from descriptive, structural, and experimental empirical models? Is structure implicit in a descriptive empirical model? What is a "reduced-form model?" What is a natural experiment, and what can one infer from a study that uses experimental data? Having clear answers to these questions can improve empirical dialog. This paper defines descriptive, structural, and experimental empirical work, provides examples, discusses their similarities and diff...

  15. Novel Crack Stopper Concept for Lightweight Foam Cored Sandwich StructuresExperimental Validation, Fe-Modelling and Potential for Use in Structures

    DEFF Research Database (Denmark)

    Martakos, Georgios; Andreasen, Jens H.; Berggreen, Christian

    A novel crack arresting device has been implemented in foam cored composite sandwich beams panels and tested under both static and fatigue loading conditions. Fatigue crack propagation was induced in the face-core interface of the sandwich panels which met the crack arrester. The effect...... of the embedded crack arresters was evaluated in terms of the achieved enhancement of the damage tolerance of the tested sandwich beams and panels. Finite element (FE) modelling of the experimental setups was used for predicting propagation rates and direction of the crack growth. The FE model predicts the energy...... sandwich beam and panel specimens subjected to fatigue loading conditions. The effect of the crack arresters on the fatigue life is analysed, and the predictive results are subsequently compared with the observations from fatigue tests. Overall it was demonstrated that the proposed crack arrester device...

  16. Continuous mutual improvement of macromolecular structure models in the PDB and of X-ray crystallographic software: the dual role of deposited experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87507 (United States); Bricogne, Gerard, E-mail: terwilliger@lanl.gov [Global Phasing Ltd, Sheraton House, Castle Park, Cambridge CB3 0AX (United Kingdom); Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87507 (United States)

    2014-10-01

    Macromolecular structures deposited in the PDB can and should be continually reinterpreted and improved on the basis of their accompanying experimental X-ray data, exploiting the steady progress in methods and software that the deposition of such data into the PDB on a massive scale has made possible. Accurate crystal structures of macromolecules are of high importance in the biological and biomedical fields. Models of crystal structures in the Protein Data Bank (PDB) are in general of very high quality as deposited. However, methods for obtaining the best model of a macromolecular structure from a given set of experimental X-ray data continue to progress at a rapid pace, making it possible to improve most PDB entries after their deposition by re-analyzing the original deposited data with more recent software. This possibility represents a very significant departure from the situation that prevailed when the PDB was created, when it was envisioned as a cumulative repository of static contents. A radical paradigm shift for the PDB is therefore proposed, away from the static archive model towards a much more dynamic body of continuously improving results in symbiosis with continuously improving methods and software. These simultaneous improvements in methods and final results are made possible by the current deposition of processed crystallographic data (structure-factor amplitudes) and will be supported further by the deposition of raw data (diffraction images). It is argued that it is both desirable and feasible to carry out small-scale and large-scale efforts to make this paradigm shift a reality. Small-scale efforts would focus on optimizing structures that are of interest to specific investigators. Large-scale efforts would undertake a systematic re-optimization of all of the structures in the PDB, or alternatively the redetermination of groups of structures that are either related to or focused on specific questions. All of the resulting structures should be

  17. Partial Least Squares with Structured Output for Modelling the Metabolomics Data Obtained from Complex Experimental Designs: A Study into the Y-Block Coding.

    Science.gov (United States)

    Xu, Yun; Muhamadali, Howbeer; Sayqal, Ali; Dixon, Neil; Goodacre, Royston

    2016-10-28

    Partial least squares (PLS) is one of the most commonly used supervised modelling approaches for analysing multivariate metabolomics data. PLS is typically employed as either a regression model (PLS-R) or a classification model (PLS-DA). However, in metabolomics studies it is common to investigate multiple, potentially interacting, factors simultaneously following a specific experimental design. Such data often cannot be considered as a "pure" regression or a classification problem. Nevertheless, these data have often still been treated as a regression or classification problem and this could lead to ambiguous results. In this study, we investigated the feasibility of designing a hybrid target matrix Y that better reflects the experimental design than simple regression or binary class membership coding commonly used in PLS modelling. The new design of Y coding was based on the same principle used by structural modelling in machine learning techniques. Two real metabolomics datasets were used as examples to illustrate how the new Y coding can improve the interpretability of the PLS model compared to classic regression/classification coding.

  18. Partial Least Squares with Structured Output for Modelling the Metabolomics Data Obtained from Complex Experimental Designs: A Study into the Y-Block Coding

    Directory of Open Access Journals (Sweden)

    Yun Xu

    2016-10-01

    Full Text Available Partial least squares (PLS is one of the most commonly used supervised modelling approaches for analysing multivariate metabolomics data. PLS is typically employed as either a regression model (PLS-R or a classification model (PLS-DA. However, in metabolomics studies it is common to investigate multiple, potentially interacting, factors simultaneously following a specific experimental design. Such data often cannot be considered as a “pure” regression or a classification problem. Nevertheless, these data have often still been treated as a regression or classification problem and this could lead to ambiguous results. In this study, we investigated the feasibility of designing a hybrid target matrix Y that better reflects the experimental design than simple regression or binary class membership coding commonly used in PLS modelling. The new design of Y coding was based on the same principle used by structural modelling in machine learning techniques. Two real metabolomics datasets were used as examples to illustrate how the new Y coding can improve the interpretability of the PLS model compared to classic regression/classification coding.

  19. Fly's proprioception-inspired micromachined strain-sensing structure: idea, design, modeling and simulation, and comparison with experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Wicaksono, D H B [Department of Microelectronics, Delft University of Technology, Mekelweg 4, Delft, Zuid-Holland 2628CD (Netherlands); Zhang, L-J [Department of Microelectronics, Delft University of Technology, Mekelweg 4, Delft, Zuid-Holland 2628CD (Netherlands); Pandraud, G [Department of Microelectronics, Delft University of Technology, Mekelweg 4, Delft, Zuid-Holland 2628CD (Netherlands); French, P J [Department of Microelectronics, Delft University of Technology, Mekelweg 4, Delft, Zuid-Holland 2628CD (Netherlands); Vincent, J F V [Department of Mech. Engineering, Bath University Bath, BA2 7AY (United Kingdom)

    2006-04-01

    A new strain-sensing structure inspired from insect's (especially the Fly) propricoception sensor is devised. The campaniform sensillum is a strain-sensing microstructure with very high sensitivity despite its small dimension (diameter {approx}10 {mu}m in a relatively stiff material of insect's exocuticle (E = {approx}10{sup 9} Pa). Previous work shows that the high sensitivity of this structure towards strain is due to its membrane-in-recess- and strainconcentrating-hole-features. Based on this inspiration, we built similar structure using silicon micromachining technology. Then a simple characterisation setup was devised. Here, we present briefly, finite-element modeling and simulation based on this actual sample preparation for the characterisation. As comparison and also to understand mechanical features responsible for the strain-sensitivity, we performed the modeling on different mechanical structures: bulk chunk, blind-hole, through-hole, surface membrane, and membrane-in-recess. The actual experimental characterisation was performed previously using optical technique to membrane in-recess micromachined Si structure. The FEM simulation results confirm that the bending stress and strain are concentrated in the hole-vicinity. The membrane inside the hole acts as displacement transducer. The FEM is in conformity with previous analytical results, as well as the optical characterisation result. The end goal is to build a new type MEMS strain sensor.

  20. Used Nuclear Fuel Loading and Structural Performance Under Normal Conditions of Transport - Modeling, Simulation and Experimental Integration RD&D Plan

    Energy Technology Data Exchange (ETDEWEB)

    Adkins, Harold E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-04-01

    Under current U.S. Nuclear Regulatory Commission regulation, it is not sufficient for used nuclear fuel (UNF) to simply maintain its integrity during the storage period, it must maintain its integrity in such a way that it can withstand the physical forces of handling and transportation associated with restaging the fuel and moving it to treatment or recycling facilities, or a geologic repository. Hence it is necessary to understand the performance characteristics of aged UNF cladding and ancillary components under loadings stemming from transport initiatives. Researchers would like to demonstrate that enough information, including experimental support and modeling and simulation capabilities, exists to establish a preliminary determination of UNF structural performance under normal conditions of transport (NCT). This research, development and demonstration (RD&D) plan describes a methodology, including development and use of analytical models, to evaluate loading and associated mechanical responses of UNF rods and key structural components. This methodology will be used to provide a preliminary assessment of the performance characteristics of UNF cladding and ancillary components under rail-related NCT loading. The methodology couples modeling and simulation and experimental efforts currently under way within the Used Fuel Disposition Campaign (UFDC). The methodology will involve limited uncertainty quantification in the form of sensitivity evaluations focused around available fuel and ancillary fuel structure properties exclusively. The work includes collecting information via literature review, soliciting input/guidance from subject matter experts, performing computational analyses, planning experimental measurement and possible execution (depending on timing), and preparing a variety of supporting documents that will feed into and provide the basis for future initiatives. The methodology demonstration will focus on structural performance evaluation of

  1. Optimal Experimental Design for Model Discrimination

    Science.gov (United States)

    Myung, Jay I.; Pitt, Mark A.

    2009-01-01

    Models of a psychological process can be difficult to discriminate experimentally because it is not easy to determine the values of the critical design variables (e.g., presentation schedule, stimulus structure) that will be most informative in differentiating them. Recent developments in sampling-based search methods in statistics make it…

  2. PEMFC modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C. [Federal University of Parana (UFPR), Curitiba, PR (Brazil). Dept. of Mechanical Engineering], E-mail: jvargas@demec.ufpr.br; Ordonez, J.C.; Martins, L.S. [Florida State University, Tallahassee, FL (United States). Center for Advanced Power Systems], Emails: ordonez@caps.fsu.edu, martins@caps.fsu.edu

    2009-07-01

    In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes. (author)

  3. Structural system identification: Structural dynamics model validation

    Energy Technology Data Exchange (ETDEWEB)

    Red-Horse, J.R.

    1997-04-01

    Structural system identification is concerned with the development of systematic procedures and tools for developing predictive analytical models based on a physical structure`s dynamic response characteristics. It is a multidisciplinary process that involves the ability (1) to define high fidelity physics-based analysis models, (2) to acquire accurate test-derived information for physical specimens using diagnostic experiments, (3) to validate the numerical simulation model by reconciling differences that inevitably exist between the analysis model and the experimental data, and (4) to quantify uncertainties in the final system models and subsequent numerical simulations. The goal of this project was to develop structural system identification techniques and software suitable for both research and production applications in code and model validation.

  4. Topology, Structure and Functionality: Analysis, Modelling and Experimentation of Dense Granular Deformation in 2D and 3D

    Science.gov (United States)

    2015-01-05

    in a research position that will apply her skills at granular experiment and modeling to important issues related to pharmaceutical processing...photoelastic techniques was part of an overall exhibit at the Mueseum of Science and Industry in Chicago that received a Gold medal. • Since September...organized an international Pan-American scientific program on granular materials in La Plata, Argentina in August, 2014. • The PI is co-founder and

  5. Heat transfer between air and different structures of the Earth's surface monitored at an experimental model site

    Science.gov (United States)

    Dedecek, P.; Kresl, M.

    2003-04-01

    For correct interpretation of the last climatic changes, based on inversion of the temperature profile of deep boreholes, relationship between the soil and surface air temperatures must be taken in account. A continuous monitoring of the surface heat transfer on the campus of the Geophysical Institute in Prague has been under way since June 2002. A set of models of surface conditions, each model being 150 cm in diameter and 60 cm deep, incorporates grassy and barren clayey soil, sand and asphalt road. The underground temperature is registered in 5 levels below surface, the air temperature in 2 levels above surface. Soil moisture is measured in a separate model. Results of this observatory field are completed by precipitation data and underground temperatures from the hole GFU-1, drilled in Ordovican sediments with an uppermost layer of loam, some 150 meters apart. Contrary to the model site the horizon of which is free except a nonsignificant portion to the North, the GFU-1 hole is partially shaded by a deciduous tree. The obtained time-temperature series are used for speculation on soil and air temperature coupling, comparison of temperatures under different surfaces and determination of changes of diffusivity in individual materials caused by soil moisture changes. After a six months long operation of the experiment, we can present some results. It is evident, that in a sunny summer day, the asphalt will be warmer than other surfaces. In August, the average temperature 5 cm under the asphalt surface was higher by 7.5 K than under grassy soil. In the depth of 50 cm was the difference about 4 K. On the contrary, in December the grassy soil in 5 cm was warmer by 2.7 K, and in 50 cm by 0.9 K then asphalt. We tried also to calculate the thermal diffusivity from the temperature data. The values obtained well reflects the local conditions of the layer.

  6. Experimental investigations of the nuclear structure

    International Nuclear Information System (INIS)

    Gromov, K.Ya.

    1989-01-01

    The problem of experimental investigation into atomic nucleus structure is discussed. Examples of studying the properties of low-lying nucleus states using cyclotron-type accelerators for their production are presented. The consideration is conducted on the base of the Idisol experimental complex created at the Finland. Results of measuring masses of neutron-redundant rubidium nuclei are presented. Schemes of 160 Er and 108 In decay are presented. 12 refs.; 6 figs

  7. Experimental and computational study of thaumasite structure

    Energy Technology Data Exchange (ETDEWEB)

    Scholtzová, Eva, E-mail: Eva.Scholtzova@savba.sk [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava (Slovakia); Kucková, Lenka; Kožíšek, Jozef [Department of Physical Chemistry, Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava (Slovakia); Pálková, Helena [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava (Slovakia); Tunega, Daniel [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava (Slovakia); Institute for Soil Science, University of Natural Resources and Life Sciences, Peter-Jordanstrasse 82, A-1190 Wien (Austria)

    2014-05-01

    The structure of thaumasite has been studied experimentally by means of a single crystal X-ray diffraction and FTIR methods, and theoretically using density functional theory (DFT) method. Very good agreement was achieved between calculated and experimental structural parameters. In addition, calculations offered the refinement of the positions of the hydrogen atoms. The detailed analysis of the hydrogen bonds existing in the thaumasite structure has been performed. Several types of hydrogen bonds have been classified. The water molecules coordinating Ca{sup 2+} cation act as proton donors in moderate O-H···O hydrogen bonds formed with CO₃⁻²and SO₄⁻² anions. The multiple O-H···O hydrogen bonds exist among water molecules themselves. Finally, relatively weak hydrogen bonds form water molecules with the OH groups from the coordination sphere of the Si(OH)₆⁻² anion. Further, calculated vibrational spectrum allowed complete assignment of all vibrational modes which are not available from the experimental spectrum that has a complex structure with overlapped bands, especially below 1500 cm⁻¹. Highlights: • The thaumasite structure was studied experimentally and using DFT method. • We used DFT method for the refinement of the positions of hydrogen atoms. • A detailed analysis of the hydrogen bonds was done. • A complete assignment of all bands to particular types of vibrations was done.

  8. Severity of structural and functional right ventricular remodeling depends on training load in an experimental model of endurance exercise.

    Science.gov (United States)

    Sanz-de la Garza, Maria; Rubies, Cira; Batlle, Montserrat; Bijnens, Bart H; Mont, Lluis; Sitges, Marta; Guasch, Eduard

    2017-09-01

    Arrhythmogenic right ventricular (RV) remodeling has been reported in response to regular training, but it remains unclear how exercise intensity affects the presence and extent of such remodeling. We aimed to assess the relationship between RV remodeling and exercise load in a long-term endurance training model. Wistar rats were conditioned to run at moderate (MOD; 45 min, 30 cm/s) or intense (INT; 60 min, 60 cm/s) workloads for 16 wk; sedentary rats served as controls. Cardiac remodeling was assessed with standard echocardiographic and tissue Doppler techniques, sensor-tip pressure catheters, and pressure-volume loop analyses. After MOD training, both ventricles similarly dilated (~16%); the RV apical segment deformation, but not the basal segment deformation, was increased [apical strain rate (SR): -2.9 ± 0.5 vs. -3.3 ± 0.6 s -1 , SED vs. MOD]. INT training prompted marked RV dilatation (~26%) but did not further dilate the left ventricle (LV). A reduction in both RV segments' deformation in INT rats (apical SR: -3.3 ± 0.6 vs. -3.0 ± 0.4 s -1 and basal SR: -3.3 ± 0.7 vs. -2.7 ± 0.6 s -1 , MOD vs. INT) led to decreased global contractile function (maximal rate of rise of LV pressure: 2.53 ± 0.15 vs. 2.17 ± 0.116 mmHg/ms, MOD vs. INT). Echocardiography and hemodynamics consistently pointed to impaired RV diastolic function in INT rats. LV systolic and diastolic functions remained unchanged in all groups. In conclusion, we showed a biphasic, unbalanced RV remodeling response with increasing doses of exercise: physiological adaptation after MOD training turns adverse with INT training, involving disproportionate RV dilatation, decreased contractility, and impaired diastolic function. Our findings support the existence of an exercise load threshold beyond which cardiac remodeling becomes maladaptive. NEW & NOTEWORTHY Exercise promotes left ventricular eccentric hypertrophy with no changes in systolic or diastolic function in healthy rats. Conversely, right

  9. Masonry structures built with fictile tubules: Experimental and numerical analyses

    Science.gov (United States)

    Tiberti, Simone; Scuro, Carmelo; Codispoti, Rosamaria; Olivito, Renato S.; Milani, Gabriele

    2017-11-01

    Masonry structures with fictile tubules were a distinctive building technique of the Mediterranean area. This technique dates back to Roman and early Christian times, used to build vaulted constructions and domes with various geometrical forms by virtue of their modular structure. In the present work, experimental tests were carried out to identify the mechanical properties of hollow clay fictile tubules and a possible reinforcing technique for existing buildings employing such elements. The experimental results were then validated by devising and analyzing numerical models with the FE software Abaqus, also aimed at investigating the structural behavior of an arch via linear and nonlinear static analyses.

  10. Structural disorder model

    International Nuclear Information System (INIS)

    Dixit, P.K.; Vaid, B.A.; Sharma, K.C.

    1986-01-01

    The structure disorder model, recently proposed to explain the thermodynamic properties near the transition of first order, is generalized to include the pressure-induced transitions in tetrahedrally coordinated tin and A/sup N/B/sup 8-N/ compounds (with N = 2, 3). For Sn the calculated values of the change in thermodynamic quantities during the transition are found to be closer to the experimental values. For A/sup N/B/sup 8-N/ compounds, the transition is explained in a satisfactory manner in terms of partial ionic bonds and covalent bonds. The change in compressibility near the transition is found to be in agreement with that obtained from experiments. (author)

  11. Protective effect of transient receptor potential vanilloid subtype 1 (TRPV1) modulator, against behavioral, biochemical and structural damage in experimental models of Alzheimer's disease.

    Science.gov (United States)

    Jayant, Shalini; Sharma, B M; Sharma, Bhupesh

    2016-07-01

    Alzheime's disease (AD) is an overwhelming neurodegenerative disorder, characterized by synaptic dysfunction, memory loss, neuro-inflammation and neural cell death. Very few treatments are in hand for the management of AD and they are only concentrating on peculiar aspects. Hence, an immense thrust is required to find utmost therapeutic targets to conquer this condition. This study investigates a potential role of vanillin, a selective agonist of transient receptor potential vanilloid subtype 1 (TRPV1) in the experimental models of AD viz. intracerebroventricular (i.c.v.) streptozotocin (STZ) and aluminum trichloride (AlCl3)+d-galactose induced AD in mice. The i.c.v. administration of STZ and intraperitoneally administration of AlCl3+d-galactose have significantly impaired learning-memory (Morris water maze and attentional set-shifting test), brain structure (hematoxylin, eosin and Congo red staining), enhanced brain oxidative stress (thiobarbituric acid reactive substance - TBARS and glutathione - GSH), nitrosative stress (nitrite/nitrate), acetylcholinesterase activity (AChE), inflammation (MPO), and calcium levels (Ca(++)). Treatment with vanillin in different doses and donepezil have significantly ameliorated i.c.v. STZ and AlCl3+d-galactose induced reduction in executive function, impaired reversal learning, cognition, memory and brain damage. Treatment with these drugs has also reduced the brain oxidative stress (TBARS and GSH), nitrosative stress (nitrite/nitrate), and AChE, MPO, and Ca(++) levels. These results indicate that vanillin, a selective agonist of TRPV1 and donepezil, a potent acetylcholine esterase inhibitor have attenuated i.c.v. STZ and AlCl3+d-galactose induced experimental AD. Hence, pharmacological positive modulation of TRPV1 channels may be a potential research target for mitigation of AD. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Regularized Structural Equation Modeling

    Science.gov (United States)

    Jacobucci, Ross; Grimm, Kevin J.; McArdle, John J.

    2016-01-01

    A new method is proposed that extends the use of regularization in both lasso and ridge regression to structural equation models. The method is termed regularized structural equation modeling (RegSEM). RegSEM penalizes specific parameters in structural equation models, with the goal of creating easier to understand and simpler models. Although regularization has gained wide adoption in regression, very little has transferred to models with latent variables. By adding penalties to specific parameters in a structural equation model, researchers have a high level of flexibility in reducing model complexity, overcoming poor fitting models, and the creation of models that are more likely to generalize to new samples. The proposed method was evaluated through a simulation study, two illustrative examples involving a measurement model, and one empirical example involving the structural part of the model to demonstrate RegSEM’s utility. PMID:27398019

  13. Direct experimental determination of the atomic structure at internal interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Browning, N.D. [Oak Ridge National Lab., TN (United States)]|[Illinois Univ., Chicago, IL (United States); Pennycook, S.J. [Oak Ridge National Lab., TN (United States)

    1995-07-01

    A crucial first step in understanding the effect that internal interfaces have on the properties of materials is the ability to determine the atomic structure at the interface. As interfaces can contain atomic disorder, dislocations, segregated impurities and interphases, sensitivity to all of these features is essential for complete experimental characterization. By combining Z-contrast imaging and electron energy loss spectroscopy (EELS) in a dedicated scanning transmission electron microscope (STEM), the ability to probe the structure, bonding and composition at interfaces with the necessary atomic resolution has been obtained. Experimental conditions can be controlled to provide, simultaneously, both incoherent imaging and spectroscopy. This enables interface structures observed in the image to be interpreted intuitively and the bonding in a specified atomic column to be probed directly by EELS. The bonding and structure information can then be correlated using bond-valence sum analysis to produce structural models. This technique is demonstrated for 25{degrees}, 36{degrees} and 67{degrees} symmetric and 45{degrees} and 25{degrees} asymmetric [001] tilt grain boundaries in SrTiO{sub 3} The structures of both types of boundary were found to contain partially occupied columns in the boundary plane. From these experimental results, a series of structural units were identified which could be combined, using continuity of gain boundary structure principles, to construct all [001] tilt boundaries in SrTiO{sub 3}. Using these models, the ability of this technique to address the issues of vacancies and dopant segregation at grain boundaries in electroceramics is discussed.

  14. Automated Protein Structure Modeling with SWISS-MODEL Workspace and the Protein Model Portal

    OpenAIRE

    Bordoli, Lorenza; Schwede, Torsten

    2012-01-01

    Comparative protein structure modeling is a computational approach to build three-dimensional structural models for proteins using experimental structures of related protein family members as templates. Regular blind assessments of modeling accuracy have demonstrated that comparative protein structure modeling is currently the most reliable technique to model protein structures. Homology models are often sufficiently accurate to substitute for experimental structures in a wide variety of appl...

  15. Experimental investigation of bubble plume structure instability

    Energy Technology Data Exchange (ETDEWEB)

    Marco Simiano; Robert Zboray; Francois de Cachard [Thermal-Hydraulics Laboratory, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Djamel Lakehal; George Yadigaroglu [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH-Zentrum/CLT, 8092 Zurich (Switzerland)

    2005-07-01

    Full text of publication follows: The hydrodynamic properties of a 3D bubble plume in a large water pool are investigated experimentally. Bubble plumes are present in various industrial processes, including chemical plants, stirred reactors, and nuclear power plants, e.g. in BWR suppression pools. In these applications, the main issue is to predict the currents induced by the bubbles in the liquid phase, and to determine the consequent mixing. Bubble plumes, especially large and unconfined ones, present strong 3D effects and a superposition of different characteristic length scales. Thus, they represent relevant test cases for assessment and verification of 3D models in thermal-hydraulic codes. Bubble plumes are often unsteady, with fluctuations in size and shape of the bubble swarm, and global movements of the plume. In this case, local time-averaged data are not sufficient to characterize the flow. Additional information regarding changes in plume shape and position is required. The effect of scale on the 3D flow structure and stability being complex, there was a need to conduct studies in a fairly large facility, closer to industrial applications. Air bubble plumes, up to 30 cm in base diameter and 2 m in height were extensively studied in a 2 m diameter water pool. Homogeneously sized bubbles were obtained using a particular injector. The main hydrodynamic parameters. i.e., gas and liquid velocities, void fraction, bubble shape and size, plume shape and position, were determined experimentally. Photographic and image processing techniques were used to characterize the bubble shape, and double-tip optical probes to measure bubble size and void fraction. Electromagnetic probes measured the recirculation velocity in the pool. Simultaneous two-phase flow particle image velocimetry (STPFPIV) in a vertical plane containing the vessel axis provided instantaneous velocity fields for both phases and therefore the relative velocity field. Video recording using two CCD

  16. 3D QSAR studies for the beta-tubulin binding site of microtubule-stabilizing anticancer agents (MSAAs): a pseudoreceptor model for taxanes based on the experimental structure of tubulin.

    Science.gov (United States)

    Maccari, Laura; Manetti, Fabrizio; Corelli, Federico; Botta, Maurizio

    2003-09-01

    The antimitotic agent paclitaxel continues to play an important role in the cancer chemotherapy. However, its inefficacy on certain resistant cells and toxic side effects have led to the search of new taxanes with improved biological activity. By means of a pseudoreceptor modeling approach, we have developed a binding site model for a series of taxanes. It is the first 3D QSAR model derived from the experimentally determined tubulin structure obtained by electron crystallography studies. The model is able to correlate quantitatively the structural properties of the studied compounds with their biological data.

  17. Modeling Fluid Structure Interaction

    National Research Council Canada - National Science Library

    Benaroya, Haym

    2000-01-01

    The principal goal of this program is on integrating experiments with analytical modeling to develop physics-based reduced-order analytical models of nonlinear fluid-structure interactions in articulated naval platforms...

  18. Uncertainty Quantification in Experimental Structural Dynamics Identification of Composite Material Structures

    DEFF Research Database (Denmark)

    Luczak, Marcin; Peeters, Bart; Kahsin, Maciej

    2014-01-01

    Aerospace and wind energy structures are extensively using components made of composite materials. Since these structures are subjected to dynamic environments with time-varying loading conditions, it is important to model their dynamic behavior and validate these models by means of vibration...... for uncertainty evaluation in experimentally estimated models. Investigated structures are plates, fuselage panels and helicopter main rotor blades as they represent different complexity levels ranging from coupon, through sub-component up to fully assembled structures made of composite materials. To evaluate...

  19. Experimental study of the nucleon spin structure

    International Nuclear Information System (INIS)

    Litmaath, M.F.

    1996-01-01

    After introducing the theoretical framework, which includes DIS, the Quark Parton Model (QPM) and QCD, we describe the implementation of the experiment. The SMC uses a beam of 190 GeV naturally polarized muons, scattering off nucleons in a large cryogenic target containing protons or deuterons that are polarized through Dynamic Nuclear Polarization (DNP). The target material is located in two cells in a row, with opposite polarizations. Every 5 hours the polarizations of both cells are reversed. The target polarization is measured by an NMR system. The polarization of the beam is measured in a polarimeter, located downstream of the main experimental setup. (orig.)

  20. Experimental "evolutional machines": mathematical and experimental modeling of biological evolution

    Science.gov (United States)

    Brilkov, A. V.; Loginov, I. A.; Morozova, E. V.; Shuvaev, A. N.; Pechurkin, N. S.

    Experimentalists possess model systems of two major types for study of evolution continuous cultivation in the chemostat and long-term development in closed laboratory microecosystems with several trophic structure If evolutionary changes or transfer from one steady state to another in the result of changing qualitative properties of the system take place in such systems the main characteristics of these evolution steps can be measured By now this has not been realized from the point of view of methodology though a lot of data on the work of both types of evolutionary machines has been collected In our experiments with long-term continuous cultivation we used the bacterial strains containing in plasmids the cloned genes of bioluminescence and green fluorescent protein which expression level can be easily changed and controlled In spite of the apparent kinetic diversity of evolutionary transfers in two types of systems the general mechanisms characterizing the increase of used energy flow by populations of primer producent can be revealed at their study According to the energy approach at spontaneous transfer from one steady state to another e g in the process of microevolution competition or selection heat dissipation characterizing the rate of entropy growth should increase rather then decrease or maintain steady as usually believed The results of our observations of experimental evolution require further development of thermodynamic theory of open and closed biological systems and further study of general mechanisms of biological

  1. Experimental Data in Vehicle Modeling

    Directory of Open Access Journals (Sweden)

    Tomasikova Maria

    2017-05-01

    Full Text Available This article is about a vehicle model which is created in software Matlab Simscape Driveline. In this model the motor is created like a subsystem by Simulink blocks and input data were measured by single roller dynamometer for cars (SRD. Measured data are the input into the model by Lookup Table block. The vehicle model is made by gear, differential, tire and vehicle body blocks. We studied the forces on tires, the vehicle velocity and the slip.

  2. Bridge-in-a-backpack(TM) : task 3.2: investigating soil - structure interaction - modeling and experimental results of steel arches.

    Science.gov (United States)

    2015-07-01

    This report includes fulfillment of Task 3.2 of a multi-task contract to further enhance concrete filled FRP tubes, or : the Bridge in a Backpack. Task 3 is an investigation of soil-structure interaction for the FRP tubes. Task 3.2 is the : modeling ...

  3. Bridge-in-a-backpack(TM) task 3.3 : investigate soil-structure interaction-modeling and experimental results of concrete filled FRP tube arches.

    Science.gov (United States)

    2015-12-01

    This report includes fulfillment of Task 3.3 of a multi-task contract to further enhance concrete filled FRP tubes, or : the Bridge in a Backpack. Task 3 is an investigation of soil-structure interaction for the FRP tubes. Task 3.3 is the : modeling ...

  4. Structural Equation Model Trees

    Science.gov (United States)

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  5. Structural Equation Model Trees

    Science.gov (United States)

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2015-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree structures that separate a data set recursively into subsets with significantly different parameter estimates in a SEM. SEM Trees provide means for finding covariates and covariate interactions that predict differences in structural parameters in observed as well as in latent space and facilitate theory-guided exploration of empirical data. We describe the methodology, discuss theoretical and practical implications, and demonstrate applications to a factor model and a linear growth curve model. PMID:22984789

  6. ROSACE, an experimentally based model

    International Nuclear Information System (INIS)

    Gatesoupe, J.P.

    1979-01-01

    The ROSACE code was mainly developed to evaluate the sensitivity of fuel thermal performances for designing parameters such as geometry, density, etc. Such a code has not to been able to give an a priori entirely reliable description of fuel behaviour under any circumstances. The best that can be satisfactory is a thorough special calibration of the code within the restricted area of any specific investigation. That is the reason for the rather light structure built for the ROSACE code which is described in some detail

  7. An experimental study on soil-structure interaction effects

    International Nuclear Information System (INIS)

    Mita, Akira; Kumagai, Shigeru

    1989-01-01

    The soil-structure interaction effects play an important role in the earthquake response of large scale structures such as nuclear power plants. Recent decades, many experimental and analytical studies have been conducted. Even though sophisticated analytical tools are ready to use, complicated soil-structure interaction problems such as those with a complex geometry can not be solved yet. For such problems a laboratory experiment is a powerful alternative. In the laboratory experiment, a device to absorb the reflected waves is always necessary to be attached on the boundaries of the soil model to simulate the semi-infiniteness of the actual ground. But unfortunately absorbing devices currently available are far from satisfactory. In this paper, a new experimental method is employed for soil-structure interaction problems to simulate the semi-infiniteness of the actual ground. The present method utilizes the characteristics of transient response to an impulse load so that no special treatment on the boundaries of the soil model is required. This technique is applicable to a linear elastic system whose impulse response decreases to a small enough value before observing the reflected waves. (author)

  8. Global Structural Flexibility of Metalloproteins Regulates Reactivity of Transition Metal Ion in the Protein Core: An Experimental Study Using Thiol-subtilisin as a Model Protein.

    Science.gov (United States)

    Matsuo, Takashi; Kono, Takamasa; Shobu, Isamu; Ishida, Masaya; Gonda, Katsuya; Hirota, Shun

    2018-02-21

    The functions of metal-containing proteins (metalloproteins) are determined by the reactivities of transition metal ions at their active sites. Because protein macromolecular structures have several molecular degrees of freedom, global structural flexibility may also regulate the properties of metalloproteins. However, the influence of this factor has not been fully delineated in mechanistic studies of metalloproteins. Accordingly, we have investigated the relationship between global protein flexibility and the characteristics of a transition metal ion in the protein core using thiol-subtilisin (tSTL) with a Cys-coordinated Cu 2+ ion as a model system. Although tSTL has two Ca 2+ -binding sites, the Ca 2+ -binding status hardly affects its secondary structure. Nevertheless, guanidinium-induced denaturation and amide H/D exchange indicated the increase in the structural flexibility of tSTL by the removal of bound Ca 2+ ions. Electron paramagnetic resonance and absorption spectral changes have revealed that the protein flexibility determines the characteristics of a Cu 2+ ion in tSTL. Therefore, global protein flexibility should be recognized as an important factor that regulates the properties of metalloproteins. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Experimental models of demyelination and remyelination.

    Science.gov (United States)

    Torre-Fuentes, L; Moreno-Jiménez, L; Pytel, V; Matías-Guiu, J A; Gómez-Pinedo, U; Matías-Guiu, J

    2017-08-29

    Experimental animal models constitute a useful tool to deepen our knowledge of central nervous system disorders. In the case of multiple sclerosis, however, there is no such specific model able to provide an overview of the disease; multiple models covering the different pathophysiological features of the disease are therefore necessary. We reviewed the different in vitro and in vivo experimental models used in multiple sclerosis research. Concerning in vitro models, we analysed cell cultures and slice models. As for in vivo models, we examined such models of autoimmunity and inflammation as experimental allergic encephalitis in different animals and virus-induced demyelinating diseases. Furthermore, we analysed models of demyelination and remyelination, including chemical lesions caused by cuprizone, lysolecithin, and ethidium bromide; zebrafish; and transgenic models. Experimental models provide a deeper understanding of the different pathogenic mechanisms involved in multiple sclerosis. Choosing one model or another depends on the specific aims of the study. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. A porous medium approach for the fluid structure interaction modelling of a water pressurized nuclear reactor core fuel assemblies: simulation and experimentation; Une approche milieu poreux pour la modeisation de l'interaction fluide-structure des assemblages combustibles dans un coeur de reacteur a eau pressurisee: simulation et experimentation

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, G.

    2008-10-15

    The designing of a pressurized water reactor core subjected to seismic loading, is a major concern of the nuclear industry. We propose, in this PhD report, to establish the global behaviour equations of the core, in term of a porous medium. Local equations of fluid and structure are space averaged on a control volume, thus we define an equivalent fluid and an equivalent structure, of which unknowns are defined on the whole space. The non-linear fuel assemblies behaviour is modelled by a visco-elastic constitutive law. The fluid-structure coupling is accounted for by a body force, the expression of that force is based on empirical formula of fluid forces acting on a tube subject to an axial flow. The resulting equations are solved using a finite element method. A validation of the model, on three experimental device, is proposed. The first one presents two fuel assemblies subjected to axial flow. One of the two fuel assemblies is deviated from its position of equilibrium and released, while the other is at rest. The second one presents a six assemblies row, immersed in water, placed on a shaking table that can simulate seismic loading. Finally, the last one presents nine fuel assemblies network, arranged in a three by three, subject to an axial flow. The displacement of the central fuel assembly is imposed. The simulations are in agreement with the experiments, the model reproduces the influence of the flow of fluid on the dynamics and coupling of the fuel assemblies. (author)

  11. Experimental Study of the Composition and Structure of Granular Media in the Shear Bands Based on the HHC-Granular Model

    Directory of Open Access Journals (Sweden)

    Guang-jin Wang

    2014-01-01

    Full Text Available The researchers cannot control the composition and structure of coarse grained soil in the indoor experiment because the granular particles of different size have the characteristics of random distribution and no sorting. Therefore, on the basis of the laboratory tests with the coarse grained soil, the HHC-Granular model, which could simulate the no sorting and random distribution of different size particles in the coarse-grained soil, was developed by use of cellular automata method. Meanwhile, the triaxial numerical simulation experiments of coarse grained soil were finished with the different composition and structure soil, and the variation of shear strength was discussed. The results showed that the internal friction angle was likely to reduce with the increasing of gravel contents in the coarse-grained soil, but the mean internal friction angle significantly increased with the increment of gravel contents. It indicated that the gravel contents of shear bands were the major factor affecting the shear strength.

  12. Towards an optimal experimental design for N2O model calibration during biological nitrogen removal

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Valverde Pérez, Borja; Plósz, Benedek G.

    substrates. Improving experimental designs for model calibration reduces prediction uncertainties. Moreover, the individual analysis of autotrophic and heterotrophic contribution to the total NO and N2O pool was assessed for already proposed model structures under different experimental scenarios...

  13. Automated protein structure modeling with SWISS-MODEL Workspace and the Protein Model Portal.

    Science.gov (United States)

    Bordoli, Lorenza; Schwede, Torsten

    2012-01-01

    Comparative protein structure modeling is a computational approach to build three-dimensional structural models for proteins using experimental structures of related protein family members as templates. Regular blind assessments of modeling accuracy have demonstrated that comparative protein structure modeling is currently the most reliable technique to model protein structures. Homology models are often sufficiently accurate to substitute for experimental structures in a wide variety of applications. Since the usefulness of a model for specific application is determined by its accuracy, model quality estimation is an essential component of protein structure prediction. Comparative protein modeling has become a routine approach in many areas of life science research since fully automated modeling systems allow also nonexperts to build reliable models. In this chapter, we describe practical approaches for automated protein structure modeling with SWISS-MODEL Workspace and the Protein Model Portal.

  14. Improving the physiological realism of experimental models.

    Science.gov (United States)

    Vinnakota, Kalyan C; Cha, Chae Y; Rorsman, Patrik; Balaban, Robert S; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A; Jeneson, Jeroen A L

    2016-04-06

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these models rely on the analysis and integration of experimental data. As such, the success of VPH depends on the availability of physiologically realistic experimental models (E-Models) of human organ function that can be parametrized to test the numerical models. Here, the current state of suitable E-models, ranging from in vitro non-human cell organelles to in vivo human organ systems, is discussed. Specifically, challenges and recent progress in improving the physiological realism of E-models that may benefit the VPH project are highlighted and discussed using examples from the field of research on cardiovascular disease, musculoskeletal disorders, diabetes and Parkinson's disease.

  15. Experimental/Numerical Comparison of Turbine Efficiency and Wake Structure in an Array of 3 Scale-Model Marine Hydrokinetic Turbines

    Science.gov (United States)

    Sale, Danny; Bates, John; Polagye, Brian; Aliseda, Alberto

    2015-11-01

    Numerical simulations and experiments are conducted for axial-flow Marine Hydro-Kinetic (MHK) turbines operating in a flume. This study aims to understand the influence of coherent structures in high Reynolds number wakes on energy extraction and dynamical rotor control processes. In experiments, rotor torque and rotational position measurements are collected, and the flow field characterized by simultaneous imaging with particle image velocimetry. The performance of 3 turbines are characterized under varying downstream spacing and lateral offsets. To study effects of unsteady hydrodynamics, the turbines are outfitted with open-loop and close-loop feedback controls and compared to the case of uncontrolled rotor. In numerical simulations, different tiers of turbine models are evaluated to discern tradeoffs in fidelity to physics versus cost. Analogous ``actuator methods'' are included from Large-Eddy-Simulations and Reynolds-Averaged-Navier-Stokes, where the models impose body forces upon the flow field in form of disks, lines, or surfaces. An aeroelastic model coupled to LES predicts the dynamical response of rotors to upstream wakes and ambient turbulence. These comparative studies inform how simulations can be scaled up to inform design of utility-scale MHK power plants.

  16. Understanding Leadership: An Experimental-Experiential Model

    Science.gov (United States)

    Hole, George T.

    2014-01-01

    Books about leadership are dangerous to readers who fantasize about being leaders or apply leadership ideas as if they were proven formulas. As an antidote, I offer an experimental framework in which any leadership-management model can be tested to gain experiential understanding of the model. As a result one can gain reality-based insights about…

  17. EXPERIMENTAL MODEL OF INFESTATION IN OVINE OESTROSIS

    Directory of Open Access Journals (Sweden)

    DANIELA MOŢ

    2007-10-01

    Full Text Available The experimental model was been performed on 20 youth sheep, between 10-11months aged who were divided in two groups. The first group (10 animals containsonly healthy animals and represented the control group. The second group(experimental contains experimental infested animals with Oestrus ovis larvae, offirst stadium of evolution. Each sheep was been inoculated with 30 larvae onintranasal way. After three months from experimental infestation, the animals werebeen slaughtered and was made the necropsy. Were evaluated themorphopathological alterations and were been discovered the Oestrus ovis larvae.From the inoculated larvae 3 months ago were been founded 57.66 %. From these,16 % were on I stadium, 37.33 % II stadium and 4.33 % III stadium of evolution. Noclinical evident sign was observed in experimental infested sheep. This fact is inconcordance with other researchers observations, who demonstrated that theclinical reproduction of disease can be obtain only after 3-4 experimentaladministrations of Oestrus ovis larvae.

  18. Experimental Analysis and Mathematical Modeling on Mg-Li Alloy Sheets with Three Crystal Structures during Cold Rolling and Heat Treatment.

    Science.gov (United States)

    Tang, Yan; Le, Qichi; Wang, Tong; Chen, Xingrui

    2017-10-12

    The microstructural evolution, mechanical properties, and mathematical relationship of an α, α + β, and β phase Mg-Li alloy during the cold rolling and annealing process were investigated. The results showed that the increased Li element gradually transformed the Mg matrix structure from hcp to bcc. Simultaneously, the alloy plasticity was improved remarkably during cold rolling. In the annealing process, a sort of abnormal grain growth was found in Mg-11Li-3Al-2Zn-0.2Y, but was not detected in Mg-5Li-3Al-2Zn-0.2Y and Mg-8Li-3Al-2Zn-0.2Y. Moreover, the mechanical properties of alloy were evidently improved through a kind of solid solution in the β matrix. To accurately quantify this strengthening effect, the method of mathematical modeling was used to determine the relationship between strength and multiple factors.

  19. Biokinetic models for radionuclides in experimental animals

    International Nuclear Information System (INIS)

    Morcillo, M. A.

    2003-01-01

    The biokinetic models for many radionuclides are, to a large extent, based on data obtained in experimental animals. The methods used in the experimental development of a biokinetic model can be classified in two groups (i) those applied during the experimental work, which include the activity determination of a given radionuclide at different times and in different biological media such as blood, serum, organs/tissues, urine, bile and faeces and (ii) those methods used for the analysis and study of the experimental data, based in mathematical tools. Some of these methods are reviewed,with special emphasis in the whole body macro autoradiography. To conclude, the contribution that this type of studies can have in two fields of radiation protection is discussed, namely optimization of dosimetric evaluations and decorporation of radionuclides. (Author)

  20. ECONGAS - model structure

    International Nuclear Information System (INIS)

    1997-01-01

    This report documents a numerical simulation model of the natural gas market in Germany, France, the Netherlands and Belgium. It is a part of a project called ''Internationalization and structural change in the gas market'' aiming to enhance the understanding of the factors behind the current and upcoming changes in the European gas market, especially the downstream part of the gas chain. The model takes European border prices of gas as given, adds transmission and distribution cost and profit margins as well as gas taxes to calculate gas prices. The model includes demand sub-models for households, chemical industry, other industry, the commercial sector and electricity generation. Demand responses to price changes are assumed to take time, and the long run effects are significantly larger than the short run effects. For the household sector and the electricity sector, the dynamics are modeled by distinguishing between energy use in the old and new capital stock. In addition to prices and the activity level (GDP), the model includes the extension of the gas network as a potentially important variable in explaining the development of gas demand. The properties of numerical simulation models are often described by dynamic multipliers, which describe the behaviour of important variables when key explanatory variables are changed. At the end, the report shows the results of a model experiment where the costs in transmission and distribution were reduced. 6 refs., 9 figs., 1 tab

  1. ECONGAS - model structure

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This report documents a numerical simulation model of the natural gas market in Germany, France, the Netherlands and Belgium. It is a part of a project called ``Internationalization and structural change in the gas market`` aiming to enhance the understanding of the factors behind the current and upcoming changes in the European gas market, especially the downstream part of the gas chain. The model takes European border prices of gas as given, adds transmission and distribution cost and profit margins as well as gas taxes to calculate gas prices. The model includes demand sub-models for households, chemical industry, other industry, the commercial sector and electricity generation. Demand responses to price changes are assumed to take time, and the long run effects are significantly larger than the short run effects. For the household sector and the electricity sector, the dynamics are modeled by distinguishing between energy use in the old and new capital stock. In addition to prices and the activity level (GDP), the model includes the extension of the gas network as a potentially important variable in explaining the development of gas demand. The properties of numerical simulation models are often described by dynamic multipliers, which describe the behaviour of important variables when key explanatory variables are changed. At the end, the report shows the results of a model experiment where the costs in transmission and distribution were reduced. 6 refs., 9 figs., 1 tab.

  2. CCDC 1416891: Experimental Crystal Structure Determination : Methyl-triphenyl-germanium

    KAUST Repository

    Bernatowicz, Piotr

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. CCDC 1408042: Experimental Crystal Structure Determination : 6,13-dimesitylpentacene

    KAUST Repository

    Shi, Xueliang

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  4. Effect of policosanol on experimental thrombosis models.

    Science.gov (United States)

    Carbajal, D; Arruzazabala, M L; Más, R; Molina, V; Valdés, S

    1994-05-01

    Policosanol is a natural product, obtained from sugar cane wax (Saccharum officinarum L.) with which cholesterol-lowering effects have been demonstrated in experimental models, healthy volunteers and hypercholesterolemic patients. The effects of policosanol on experimental venous and arterial thrombosis in rats were investigated. Policosanol (25 mg/kg) significantly decreased the thrombus weight, in the venous thrombosis models, the protective effect persisting until 4 h after its oral administration. Policosanol (25 mg/kg single dose) was able to reduce rectal temperature variation induced by arterial thrombosis. Also at the same dose policosanol increased 6-keto-PGF1 alpha serum levels in rats.

  5. Building a Structural Model: Parameterization and Structurality

    Directory of Open Access Journals (Sweden)

    Michel Mouchart

    2016-04-01

    Full Text Available A specific concept of structural model is used as a background for discussing the structurality of its parameterization. Conditions for a structural model to be also causal are examined. Difficulties and pitfalls arising from the parameterization are analyzed. In particular, pitfalls when considering alternative parameterizations of a same model are shown to have lead to ungrounded conclusions in the literature. Discussions of observationally equivalent models related to different economic mechanisms are used to make clear the connection between an economically meaningful parameterization and an economically meaningful decomposition of a complex model. The design of economic policy is used for drawing some practical implications of the proposed analysis.

  6. Modeling protein structures: construction and their applications.

    Science.gov (United States)

    Ring, C S; Cohen, F E

    1993-06-01

    Although no general solution to the protein folding problem exists, the three-dimensional structures of proteins are being successfully predicted when experimentally derived constraints are used in conjunction with heuristic methods. In the case of interleukin-4, mutagenesis data and CD spectroscopy were instrumental in the accurate assignment of secondary structure. In addition, the tertiary structure was highly constrained by six cysteines separated by many residues that formed three disulfide bridges. Although the correct structure was a member of a short list of plausible structures, the "best" structure was the topological enantiomer of the experimentally determined conformation. For many proteases, other experimentally derived structures can be used as templates to identify the secondary structure elements. In a procedure called modeling by homology, the structure of a known protein is used as a scaffold to predict the structure of another related protein. This method has been used to model a serine and a cysteine protease that are important in the schistosome and malarial life cycles, respectively. The model structures were then used to identify putative small molecule enzyme inhibitors computationally. Experiments confirm that some of these nonpeptidic compounds are active at concentrations of less than 10 microM.

  7. Prospects of experimentally reachable beyond Standard Model ...

    Indian Academy of Sciences (India)

    2016-01-06

    Jan 6, 2016 ... Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 2. Prospects of experimentally reachable beyond Standard Model physics in inverse see-saw motivated SO(10) GUT. Ram Lal Awasthi. Special: Supersymmetric Unified Theories and Higgs Physics Volume 86 Issue 2 February 2016 pp 223- ...

  8. Prospects of experimentally reachable beyond Standard Model ...

    Indian Academy of Sciences (India)

    2016-01-06

    Jan 6, 2016 ... Dirac mass MH = ±M + μS/2. As μS does not play much role in any other prediction, we assume that it fits the neutrino oscillation data and one can determine it by inverting the inverse see-saw formula and using experimental results of neutrino masses and mixings. The model achieves precision gauge ...

  9. Electrochemical desalination of bricks - Experimental and modeling

    DEFF Research Database (Denmark)

    Skibsted, Gry; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2015-01-01

    Chlorides, nitrates and sulfates play an important role in the salt-decay of porous materials in buildings and monuments. Electrochemical desalination is a technology able to remove salts from such porous materials in order to stop or prevent the decay. In this paper, experimental and numerical......-contaminated bricks with respect to the monovalent ions is discussed. Comparison between the experimental and the simulation results showed that the proposed numerical model is able to predict electrochemical desalination treatments with remarkable accuracy, and it can be used as a predictive tool...

  10. Review of experimental models: sinusitis in rabbits

    Directory of Open Access Journals (Sweden)

    André Coura Perez

    2014-10-01

    Full Text Available INTRODUCTION: In order to better understand the pathophysiology of rhinosinusitis, several attempts have been made to create the disease in an animal model. Among the studied rodents each has its advantages and disadvantages. Rabbits are considered more appropriate for studies that require surgical manipulation or invasive procedures. OBJECTIVES: To evaluate the most viable experimental model of rhinosinusitis in rabbits to be adopted in future studies. METHODS: An electronic search for studies with experimental models of rhinosinusitis in rabbits published in English and Portuguese between July of 1967 and January of 2013 was conducted in Medline, Pub Med, Cochrane, and CAPES databases, using the keywords "sinusitis", "rabbits", and "polyps". RESULTS: A total of 256 studies were retrieved, but in accordance with the inclusion and exclusion criteria, only ten studies were selected. Many different methods of response assessment were used in these studies. CONCLUSION: To date, there is no ideal experimental model for induction of acute or chronic rhinosinusitis in rabbits, but the rhinogenic model appears to be the most viable option for the continuity of studies of the disease.

  11. [Review of experimental models: sinusitis in rabbits].

    Science.gov (United States)

    Perez, André Coura; Buzatto, Guilherme Pietrucci; Dantas, Ivan de Picole; Dorgam, João Vicente; Valera, Fabiana Cardoso Pereira; Tamashiro, Edwin; Lima, Wilma Terezinha Anselmo

    2014-01-01

    In order to better understand the pathophysiology of rhinosinusitis, several attempts have been made to create the disease in an animal model. Among the studied rodents each has its advantages and disadvantages. Rabbits are considered more appropriate for studies that require surgical manipulation or invasive procedures. To evaluate the most viable experimental model of rhinosinusitis in rabbits to be adopted in future studies. An electronic search for studies with experimental models of rhinosinusitis in rabbits published in English and Portuguese between July of 1967 and January of 2013 was conducted in Medline, Pub Med, Cochrane, and CAPES databases, using the keywords "sinusitis", "rabbits", and "polyps". A total of 256 studies were retrieved, but in accordance with the inclusion and exclusion criteria, only ten studies were selected. Many different methods of response assessment were used in these studies. To date, there is no ideal experimental model for induction of acute or chronic rhinosinusitis in rabbits, but the rhinogenic model appears to be the most viable option for the continuity of studies of the disease. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  12. The effect of the particle shape and structure on the flowability of electrolytic copper powder. II. The experimental verification of the model of the representative powder particle

    Directory of Open Access Journals (Sweden)

    MILUTIN C. OBRADOVIC

    2003-10-01

    Full Text Available An analysis of the effects of the shape, surface structure and size distribution of particles on the flowability of the copper powder was performed. It is shown that the most important property of the particles of a powder, regarding the flowability of the powder, is the surface structure of the particles.

  13. Irradiation Design for an Experimental Murine Model

    International Nuclear Information System (INIS)

    Ballesteros-Zebadua, P.; Moreno-Jimenez, S.; Suarez-Campos, J. E.; Celis, M. A.; Larraga-Gutierrez, J. M.; Garcia-Garduno, O. A.; Rubio-Osornio, M. C.; Custodio-Ramirez, V.; Paz, C.

    2010-01-01

    In radiotherapy and stereotactic radiosurgery, small animal experimental models are frequently used, since there are still a lot of unsolved questions about the biological and biochemical effects of ionizing radiation. This work presents a method for small-animal brain radiotherapy compatible with a dedicated 6MV Linac. This rodent model is focused on the research of the inflammatory effects produced by ionizing radiation in the brain. In this work comparisons between Pencil Beam and Monte Carlo techniques, were used in order to evaluate accuracy of the calculated dose using a commercial planning system. Challenges in this murine model are discussed.

  14. Linear causal modeling with structural equations

    CERN Document Server

    Mulaik, Stanley A

    2009-01-01

    Emphasizing causation as a functional relationship between variables that describe objects, Linear Causal Modeling with Structural Equations integrates a general philosophical theory of causation with structural equation modeling (SEM) that concerns the special case of linear causal relations. In addition to describing how the functional relation concept may be generalized to treat probabilistic causation, the book reviews historical treatments of causation and explores recent developments in experimental psychology on studies of the perception of causation. It looks at how to perceive causal

  15. Experimental Validation of a Dynamic Model for Lightweight Robots

    Directory of Open Access Journals (Sweden)

    Alessandro Gasparetto

    2013-03-01

    Full Text Available Nowadays, one of the main topics in robotics research is dynamic performance improvement by means of a lightening of the overall system structure. The effective motion and control of these lightweight robotic systems occurs with the use of suitable motion planning and control process. In order to do so, model-based approaches can be adopted by exploiting accurate dynamic models that take into account the inertial and elastic terms that are usually neglected in a heavy rigid link configuration. In this paper, an effective method for modelling spatial lightweight industrial robots based on an Equivalent Rigid Link System approach is considered from an experimental validation perspective. A dynamic simulator implementing the formulation is used and an experimental test-bench is set-up. Experimental tests are carried out with a benchmark L-shape mechanism.

  16. Model techniques for testing heated concrete structures

    International Nuclear Information System (INIS)

    Stefanou, G.D.

    1983-01-01

    Experimental techniques are described which may be used in the laboratory to measure strains of model concrete structures representing to scale actual structures of any shape or geometry, operating at elevated temperatures, for which time-dependent creep and shrinkage strains are dominant. These strains could be used to assess the distribution of stress in the scaled structure and hence to predict the actual behaviour of concrete structures used in nuclear power stations. Similar techniques have been employed in an investigation to measure elastic, thermal, creep and shrinkage strains in heated concrete models representing to scale parts of prestressed concrete pressure vessels for nuclear reactors. (author)

  17. Experimental Verification of the Buckling Strength of Structural Glass Columns

    OpenAIRE

    Pešek, Ondřej; Horáček, Martin; Melcher, Jindřich

    2016-01-01

    This paper deals with experimental research of axially loaded members made of structural (laminated) glass. The purpose of the research is the evaluation of buckling strength and actual behaviour of the columns due to the absence of standards for design of glass load-bearing structures. The experimental research follows the previous one focusing on measuring of initial geometrical imperfections of glass members. Within the frame of the research 15 specimens were tested. All of them were of th...

  18. Ischemic postconditioning: experimental models and protocol algorithms.

    Science.gov (United States)

    Skyschally, Andreas; van Caster, Patrick; Iliodromitis, Efstathios K; Schulz, Rainer; Kremastinos, Dimitrios T; Heusch, Gerd

    2009-09-01

    Ischemic postconditioning, a simple mechanical maneuver at the onset of reperfusion, reduces infarct size after ischemia/reperfusion. After its first description in 2003 by Zhao et al. numerous experimental studies have investigated this protective phenomenon. Whereas the underlying mechanisms and signal transduction are not yet understood in detail, infarct size reduction by ischemic postconditioning was confirmed in all species tested so far, including man. We have now reviewed the literature with focus on experimental models and protocols to better understand the determinants of protection by ischemic postconditioning or lack of it. Only studies with infarct size as unequivocal endpoint were considered. In all species and models, the duration of index ischemia and the protective protocol algorithm impact on the outcome of ischemic postconditioning, and gender, age, and myocardial temperature contribute.

  19. Linking Experimental Characterization and Computational Modeling in Microstructural Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, Melik Cumhar [Univ. of Pittsburgh, PA (United States)

    2002-06-01

    It is known that by controlling microstructural development, desirable properties of materials can be achieved. The main objective of our research is to understand and control interface dominated material properties, and finally, to verify experimental results with computer simulations. In order to accomplish this objective, we studied the grain growth in detail with experimental techniques and computational simulations. We obtained 5170-grain data from an Aluminum-film (120μm thick) with a columnar grain structure from the Electron Backscattered Diffraction (EBSD) measurements. Experimentally obtained starting microstructure and grain boundary properties are input for the three-dimensional grain growth simulation. In the computational model, minimization of the interface energy is the driving force for the grain boundary motion. The computed evolved microstructure is compared with the final experimental microstructure, after annealing at 550 ºC. Two different measures were introduced as methods of comparing experimental and computed microstructures. Modeling with anisotropic mobility explains a significant amount of mismatch between experiment and isotropic modeling. We have shown that isotropic modeling has very little predictive value. Microstructural evolution in columnar Aluminum foils can be correctly modeled with anisotropic parameters. We observed a strong similarity between grain growth experiments and anisotropic three-dimensional simulations.

  20. Linking Experimental Characterization and Computational Modeling in Microstructural Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, Melik Cumhur [Univ. of California, Berkeley, CA (United States)

    2002-06-01

    It is known that by controlling microstructural development, desirable properties of materials can be achieved. The main objective of our research is to understand and control interface dominated material properties, and finally, to verify experimental results with computer simulations. In order to accomplish this objective, we studied the grain growth in detail with experimental techniques and computational simulations. We obtained 5170-grain data from an Aluminum-film (120μm thick) with a columnar grain structure from the Electron Backscattered Diffraction (EBSD) measurements. Experimentally obtained starting microstructure and grain boundary properties are input for the three-dimensional grain growth simulation. In the computational model, minimization of the interface energy is the driving force for the grain boundary motion. The computed evolved microstructure is compared with the final experimental microstructure, after annealing at 550 ºC. Two different measures were introduced as methods of comparing experimental and computed microstructures. Modeling with anisotropic mobility explains a significant amount of mismatch between experiment and isotropic modeling. We have shown that isotropic modeling has very little predictive value. Microstructural evolution in columnar Aluminum foils can be correctly modeled with anisotropic parameters. We observed a strong similarity

  1. Integrated materials–structural models

    DEFF Research Database (Denmark)

    Stang, Henrik; Geiker, Mette Rica

    2008-01-01

    of structural modelling and materials concepts will both operational in both identifying important research issues and in answering the ‘real’ needs of society. Integrated materials-structural models will allow synergy to develop between materials and structural research. On one side the structural modelling......Reliable service life models for load carrying structures are significant elements in the evaluation of the performance and sustainability of existing and new structures. Furthermore, reliable service life models are prerequisites for the evaluation of the sustainability of maintenance strategies...... should define a framework in which materials research results eventually should fit in and on the other side the materials research should define needs and capabilities in structural modelling. Integrated materials-structural models of a general nature are almost non-existent in the field of cement based...

  2. Seclazone Reactor Modeling And Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Osinga, T. [ETH-Zuerich (Switzerland); Olalde, G. [CNRS Odeillo (France); Steinfeld, A. [PSI and ETHZ (Switzerland)

    2005-03-01

    A numerical model is formulated for the SOLZINC solar chemical reactor for the production of Zn by carbothermal reduction of ZnO. The model involves solving, by the finite-volume technique, a 1D unsteady state energy equation that couples heat transfer to the chemical kinetics for a shrinking packed bed exposed to thermal radiation. Validation is accomplished by comparison with experimentally measured temperature profiles and Zn production rates as a function of time, obtained for a 5-kW solar reactor tested at PSI's solar furnace. (author)

  3. Experimental In Vivo Models of Candidiasis

    Directory of Open Access Journals (Sweden)

    Esther Segal

    2018-02-01

    Full Text Available Candidiasis is a multifaceted fungal disease including mucosal-cutaneous, visceral, and disseminated infections caused by yeast species of the genus Candida. Candida infections are among the most common human mycoses. Candida species are the third to fourth most common isolates from bloodstream infections in neutropenic or immunocompromised hospitalized patients. The mucosal-cutaneous forms—particularly vaginal infections—have a high prevalence. Vaginitis caused by Candida species is the second most common vaginal infection. Hence, candidiasis is a major subject for research, including experimental in vivo models to study pathogenesis, prevention, or therapy of the disease. The following review article will focus on various experimental in vivo models in different laboratory animals, such as mammals (mice, rats, rabbits, the fruit fly–Drosophila melanogaster, the larvae of the moth Galleria mellonella, or the free-living nematode Caenorhabditis elegans. The review will describe the induction of the different clinical forms of candidiasis in the various models and the validity of such models in mimicking the human clinical situations. The use of such models for the assessment of antifungal drugs, evaluation of potential vaccines to protect before candidiasis, exploration of Candida virulence factors, and comparison of pathogenicity of different Candida species will be included in the review. All of the above will be reported as based on published studies of numerous investigators as well as on the research of the author and his group.

  4. Modeling vibration response and damping of cables and cabled structures

    Science.gov (United States)

    Spak, Kaitlin S.; Agnes, Gregory S.; Inman, Daniel J.

    2015-02-01

    In an effort to model the vibration response of cabled structures, the distributed transfer function method is developed to model cables and a simple cabled structure. The model includes shear effects, tension, and hysteretic damping for modeling of helical stranded cables, and includes a method for modeling cable attachment points using both linear and rotational damping and stiffness. The damped cable model shows agreement with experimental data for four types of stranded cables, and the damped cabled beam model shows agreement with experimental data for the cables attached to a beam structure, as well as improvement over the distributed mass method for cabled structure modeling.

  5. Endometriose: modelo experimental em ratas Endometriosis: experimental model in rats

    Directory of Open Access Journals (Sweden)

    Eduardo Schor

    1999-06-01

    Full Text Available Objetivo: divulgar a metodologia da indução de endometriose experimental em animais de laboratório. Método: utilizamos ratas albinas, virgens, adultas de aproximadamente três meses de idade, que foram inicialmente anestesiadas pelo éter etílico. Aberta a cavidade abdominal, identificamos os cornos uterinos e retiramos um fragmento de aproximadamente 4 cm do corno uterino direito. Esse fragmento foi mergulhado em solução fisiológica e sob lupa estereoscópica foi separado o endométrio do miométrio e feitos retângulos de aproximadamente 4 por 5 mm. Esses foram fixados por meio de fio de sutura, sobre vasos sangüíneos visíveis a olho nu, na parede lateral do abdômen, tomando-se sempre o cuidado de manter a porção do endométrio livre voltada para a luz da cavidade abdominal. Após 21 dias os animais foram novamente operados para verificarmos o tamanho dos implantes e para retirada do endométrio ectópico para análise histológica. Resultados: macroscopicamente observamos crescimento significativo dos implantes endometriais. Ao exame microscópico pudemos observar a presença de epitélio glandular e estroma semelhantes ao do endométrio tópico. Conclusões: o modelo utilizado reproduz a doença, em ratas, sendo método auxiliar de valia para estudar esta afecção, principalmente a ação de medicamentos sobre esses implantes.Purpose: to demonstrate the experimental endometriosis induction in animals. Method: we used adult female Wistar rats weighing 200 - 250 g anesthetized with ethyl ether to open the abdominal cavity. After identifying the uterine horns, we removed an approximately 4 cm fragment from the right uterine horn. This fragment was placed in physiological saline and, with the aid of a stereoscopic magnifying glass, the endometrium was separated from the myometrium and cut into rectangles of approximately 4 x 5 mm. These rectangles were fastened to the lateral abdominal wall near great blood vessels, taking care

  6. A New Non-Equilibrium Thermodynamic Fractional Visco-Inelastic Model to Predict Experimentally Inaccessible Processes and Investigate Pathophysiological Cellular Structures

    Directory of Open Access Journals (Sweden)

    Francesco Farsaci

    2017-11-01

    Full Text Available After remarking on non-equilibrium thermodynamics with internal variables, this paper highlights the importance of these variables to the study of biological systems. Internal variables can provide a more detailed description of biological processes that occur inside cells, tissues and organs. In order to introduce a fractional model on a visco-inelastic medium based on Kluitenberg’s non-equilibrium thermodynamics, the origin of the complex dynamic modulus is shown by means of linear response theory. This research recalls our previous work to develop an ultrasound wave technique that allows us to investigate biological systems, and introduces the fractional visco-inelastic model and relative generalized relaxation time, to show that it is possible to obtain the Cole–Cole model in a particular case.

  7. Models for Experimental High Density Housing

    Science.gov (United States)

    Bradecki, Tomasz; Swoboda, Julia; Nowak, Katarzyna; Dziechciarz, Klaudia

    2017-10-01

    The article presents the effects of research on models of high density housing. The authors present urban projects for experimental high density housing estates. The design was based on research performed on 38 examples of similar housing in Poland that have been built after 2003. Some of the case studies show extreme density and that inspired the researchers to test individual virtual solutions that would answer the question: How far can we push the limits? The experimental housing projects show strengths and weaknesses of design driven only by such indexes as FAR (floor attenuation ratio - housing density) and DPH (dwellings per hectare). Although such projects are implemented, the authors believe that there are reasons for limits since high index values may be in contradiction to the optimum character of housing environment. Virtual models on virtual plots presented by the authors were oriented toward maximising the DPH index and DAI (dwellings area index) which is very often the main driver for developers. The authors also raise the question of sustainability of such solutions. The research was carried out in the URBAN model research group (Gliwice, Poland) that consists of academic researchers and architecture students. The models reflect architectural and urban regulations that are valid in Poland. Conclusions might be helpful for urban planners, urban designers, developers, architects and architecture students.

  8. Experimental animal modelling for TB vaccine development

    Directory of Open Access Journals (Sweden)

    Pere-Joan Cardona

    2017-03-01

    Full Text Available Research for a novel vaccine to prevent tuberculosis is an urgent medical need. The current vaccine, BCG, has demonstrated a non-homogenous efficacy in humans, but still is the gold standard to be improved upon. In general, the main indicator for testing the potency of new candidates in animal models is the reduction of the bacillary load in the lungs at the acute phase of the infection. Usually, this reduction is similar to that induced by BCG, although in some cases a weak but significant improvement can be detected, but none of candidates are able to prevent establishment of infection. The main characteristics of several laboratory animals are reviewed, reflecting that none are able to simulate the whole characteristics of human tuberculosis. As, so far, no surrogate of protection has been found, it is important to test new candidates in several models in order to generate convincing evidence of efficacy that might be better than that of BCG in humans. It is also important to investigate the use of “in silico” and “ex vivo” models to better understand experimental data and also to try to replace, or at least reduce and refine experimental models in animals.

  9. Surface physics theoretical models and experimental methods

    CERN Document Server

    Mamonova, Marina V; Prudnikova, I A

    2016-01-01

    The demands of production, such as thin films in microelectronics, rely on consideration of factors influencing the interaction of dissimilar materials that make contact with their surfaces. Bond formation between surface layers of dissimilar condensed solids-termed adhesion-depends on the nature of the contacting bodies. Thus, it is necessary to determine the characteristics of adhesion interaction of different materials from both applied and fundamental perspectives of surface phenomena. Given the difficulty in obtaining reliable experimental values of the adhesion strength of coatings, the theoretical approach to determining adhesion characteristics becomes more important. Surface Physics: Theoretical Models and Experimental Methods presents straightforward and efficient approaches and methods developed by the authors that enable the calculation of surface and adhesion characteristics for a wide range of materials: metals, alloys, semiconductors, and complex compounds. The authors compare results from the ...

  10. Structural model of the hUbA1-UbcH10 quaternary complex: in silico and experimental analysis of the protein-protein interactions between E1, E2 and ubiquitin.

    Directory of Open Access Journals (Sweden)

    Stefania Correale

    Full Text Available UbcH10 is a component of the Ubiquitin Conjugation Enzymes (Ubc; E2 involved in the ubiquitination cascade controlling the cell cycle progression, whereby ubiquitin, activated by E1, is transferred through E2 to the target protein with the involvement of E3 enzymes. In this work we propose the first three dimensional model of the tetrameric complex formed by the human UbA1 (E1, two ubiquitin molecules and UbcH10 (E2, leading to the transthiolation reaction. The 3D model was built up by using an experimentally guided incremental docking strategy that combined homology modeling, protein-protein docking and refinement by means of molecular dynamics simulations. The structural features of the in silico model allowed us to identify the regions that mediate the recognition between the interacting proteins, revealing the active role of the ubiquitin crosslinked to E1 in the complex formation. Finally, the role of these regions involved in the E1-E2 binding was validated by designing short peptides that specifically interfere with the binding of UbcH10, thus supporting the reliability of the proposed model and representing valuable scaffolds for the design of peptidomimetic compounds that can bind selectively to Ubcs and inhibit the ubiquitylation process in pathological disorders.

  11. Experimental model of arteriovenous fistula in pigs

    International Nuclear Information System (INIS)

    Suh, Dae Chul; Seo, Dong Man; Kim, Hyun Jin and others

    1997-01-01

    To establish an experimental model of arteriovenous fistula in pigs. Ten fistulas were created in eight pigs, and angiography was performed 3 to 5 days after surgery. A follow-up angiogram of three fistulas was obtained 2 to 12 weeks later. In one animal, pathologic examination showed occlusion 8 weeks after a successful operations. Eight angiograms of nine fistulas in seven pigs were obtained; one animal died due to cardiac failure. In six pigs, high-flow fistulas were shown to be present, and in two, the fistulas were slow flow; a pseudoaneurysm was seen in one. A follow-up angiogram obtained in three cases showed occlusion of the fistula. Pathologic examination of one animal showed fibrosis in the occluded portion of the fistula. An arteriovenous fistula model was surgically established in 80% of cases; during follow-up, three fistulas were seen to be occluded due to fibrosis. This model can therefore be used within one week of surgery

  12. PRODUCT STRUCTURE DIGITAL MODEL

    Directory of Open Access Journals (Sweden)

    V.M. Sineglazov

    2005-02-01

    Full Text Available  Research results of representation of product structure made by means of CADDS5 computer-aided design (CAD system, Product Data Management Optegra (PDM system and Product Life Cycle Management Wind-chill system (PLM, are examined in this work. Analysis of structure component development and its storage in various systems is carried out. Algorithms of structure transformation required for correct representation of the structure are considered. Management analysis of electronic mockup presentation of the product structure is carried out for Windchill system.

  13. Structural dynamic modifications via models

    Indian Academy of Sciences (India)

    of structural dynamic optimization techniques. A review of structural optimization in vibratory environments is given by Rao (1989). 2. SDM techniques. SDM methods may be broadly divided into two groups. Those which employ a model of the structure and those that use dynamic test data directly. The model used by the ...

  14. 3D-DART: a DNA structure modelling server

    NARCIS (Netherlands)

    van Dijk, M.; Bonvin, A.M.J.J.

    2009-01-01

    There is a growing interest in structural studies of DNA by both experimental and computational approaches. Often, 3D-structural models of DNA are required, for instance, to serve as templates for homology modeling, as starting structures for macro-molecular docking or as scaffold for NMR structure

  15. Numerical and experimental study of bistable plates for morphing structures

    Science.gov (United States)

    Nicassio, F.; Scarselli, G.; Avanzini, G.; Del Core, G.

    2017-04-01

    This study is concerned with the activation energy threshold of bistable composite plates in order to tailor a bistable system for specific aeronautical applications. The aim is to explore potential configurations of the bistable plates and their dynamic behavior for designing novel morphing structure suitable for aerodynamic surfaces and, as a possible further application, for power harvesters. Bistable laminates have two stable mechanical shapes that can withstand aerodynamic loads without additional constraint forces or locking mechanisms. This kind of structures, when properly loaded, snap-through from one stable configuration to another, causing large strains that can also be used for power harvesting scopes. The transition between the stable states of the composite laminate can be triggered, in principle, simply by aerodynamic loads (pilot, disturbance or passive inputs) without the need of servo-activated control systems. Both numerical simulations based on Finite Element models and experimental testing based on different activating forcing spectra are used to validate this concept. The results show that dynamic activation of bistable plates depend on different parameters that need to be carefully managed for their use as aircraft passive wing flaps.

  16. Superficial tension: experimental model with simple materials

    Directory of Open Access Journals (Sweden)

    Tintori Ferreira, María Alejandra

    2012-09-01

    Full Text Available In this work appears a didactic offer based on an experimental activity using materials of very low cost, orientated to achieving that the student understand and interpret the phenomenon of superficial tension together with the importance of the modeling in sciences. It has as principal aim of education bring the student over to the mechanics of the static fluids and the intermolecular forces, combining scientific contents with questions near to the student what provides an additional motivation to the reflection of the scientific investigation.

  17. Relation between native ensembles and experimental structures of proteins

    DEFF Research Database (Denmark)

    Best, R. B.; Lindorff-Larsen, Kresten; DePristo, M. A.

    2006-01-01

    Different experimental structures of the same protein or of proteins with high sequence similarity contain many small variations. Here we construct ensembles of "high-sequence similarity Protein Data Bank" (HSP) structures and consider the extent to which such ensembles represent the structural...... Data Bank ensembles; moreover, we show that the effects of uncertainties in structure determination are insufficient to explain the results. These results highlight the importance of accounting for native-state protein dynamics in making comparisons with ensemble-averaged experimental data and suggest...... heterogeneity of the native state in solution. We find that different NMR measurements probing structure and dynamics of given proteins in solution, including order parameters, scalar couplings, and residual dipolar couplings, are remarkably well reproduced by their respective high-sequence similarity Protein...

  18. Automated functional classification of experimental and predicted protein structures

    Directory of Open Access Journals (Sweden)

    Samudrala Ram

    2006-06-01

    Full Text Available Abstract Background Proteins that are similar in sequence or structure may perform different functions in nature. In such cases, function cannot be inferred from sequence or structural similarity. Results We analyzed experimental structures belonging to the Structural Classification of Proteins (SCOP database and showed that about half of them belong to multi-functional fold families for which protein similarity alone is not adequate to assign function. We also analyzed predicted structures from the LiveBench and the PDB-CAFASP experiments and showed that accurate homology-based functional assignments cannot be achieved approximately one third of the time, when the protein is a member of a multi-functional fold family. We then conducted extended performance evaluation and comparisons on both experimental and predicted structures using our Functional Signatures from Structural Alignments (FSSA algorithm that we previously developed to handle the problem of classifying proteins belonging to multi-functional fold families. Conclusion The results indicate that the FSSA algorithm has better accuracy when compared to homology-based approaches for functional classification of both experimental and predicted protein structures, in part due to its use of local, as opposed to global, information for classifying function. The FSSA algorithm has also been implemented as a webserver and is available at http://protinfo.compbio.washington.edu/fssa.

  19. Probabilistic modeling of timber structures

    DEFF Research Database (Denmark)

    Köhler, Jochen; Sørensen, John Dalsgaard; Faber, Michael Havbro

    2007-01-01

    The present paper contains a proposal for the probabilistic modeling of timber material properties. It is produced in the context of the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS) [Joint Committee of Structural Safety. Probabilistic Model Code, Internet Publ...

  20. Graphical Models for Quasi-Experimental Designs

    Science.gov (United States)

    Kim, Yongnam; Steiner, Peter M.; Hall, Courtney E.; Su, Dan

    2016-01-01

    Experimental and quasi-experimental designs play a central role in estimating cause-effect relationships in education, psychology, and many other fields of the social and behavioral sciences. This paper presents and discusses the causal graphs of experimental and quasi-experimental designs. For quasi-experimental designs the authors demonstrate…

  1. Structured building model reduction toward parallel simulation

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Justin R. [Cornell University; Hencey, Brondon M. [Cornell University

    2013-08-26

    Building energy model reduction exchanges accuracy for improved simulation speed by reducing the number of dynamical equations. Parallel computing aims to improve simulation times without loss of accuracy but is poorly utilized by contemporary simulators and is inherently limited by inter-processor communication. This paper bridges these disparate techniques to implement efficient parallel building thermal simulation. We begin with a survey of three structured reduction approaches that compares their performance to a leading unstructured method. We then use structured model reduction to find thermal clusters in the building energy model and allocate processing resources. Experimental results demonstrate faster simulation and low error without any interprocessor communication.

  2. Dynamic term structure models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Meldrum, Andrew

    pricing factors using the sequential regression approach. Our findings suggest that the two models largely provide the same in-sample fit, but loadings from ordinary and risk-adjusted Campbell-Shiller regressions are generally best matched by the shadow rate models. We also find that the shadow rate...... models perform better than the QTSMs when forecasting bond yields out of sample....

  3. Structural sensitivity of biological models revisited.

    Science.gov (United States)

    Cordoleani, Flora; Flora, Cordoleani; Nerini, David; David, Nerini; Gauduchon, Mathias; Mathias, Gauduchon; Morozov, Andrew; Andrew, Morozov; Poggiale, Jean-Christophe; Jean-Christophe, Poggiale

    2011-08-21

    Enhancing the predictive power of models in biology is a challenging issue. Among the major difficulties impeding model development and implementation are the sensitivity of outcomes to variations in model parameters, the problem of choosing of particular expressions for the parametrization of functional relations, and difficulties in validating models using laboratory data and/or field observations. In this paper, we revisit the phenomenon which is referred to as structural sensitivity of a model. Structural sensitivity arises as a result of the interplay between sensitivity of model outcomes to variations in parameters and sensitivity to the choice of model functions, and this can be somewhat of a bottleneck in improving the models predictive power. We provide a rigorous definition of structural sensitivity and we show how we can quantify the degree of sensitivity of a model based on the Hausdorff distance concept. We propose a simple semi-analytical test of structural sensitivity in an ODE modeling framework. Furthermore, we emphasize the importance of directly linking the variability of field/experimental data and model predictions, and we demonstrate a way of assessing the robustness of modeling predictions with respect to data sampling variability. As an insightful illustrative example, we test our sensitivity analysis methods on a chemostat predator-prey model, where we use laboratory data on the feeding of protozoa to parameterize the predator functional response. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Equine CTNNB1 and PECAM1 nucleotide structure and expression analyses in an experimental model of normal and pathological wound repair

    Directory of Open Access Journals (Sweden)

    Theoret Christine L

    2008-01-01

    Full Text Available Abstract Background Wound healing in horses is fraught with complications. Specifically, wounds on horse limbs often develop exuberant granulation tissue which behaves clinically like a benign tumor and resembles the human keloid in that the evolving scar is trapped in the proliferative phase of repair, leading to fibrosis. Clues gained from the study of over-scarring in horses should eventually lead to new insights into how to prevent unwanted scar formation in humans. cDNA fragments corresponding to CTNNB1 (coding for β-catenin and PECAM1, genes potentially contributing to the proliferative phase of repair, were previously identified in a mRNA expression study as being up-regulated in 7 day wound biopsies from horses. The aim of the present study was to clone full-length equine CTNNB1 and PECAM1 cDNAs and to study the spatio-temporal expression of mRNAs and corresponding proteins during repair of body and limb wounds in a horse model. Results The temporal pattern of the two genes was similar; except for CTNNB1 in limb wounds, wounding caused up-regulation of mRNA which did not return to baseline by the end of the study. Relative over-expression of both CTNNB1 and PECAM1 mRNA was noted in body wounds compared to limb wounds. Immunostaining for both β-catenin and PECAM1 was principally observed in endothelial cells and fibroblasts and was especially pronounced in wounds having developed exuberant granulation tissue. Conclusion This study is the first to characterize equine cDNA for CTNNB1 and PECAM1 and to document that these genes are expressed during wound repair in horses. It appears that β-catenin may be regulated in a post-transcriptional manner while PECAM1 might help thoracic wounds mount an efficient inflammatory response in contrast to what is observed in limb wounds. Furthermore, data from this study suggest that β-catenin and PECAM1 might interact to modulate endothelial cell and fibroblast proliferation during wound repair in the

  5. Equine CTNNB1 and PECAM1 nucleotide structure and expression analyses in an experimental model of normal and pathological wound repair

    Science.gov (United States)

    Miragliotta, Vincenzo; Ipiña, Zoë; Lefebvre-Lavoie, Josiane; Lussier, Jacques G; Theoret, Christine L

    2008-01-01

    Background Wound healing in horses is fraught with complications. Specifically, wounds on horse limbs often develop exuberant granulation tissue which behaves clinically like a benign tumor and resembles the human keloid in that the evolving scar is trapped in the proliferative phase of repair, leading to fibrosis. Clues gained from the study of over-scarring in horses should eventually lead to new insights into how to prevent unwanted scar formation in humans. cDNA fragments corresponding to CTNNB1 (coding for β-catenin) and PECAM1, genes potentially contributing to the proliferative phase of repair, were previously identified in a mRNA expression study as being up-regulated in 7 day wound biopsies from horses. The aim of the present study was to clone full-length equine CTNNB1 and PECAM1 cDNAs and to study the spatio-temporal expression of mRNAs and corresponding proteins during repair of body and limb wounds in a horse model. Results The temporal pattern of the two genes was similar; except for CTNNB1 in limb wounds, wounding caused up-regulation of mRNA which did not return to baseline by the end of the study. Relative over-expression of both CTNNB1 and PECAM1 mRNA was noted in body wounds compared to limb wounds. Immunostaining for both β-catenin and PECAM1 was principally observed in endothelial cells and fibroblasts and was especially pronounced in wounds having developed exuberant granulation tissue. Conclusion This study is the first to characterize equine cDNA for CTNNB1 and PECAM1 and to document that these genes are expressed during wound repair in horses. It appears that β-catenin may be regulated in a post-transcriptional manner while PECAM1 might help thoracic wounds mount an efficient inflammatory response in contrast to what is observed in limb wounds. Furthermore, data from this study suggest that β-catenin and PECAM1 might interact to modulate endothelial cell and fibroblast proliferation during wound repair in the horse. PMID:18237399

  6. Experimental Oral Candidiasis in Animal Models

    Science.gov (United States)

    Samaranayake, Yuthika H.; Samaranayake, Lakshman P.

    2001-01-01

    Oral candidiasis is as much the final outcome of the vulnerability of the host as of the virulence of the invading organism. We review here the extensive literature on animal experiments mainly appertaining to the host predisposing factors that initiate and perpetuate these infections. The monkey, rat, and mouse are the choice models for investigating oral candidiasis, but comparisons between the same or different models appear difficult, because of variables such as the study design, the number of animals used, their diet, the differences in Candida strains, and the duration of the studies. These variables notwithstanding, the following could be concluded. (i) The primate model is ideal for investigating Candida-associated denture stomatitis since both erythematous and pseudomembranous lesions have been produced in monkeys with prosthetic plates; they are, however, expensive and difficult to obtain and maintain. (ii) The rat model (both Sprague-Dawley and Wistar) is well proven for observing chronic oral candidal colonization and infection, due to the ease of breeding and handling and their ready availability. (iii) Mice are similar, but in addition there are well characterized variants simulating immunologic and genetic abnormalities (e.g., athymic, euthymic, murine-acquired immune deficiency syndrome, and severe combined immunodeficient models) and hence are used for short-term studies relating the host immune response and oral candidiasis. Nonetheless, an ideal, relatively inexpensive model representative of the human oral environment in ecological and microbiological terms is yet to be described. Until such a model is developed, researchers should pay attention to standardization of the experimental protocols described here to obtain broadly comparable and meaningful data. PMID:11292645

  7. Modeling Structural Brain Connectivity

    DEFF Research Database (Denmark)

    Ambrosen, Karen Marie Sandø

    The human brain consists of a gigantic complex network of interconnected neurons. Together all these connections determine who we are, how we react and how we interpret the world. Knowledge about how the brain is connected can further our understanding of the brain’s structural organization, help...... improve diagnosis, and potentially allow better treatment of a wide range of neurological disorders. Tractography based on diffusion magnetic resonance imaging is a unique tool to estimate this “structural connectivity” of the brain non-invasively and in vivo. During the last decade, brain connectivity...... has increasingly been analyzed using graph theoretic measures adopted from network science and this characterization of the brain’s structural connectivity has been shown to be useful for the classification of populations, such as healthy and diseased subjects. The structural connectivity of the brain...

  8. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  9. Experimental study on beam for composite CES structural system

    Science.gov (United States)

    Matsui, Tomoya

    2017-10-01

    Development study on Concrete Encase Steel (CES) composite structure system has been continuously conducted toward the practical use. CES structure is composed of steel and fiber reinforced concrete. In previous study, it was found that CES structure has good seismic performance from experimental study of columns, beam - column joints, shear walls and a two story two span frame. However, as fundamental study on CES beam could be lacking, it is necessary to understand the structural performance of CES beam. In this study, static loading tests of CES beams were conducted with experimental valuable of steel size, the presence or absence of slab and thickness of slab. And restoring characteristics, failure behavior, deformation behavior, and strength evaluation method of CES beam were investigated. As the results, it was found that CES beam showed stable hysteresis behavior. Furthermore it was found that the flexural strength of the CES beam could be evaluated by superposition strength theory.

  10. Reconstruction of dynamic structures of experimental setups based on measurable experimental data only

    Science.gov (United States)

    Chen, Tian-Yu; Chen, Yang; Yang, Hu-Jiang; Xiao, Jing-Hua; Hu, Gang

    2018-03-01

    Nowadays, massive amounts of data have been accumulated in various and wide fields, it has become today one of the central issues in interdisciplinary fields to analyze existing data and extract as much useful information as possible from data. It is often that the output data of systems are measurable while dynamic structures producing these data are hidden, and thus studies to reveal system structures by analyzing available data, i.e., reconstructions of systems become one of the most important tasks of information extractions. In the past, most of the works in this respect were based on theoretical analyses and numerical verifications. Direct analyses of experimental data are very rare. In physical science, most of the analyses of experimental setups were based on the first principles of physics laws, i.e., so-called top-down analyses. In this paper, we conducted an experiment of “Boer resonant instrument for forced vibration” (BRIFV) and inferred the dynamic structure of the experimental set purely from the analysis of the measurable experimental data, i.e., by applying the bottom-up strategy. Dynamics of the experimental set is strongly nonlinear and chaotic, and itʼs subjects to inevitable noises. We proposed to use high-order correlation computations to treat nonlinear dynamics; use two-time correlations to treat noise effects. By applying these approaches, we have successfully reconstructed the structure of the experimental setup, and the dynamic system reconstructed with the measured data reproduces good experimental results in a wide range of parameters.

  11. Experimental validation of solid rocket motor damping models

    Science.gov (United States)

    Riso, Cristina; Fransen, Sebastiaan; Mastroddi, Franco; Coppotelli, Giuliano; Trequattrini, Francesco; De Vivo, Alessio

    2017-12-01

    In design and certification of spacecraft, payload/launcher coupled load analyses are performed to simulate the satellite dynamic environment. To obtain accurate predictions, the system damping properties must be properly taken into account in the finite element model used for coupled load analysis. This is typically done using a structural damping characterization in the frequency domain, which is not applicable in the time domain. Therefore, the structural damping matrix of the system must be converted into an equivalent viscous damping matrix when a transient coupled load analysis is performed. This paper focuses on the validation of equivalent viscous damping methods for dynamically condensed finite element models via correlation with experimental data for a realistic structure representative of a slender launch vehicle with solid rocket motors. A second scope of the paper is to investigate how to conveniently choose a single combination of Young's modulus and structural damping coefficient—complex Young's modulus—to approximate the viscoelastic behavior of a solid propellant material in the frequency band of interest for coupled load analysis. A scaled-down test article inspired to the Z9-ignition Vega launcher configuration is designed, manufactured, and experimentally tested to obtain data for validation of the equivalent viscous damping methods. The Z9-like component of the test article is filled with a viscoelastic material representative of the Z9 solid propellant that is also preliminarily tested to investigate the dependency of the complex Young's modulus on the excitation frequency and provide data for the test article finite element model. Experimental results from seismic and shock tests performed on the test configuration are correlated with numerical results from frequency and time domain analyses carried out on its dynamically condensed finite element model to assess the applicability of different equivalent viscous damping methods to describe

  12. Probabilistic Modeling of Timber Structures

    DEFF Research Database (Denmark)

    Köhler, J.D.; Sørensen, John Dalsgaard; Faber, Michael Havbro

    2005-01-01

    The present paper contains a proposal for the probabilistic modeling of timber material properties. It is produced in the context of the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS) and of the COST action E24 'Reliability of Timber Structures'. The present pro...... probabilistic model for these basic properties is presented and possible refinements are given related to updating of the probabilistic model given new information, modeling of the spatial variation of strength properties and the duration of load effects.......The present paper contains a proposal for the probabilistic modeling of timber material properties. It is produced in the context of the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS) and of the COST action E24 'Reliability of Timber Structures'. The present...

  13. Phenomenological models of raft structure

    Science.gov (United States)

    Shirotori, H.; Komura, S.; Kato, T.; Olmsted, P. D.

    2004-04-01

    We propose two phenomenological models describing the phase behavior of lipid-lipid systems and lipid-cholesterol systems in order to understand the "rafts" in cell membranes. In our models, the coupling between the lateral phase separation and the internal degree of freedom of a lipid membrane is considered. The calculated phase diagrams are in semiquantitative agreement with the experimental phase diagrams.

  14. [Skin defect modeling in experimental animals].

    Science.gov (United States)

    Oleshko, A N; Kornienko, V V; Tkachenko, Yu A; Kurganskaya, V A

    2015-02-01

    To assess the skin regeneration and explore new medical devices for the treatment of skin defects is necessary to conduct long-term experiments using laboratory animals. Currently, there are many methods for skin trauma modeling but most of them have disadvantages that limit their use. The purpose of this work - the development of an experimental model of the formation of skin defect of various etiologies with the specified parameters of depth and area of damage to the absence of systemic effects on the animal's body. We have developed an installation that allows us to form a skin defect of mechanical, thermal and chemical etiology with area from 1.76 cm2 to 2.0 cm2. The experiment was conducted on 18 male laboratory rats to examine the effectiveness of current method and control the depth and area of the defect. As a result of the new methodology, we were able to carry out simulation skin injuries of different etiology on laboratory animals in the short term and reduce the severity of injuries to extend the life span of animals to monitor the repair processes, as well as to standardize the modeling of injuries according to the criteria of area and depth of the defect.

  15. Modeling a nuclear reactor for experimental purposes

    International Nuclear Information System (INIS)

    Berta, V.T.

    1980-01-01

    The Loss-of-Fluid Test (LOFT) Facility is a scale model of a commercial PWR and is as fully functional and operational as the generic commercial counterpart. LOFT was designed and built for experimental purposes as part of the overall NRC reactor safety research program. The purpose of LOFT is to assess the capability of reactor safety systems to perform their intended functions during occurrences of off-normal conditions in a commercial nuclear reactor. Off-normal conditions arising from large and small break loss-of-coolant accidents (LOCA), operational transients, and anticipated transients without scram (ATWS) were to be investigated. This paper describes the LOFT model of the generic PWR and summarizes the experiments that have been conducted in the context of the significant findings involving the complex transient thermal-hydraulics and the consequent effects on the commercial reactor analytical licensing techniques. Through these techniques the validity of the LOFT model as a scaled counterpart of the generic PWR is shown

  16. Experimental models of autoimmune inflammatory ocular diseases

    Directory of Open Access Journals (Sweden)

    Fabio Gasparin

    2012-04-01

    Full Text Available Ocular inflammation is one of the leading causes of blindness and loss of vision. Human uveitis is a complex and heterogeneous group of diseases characterized by inflammation of intraocular tissues. The eye may be the only organ involved, or uveitis may be part of a systemic disease. A significant number of cases are of unknown etiology and are labeled idiopathic. Animal models have been developed to the study of the physiopathogenesis of autoimmune uveitis due to the difficulty in obtaining human eye inflamed tissues for experiments. Most of those models are induced by injection of specific photoreceptors proteins (e.g., S-antigen, interphotoreceptor retinoid-binding protein, rhodopsin, recoverin, phosducin. Non-retinal antigens, including melanin-associated proteins and myelin basic protein, are also good inducers of uveitis in animals. Understanding the basic mechanisms and pathogenesis of autoimmune ocular diseases are essential for the development of new treatment approaches and therapeutic agents. The present review describes the main experimental models of autoimmune ocular inflammatory diseases.

  17. SPAR Model Structural Efficiencies

    Energy Technology Data Exchange (ETDEWEB)

    John Schroeder; Dan Henry

    2013-04-01

    The Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are supporting initiatives aimed at improving the quality of probabilistic risk assessments (PRAs). Included in these initiatives are the resolution of key technical issues that are have been judged to have the most significant influence on the baseline core damage frequency of the NRC’s Standardized Plant Analysis Risk (SPAR) models and licensee PRA models. Previous work addressed issues associated with support system initiating event analysis and loss of off-site power/station blackout analysis. The key technical issues were: • Development of a standard methodology and implementation of support system initiating events • Treatment of loss of offsite power • Development of standard approach for emergency core cooling following containment failure Some of the related issues were not fully resolved. This project continues the effort to resolve outstanding issues. The work scope was intended to include substantial collaboration with EPRI; however, EPRI has had other higher priority initiatives to support. Therefore this project has addressed SPAR modeling issues. The issues addressed are • SPAR model transparency • Common cause failure modeling deficiencies and approaches • Ac and dc modeling deficiencies and approaches • Instrumentation and control system modeling deficiencies and approaches

  18. Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

    Science.gov (United States)

    Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

    1994-03-01

    A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

  19. A MATLAB toolbox for structural kinetic modeling.

    Science.gov (United States)

    Girbig, Dorothee; Selbig, Joachim; Grimbs, Sergio

    2012-10-01

    Structural kinetic modeling (SKM) enables the analysis of dynamical properties of metabolic networks solely based on topological information and experimental data. Current SKM-based experiments are hampered by the time-intensive process of assigning model parameters and choosing appropriate sampling intervals for Monte-Carlo experiments. We introduce a toolbox for the automatic and efficient construction and evaluation of structural kinetic models (SK models). Quantitative and qualitative analyses of network stability properties are performed in an automated manner. We illustrate the model building and analysis process in detailed example scripts that provide toolbox implementations of previously published literature models. The source code is freely available for download at http://bioinformatics.uni-potsdam.de/projects/skm. girbig@mpimp-golm.mpg.de.

  20. Effects of Anethole in Nociception Experimental Models

    Directory of Open Access Journals (Sweden)

    Alessandra Mileni Versuti Ritter

    2014-01-01

    Full Text Available This study investigated the antinociceptive activity of anethole (anethole 1-methoxy-4-benzene (1-propenyl, major compound of the essential oil of star anise (Illicium verum, in different experimental models of nociception. The animals were pretreated with anethole (62.5, 125, 250, and 500 mg/kg one hour before the experiments. To eliminate a possible sedative effect of anethole, the open field test was conducted. Anethole (62.5, 125, 250, and 500 mg/kg showed an antinociceptive effect in the writhing model induced by acetic acid, in the second phase of the formalin test (125 and 250 mg/kg in the test of glutamate (62.5, 125, and 250 mg/kg, and expresses pain induced by ACF (250 mg/kg. In contrast, anethole was not able to increase the latency time on the hot plate and decrease the number of flinches during the initial phase of the formalin test in any of the doses tested. It was also demonstrated that anethole has no association with sedative effects. Therefore, these data showed that anethole, at all used doses, has no sedative effect and has an antinociceptive effect. This effect may be due to a decrease in the production/release of inflammatory mediators.

  1. Effects of anethole in nociception experimental models.

    Science.gov (United States)

    Ritter, Alessandra Mileni Versuti; Ames, Franciele Queiroz; Otani, Fernando; de Oliveira, Rubia Maria Weffort; Cuman, Roberto Kenji Nakamura; Bersani-Amado, Ciomar Aparecida

    2014-01-01

    This study investigated the antinociceptive activity of anethole (anethole 1-methoxy-4-benzene (1-propenyl)), major compound of the essential oil of star anise (Illicium verum), in different experimental models of nociception. The animals were pretreated with anethole (62.5, 125, 250, and 500 mg/kg) one hour before the experiments. To eliminate a possible sedative effect of anethole, the open field test was conducted. Anethole (62.5, 125, 250, and 500 mg/kg) showed an antinociceptive effect in the writhing model induced by acetic acid, in the second phase of the formalin test (125 and 250 mg/kg) in the test of glutamate (62.5, 125, and 250 mg/kg), and expresses pain induced by ACF (250 mg/kg). In contrast, anethole was not able to increase the latency time on the hot plate and decrease the number of flinches during the initial phase of the formalin test in any of the doses tested. It was also demonstrated that anethole has no association with sedative effects. Therefore, these data showed that anethole, at all used doses, has no sedative effect and has an antinociceptive effect. This effect may be due to a decrease in the production/release of inflammatory mediators.

  2. Tendon healing in vivo. An experimental model.

    Science.gov (United States)

    Abrahamsson, S O; Lundborg, G; Lohmander, L S

    1989-01-01

    Flexor tendon segments were incubated in a diffusion chamber in the subcutis of rabbits. Tendons incubated up to 6 weeks in the diffusion chamber showed proliferating and migrating cells from the epitenon cell layer as well as viable endotenon cells. Explants frozen in liquid nitrogen prior to incubation showed no signs of extrinsic cell contamination and remained non-viable indicating that no cell penetration occurred through the Millipore filter and that cell division seen in non-frozen and incubated tendons was an expression of intrinsic cellular proliferative capacity of the tendon. In tendon segments incubated in chambers for three weeks, collagen synthesis was reduced by 50% and the rate of cell proliferation measured as 3H-thymidine incorporation, was 15 times that of native tendons. Frozen and incubated tendons showed only traces of remaining matrix synthesis or cell proliferation. With this experimental model we have histologically and biochemically shown that tendons may survive and heal while the nutrition exclusively could be based on diffusion and the tendons have an intrinsic capacity of healing. The described model enables further studies on tendon healing and its regulation.

  3. Experimental models for Murray’s law

    Science.gov (United States)

    Akita, Dai; Kunita, Itsuki; Fricker, Mark D.; Kuroda, Shigeru; Sato, Katsuhiko; Nakagaki, Toshiyuki

    2017-01-01

    Transport networks are ubiquitous in multicellular organisms and include leaf veins, fungal mycelia and blood vessels. While transport of materials and signals through the network plays a crucial role in maintaining the living system, the transport capacity of the network can best be understood in terms of hydrodynamics. We report here that plasmodium from the large, single-celled amoeboid Physarum was able to construct a hydrodynamically optimized vein-network when evacuating biomass from confined arenas of various shapes through a narrow exit. Increasingly thick veins developed towards the exit, and the network spanned the arena via repetitive bifurcations to give a branching tree. The Hausdorff distance from all parts of the plasmodium to the vein network was kept low, whilst the hydrodynamic conductivity from distal parts of the network to the exit was equivalent, irrespective of the arena shape. This combination of spatial patterning and differential vein thickening served to evacuate biomass at an equivalent rate across the entire arena. The scaling relationship at the vein branches was determined experimentally to be 2.53-3.29, consistent with predictions from Murray’s law. Furthermore, we show that mathematical models for self-organised, adaptive transport in Physarum simulate the experimental network organisation well if the scaling coefficient of the current-reinforcement rule is set to 3. In simulations, this resulted in rapid development of an optimal network that minimised the combined volume and frictional energy in comparison with other scaling coefficients. This would predict that the boundary shear forces within each vein are constant throughout the network, and would be consistent with a feedback mechanism based on a sensing a threshold shear at the vein wall.

  4. Evolutionary triplet models of structured RNA.

    Directory of Open Access Journals (Sweden)

    Robert K Bradley

    2009-08-01

    Full Text Available The reconstruction and synthesis of ancestral RNAs is a feasible goal for paleogenetics. This will require new bioinformatics methods, including a robust statistical framework for reconstructing histories of substitutions, indels and structural changes. We describe a "transducer composition" algorithm for extending pairwise probabilistic models of RNA structural evolution to models of multiple sequences related by a phylogenetic tree. This algorithm draws on formal models of computational linguistics as well as the 1985 protosequence algorithm of David Sankoff. The output of the composition algorithm is a multiple-sequence stochastic context-free grammar. We describe dynamic programming algorithms, which are robust to null cycles and empty bifurcations, for parsing this grammar. Example applications include structural alignment of non-coding RNAs, propagation of structural information from an experimentally-characterized sequence to its homologs, and inference of the ancestral structure of a set of diverged RNAs. We implemented the above algorithms for a simple model of pairwise RNA structural evolution; in particular, the algorithms for maximum likelihood (ML alignment of three known RNA structures and a known phylogeny and inference of the common ancestral structure. We compared this ML algorithm to a variety of related, but simpler, techniques, including ML alignment algorithms for simpler models that omitted various aspects of the full model and also a posterior-decoding alignment algorithm for one of the simpler models. In our tests, incorporation of basepair structure was the most important factor for accurate alignment inference; appropriate use of posterior-decoding was next; and fine details of the model were least important. Posterior-decoding heuristics can be substantially faster than exact phylogenetic inference, so this motivates the use of sum-over-pairs heuristics where possible (and approximate sum-over-pairs. For more exact

  5. Structure of the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Langacker, Paul [Pennsylvania Univ., PA (United States). Dept. of Physics

    1996-07-01

    This lecture presents the structure of the standard model, approaching the following aspects: the standard model Lagrangian, spontaneous symmetry breaking, gauge interactions, covering charged currents, quantum electrodynamics, the neutral current and gauge self-interactions, and problems with the standard model, such as gauge, fermion, Higgs and hierarchy, strong C P and graviton problems.

  6. Modelling of retention of pesticides in reversed-phase high-performance liquid chromatography: Quantitative structure-retention relationships based on solute quantum-chemical descriptors and experimental (solvatochromic and spin-probe) mobile phase descriptors

    International Nuclear Information System (INIS)

    D'Archivio, Angelo Antonio; Ruggieri, Fabrizio; Mazzeo, Pietro; Tettamanti, Enzo

    2007-01-01

    A quantitative structure-retention relationship (QSRR) analysis based on multilinear regression (MLR) and artificial neural networks (ANNs) is carried out to model the combined effect of solute structure and eluent composition on the retention behaviour of pesticides in isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). The octanol-water partition coefficient and four quantum chemical descriptors (the total dipole moment, the mean polarizability, the anisotropy of the polarizability and a descriptor of hydrogen-bonding based on the atomic charges on acidic and basic chemical functionalities) are considered as solute descriptors. In order to identify suitable mobile phase descriptors, encoding composition-dependent properties of both methanol- and acetonitrile-containing mobile phases, the Kamlet-Taft solvatochromic parameters (polarity-dipolarity, hydrogen-bond acidity and hydrogen-bond basicity, π * , α and β, respectively) and the 14 N hyperfine-splitting constant (a N ) of a spin-probe dissolved in the eluent are examined. A satisfactory description of mobile phase properties influencing the solute retention is provided by a N and β or alternatively π * and β. The two seven-parameter models resulting from combination of a N and β, or π * and β, with the solute descriptors were tested on a set of 26 pesticides representative of 10 different chemical classes in a wide range of mobile phase composition (30-60% (v/v) water-methanol and 30-70% (v/v) water-acetonitrile). Within the explored experimental range, the acidity of the eluent, as quantified by α, is almost constant, and this parameter is in fact irrelevant. The results reveal that a N and π * , that can be considered as interchangeable mobile phase descriptors, are the most influent variables in the respective models. The predictive ability of the proposed models, as tested on an external data set, is quite good (Q 2 close to 0.94) when a MLR approach is used, but the

  7. Experimental and modelling studies of infiltration

    International Nuclear Information System (INIS)

    Giudici, M.

    2004-01-01

    This presentation describes a study of infiltration in the unsaturated soil with the objective of estimating the recharge to a phreatic aquifer. The study area is at the border of the city of Milan (Northern Italy), which draws water for both domestic and industrial purposes from ground water resources located beneath the urban area. The rate of water pumping from the aquifer system has been varying during the XX century, depending upon the number of inhabitants and the development of industrial activities. This caused variations with time of the depth of the water table below the ground surface and in turn some emergencies: the two most prominent episodes correspond to the middle '70s, when the water table in the city centre was about 30 m below the undisturbed natural conditions, and to the last decade, when the water table has raised at a rate of approximately 1 m/year and caused infiltrations in deep constructions (garages and building foundations, the underground railways, etc.). We have developed four ground water flow models at different scales, which share some characteristics: they are based on quasi-3D approximation (horizontal flow in the aquifers and vertical flow in the aquitards), conservative finite-differences schemes for regular grid with square cells in the horizontal plane and are implemented with proprietary computer codes. Among the problems that were studied for the development of these models, I recall some numerical problems, related to the behaviour of the phreatic aquifer under conditions of strong exploitation. Model calibration and validation for ModMil has been performed with a two-stage process, i.e., using some of the available data for model calibration and the remaining data for model validation. The application of geophysical exploration techniques, in particular seismic and geo-electrical prospecting, has been very useful to complete the data and information on the hydro-geological structure obtained from stratigraphic logs

  8. Generative models for chemical structures.

    Science.gov (United States)

    White, David; Wilson, Richard C

    2010-07-26

    We apply recently developed techniques for pattern recognition to construct a generative model for chemical structure. This approach can be viewed as ligand-based de novo design. We construct a statistical model describing the structural variations present in a set of molecules which may be sampled to generate new structurally similar examples. We prevent the possibility of generating chemically invalid molecules, according to our implicit hydrogen model, by projecting samples onto the nearest chemically valid molecule. By populating the input set with molecules that are active against a target, we show how new molecules may be generated that will likely also be active against the target.

  9. Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study

    Directory of Open Access Journals (Sweden)

    Szarf Krzysztof

    2015-02-01

    Full Text Available The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods. Moreover, Discrete Element approach is able to provide information about the grain-grain and grain-structure interactions at the microscale. This paper presents numerical and experimental investigations of flexible buried pipe behaviour with focus placed on load transfer above the buried structure. Numerical modeling was able to reproduce the experimental results. Load repartition was observed, being affected by a number of factors such as particle shape, pipe friction and pipe stiffness.

  10. Creating New Structures for Marketing Firms: An Experimental Conjoint Study

    NARCIS (Netherlands)

    Kalogeras, N.; Lans, van der I.A.C.M.; Pennings, J.M.E.; Dijk, van G.

    2004-01-01

    ABSTRACT As market conditions change rapidly in the 21st century, questions are arising concerning the suitable organizational structures and processes to meet the challenges that these conditions pose. This paper introduces a new model to structure marketing co-operatives (MCs), which is based on

  11. Temporal structures in shell models

    DEFF Research Database (Denmark)

    Okkels, F.

    2001-01-01

    The intermittent dynamics of the turbulent Gledzer, Ohkitani, and Yamada shell-model is completely characterized by a single type of burstlike structure, which moves through the shells like a front. This temporal structure is described by the dynamics of the instantaneous configuration of the shell...

  12. Pneumatic Adaptive Absorber: Mathematical Modelling with Experimental Verification

    Directory of Open Access Journals (Sweden)

    Grzegorz Mikułowski

    2016-01-01

    Full Text Available Many of mechanical energy absorbers utilized in engineering structures are hydraulic dampers, since they are simple and highly efficient and have favourable volume to load capacity ratio. However, there exist fields of applications where a threat of toxic contamination with the hydraulic fluid contents must be avoided, for example, food or pharmacy industries. A solution here can be a Pneumatic Adaptive Absorber (PAA, which is characterized by a high dissipation efficiency and an inactive medium. In order to properly analyse the characteristics of a PAA, an adequate mathematical model is required. This paper proposes a concept for mathematical modelling of a PAA with experimental verification. The PAA is considered as a piston-cylinder device with a controllable valve incorporated inside the piston. The objective of this paper is to describe a thermodynamic model of a double chamber cylinder with gas migration between the inner volumes of the device. The specific situation considered here is that the process cannot be defined as polytropic, characterized by constant in time thermodynamic coefficients. Instead, the coefficients of the proposed model are updated during the analysis. The results of the experimental research reveal that the proposed mathematical model is able to accurately reflect the physical behaviour of the fabricated demonstrator of the shock absorber.

  13. Modeling of creep for structural analysis

    Energy Technology Data Exchange (ETDEWEB)

    Naumenko, K.; Altenbach, H. [Halle-Wittenberg Univ., Halle (Germany). Lehrstuhl fuer Technische Mechanik

    2007-07-01

    ''Creep Modeling for Structural Analysis'' develops methods to simulate and analyze the time-dependent changes of stress and strain states in engineering structures up to the critical stage of creep rupture. The principal subjects of creep mechanics are the formulation of constitutive equations for creep in structural materials under multi-axial stress states; the application of structural mechanics models of beams, plates, shells and three-dimensional solids and the utilization of procedures for the solution of non-linear initial-boundary value problems. The objective of this book is to review some of the classical and recently proposed approaches to the modeling of creep for structural analysis applications as well as to extend the collection of available solutions of creep problems by new, more sophisticated examples. In Chapter 1, the book discusses basic features of the creep behavior in materials and structures and presents an overview of various approaches to the modeling of creep. Chapter 2 collects constitutive models that describe creep and damage processes under multi-axial stress states. Chapter 3 deals with the application of constitutive models to the description of creep for several structural materials. Constitutive and evolution equations, response functions and material constants are presented according to recently published experimental data. In Chapter 4 the authors discuss structural mechanics problems. Governing equations of creep in three-dimensional solids, direct variational methods and time step algorithms are reviewed. Examples are presented to illustrate the application of advanced numerical methods to the structural analysis. An emphasis is placed on the development and verification of creep-damage material subroutines inside the general purpose finite element codes. (orig.)

  14. Structure refinement using precession electron diffraction tomography and dynamical diffraction: tests on experimental data.

    Science.gov (United States)

    Palatinus, Lukáš; Corrêa, Cinthia Antunes; Steciuk, Gwladys; Jacob, Damien; Roussel, Pascal; Boullay, Philippe; Klementová, Mariana; Gemmi, Mauro; Kopeček, Jaromír; Domeneghetti, M Chiara; Cámara, Fernando; Petříček, Václav

    2015-12-01

    The recently published method for the structure refinement from three-dimensional precession electron diffraction data using dynamical diffraction theory [Palatinus et al. (2015). Acta Cryst. A71, 235-244] has been applied to a set of experimental data sets from five different samples - Ni2Si, PrVO3, kaolinite, orthopyroxene and mayenite. The data were measured on different instruments and with variable precession angles. For each sample a reliable reference structure was available. A large series of tests revealed that the method provides structure models with an average error in atomic positions typically between 0.01 and 0.02 Å. The obtained structure models are significantly more accurate than models obtained by refinement using kinematical approximation for the calculation of model intensities. The method also allows a reliable determination of site occupancies and determination of absolute structure. Based on the extensive tests, an optimal set of the parameters for the method is proposed.

  15. Comparison of mixed layer models predictions with experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Faggian, P.; Riva, G.M. [CISE Spa, Divisione Ambiente, Segrate (Italy); Brusasca, G. [ENEL Spa, CRAM, Milano (Italy)

    1997-10-01

    The temporal evolution of the PBL vertical structure for a North Italian rural site, situated within relatively large agricultural fields and almost flat terrain, has been investigated during the period 22-28 June 1993 by experimental and modellistic point of view. In particular, the results about a sunny day (June 22) and a cloudy day (June 25) are presented in this paper. Three schemes to estimate mixing layer depth have been compared, i.e. Holzworth (1967), Carson (1973) and Gryning-Batchvarova models (1990), which use standard meteorological observations. To estimate their degree of accuracy, model outputs were analyzed considering radio-sounding meteorological profiles and stability atmospheric classification criteria. Besides, the mixed layer depths prediction were compared with the estimated values obtained by a simple box model, whose input requires hourly measures of air concentrations and ground flux of {sup 222}Rn. (LN)

  16. Bayesian latent variable models for the analysis of experimental psychology data.

    Science.gov (United States)

    Merkle, Edgar C; Wang, Ting

    2018-02-01

    In this paper, we address the use of Bayesian factor analysis and structural equation models to draw inferences from experimental psychology data. While such application is non-standard, the models are generally useful for the unified analysis of multivariate data that stem from, e.g., subjects' responses to multiple experimental stimuli. We first review the models and the parameter identification issues inherent in the models. We then provide details on model estimation via JAGS and on Bayes factor estimation. Finally, we use the models to re-analyze experimental data on risky choice, comparing the approach to simpler, alternative methods.

  17. Experimentally driven atomistic model of 1,2 polybutadiene

    Energy Technology Data Exchange (ETDEWEB)

    Gkourmpis, Thomas, E-mail: thomas.gkourmpis@borealisgroup.com [Polymer Science Centre, J. J. Thomson Physical Laboratory, Department of Physics, University of Reading, Reading RG6 6AF (United Kingdom); Mitchell, Geoffrey R. [Polymer Science Centre, J. J. Thomson Physical Laboratory, Department of Physics, University of Reading, Reading RG6 6AF (United Kingdom); Centre for Rapid and Sustainable Product Development, Institute Polytechnic Leiria, Marinha Grande (Portugal)

    2014-02-07

    We present an efficient method of combining wide angle neutron scattering data with detailed atomistic models, allowing us to perform a quantitative and qualitative mapping of the organisation of the chain conformation in both glass and liquid phases. The structural refinement method presented in this work is based on the exploitation of the intrachain features of the diffraction pattern and its intimate linkage with atomistic models by the use of internal coordinates for bond lengths, valence angles, and torsion rotations. Atomic connectivity is defined through these coordinates that are in turn assigned by pre-defined probability distributions, thus allowing for the models in question to be built stochastically. Incremental variation of these coordinates allows for the construction of models that minimise the differences between the observed and calculated structure factors. We present a series of neutron scattering data of 1,2 polybutadiene at the region 120–400 K. Analysis of the experimental data yields bond lengths for Cî—¸C and C î—» C of 1.54 Å and 1.35 Å, respectively. Valence angles of the backbone were found to be at 112° and the torsion distributions are characterised by five rotational states, a three-fold trans-skew± for the backbone and gauche± for the vinyl group. Rotational states of the vinyl group were found to be equally populated, indicating a largely atactic chan. The two backbone torsion angles exhibit different behaviour with respect to temperature of their trans population, with one of them adopting an almost all trans sequence. Consequently, the resulting configuration leads to a rather persistent chain, something indicated by the value of the characteristic ratio extrapolated from the model. We compare our results with theoretical predictions, computer simulations, RIS models and previously reported experimental results.

  18. An experimental and modeling study of diethyl carbonate oxidation

    KAUST Repository

    Nakamura, Hisashi

    2015-04-01

    Diethyl carbonate (DEC) is an attractive biofuel that can be used to displace petroleum-derived diesel fuel, thereby reducing CO2 and particulate emissions from diesel engines. A better understanding of DEC combustion characteristics is needed to facilitate its use in internal combustion engines. Toward this goal, ignition delay times for DEC were measured at conditions relevant to internal combustion engines using a rapid compression machine (RCM) and a shock tube. The experimental conditions investigated covered a wide range of temperatures (660-1300K), a pressure of 30bar, and equivalence ratios of 0.5, 1.0 and 2.0 in air. To provide further understanding of the intermediates formed in DEC oxidation, species concentrations were measured in a jet-stirred reactor at 10atm over a temperature range of 500-1200K and at equivalence ratios of 0.5, 1.0 and 2.0. These experimental measurements were used to aid the development and validation of a chemical kinetic model for DEC.The experimental results for ignition in the RCM showed near negative temperature coefficient (NTC) behavior. Six-membered alkylperoxy radical (RO˙2) isomerizations are conventionally thought to initiate low-temperature branching reactions responsible for NTC behavior, but DEC has no such possible 6- and 7-membered ring isomerizations. However, its molecular structure allows for 5-, 8- and 9-membered ring RO˙2 isomerizations. To provide accurate rate constants for these ring structures, ab initio computations for RO˙2⇌Q˙OOH isomerization reactions were performed. These new RO˙2 isomerization rate constants have been implemented in a chemical kinetic model for DEC oxidation. The model simulations have been compared with ignition delay times measured in the RCM near the NTC region. Results of the simulation were also compared with experimental results for ignition in the high-temperature region and for species concentrations in the jet-stirred reactor. Chemical kinetic insights into the

  19. Experimental study on the structural and mooring loads of the WEPTOS Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur Francois Serge; Kofoed, Jens Peter

    This report presents the results of an experimental study that was performed on small scale model that was a replication of the full-scale Weptos WEC intended for DanWEC. During these tests, after optimising the mooring solution, various loads were measured that occur in the structure and mooring...

  20. Injury Based on Its Study in Experimental Models

    Directory of Open Access Journals (Sweden)

    M. Mendes-Braz

    2012-01-01

    Full Text Available The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

  1. Selective experimental review of the Standard Model

    International Nuclear Information System (INIS)

    Bloom, E.D.

    1985-02-01

    Before disussing experimental comparisons with the Standard Model, (S-M) it is probably wise to define more completely what is commonly meant by this popular term. This model is a gauge theory of SU(3)/sub f/ x SU(2)/sub L/ x U(1) with 18 parameters. The parameters are α/sub s/, α/sub qed/, theta/sub W/, M/sub W/ (M/sub Z/ = M/sub W//cos theta/sub W/, and thus is not an independent parameter), M/sub Higgs/; the lepton masses, M/sub e/, Mμ, M/sub r/; the quark masses, M/sub d/, M/sub s/, M/sub b/, and M/sub u/, M/sub c/, M/sub t/; and finally, the quark mixing angles, theta 1 , theta 2 , theta 3 , and the CP violating phase delta. The latter four parameters appear in the quark mixing matrix for the Kobayashi-Maskawa and Maiani forms. Clearly, the present S-M covers an enormous range of physics topics, and the author can only lightly cover a few such topics in this report. The measurement of R/sub hadron/ is fundamental as a test of the running coupling constant α/sub s/ in QCD. The author will discuss a selection of recent precision measurements of R/sub hadron/, as well as some other techniques for measuring α/sub s/. QCD also requires the self interaction of gluons. The search for the three gluon vertex may be practically realized in the clear identification of gluonic mesons. The author will present a limited review of recent progress in the attempt to untangle such mesons from the plethora q anti q states of the same quantum numbers which exist in the same mass range. The electroweak interactions provide some of the strongest evidence supporting the S-M that exists. Given the recent progress in this subfield, and particularly with the discovery of the W and Z bosons at CERN, many recent reviews obviate the need for further discussion in this report. In attempting to validate a theory, one frequently searches for new phenomena which would clearly invalidate it. 49 references, 28 figures

  2. Hydroforming Of Patchwork Blanks — Numerical Modeling And Experimental Validation

    Science.gov (United States)

    Lamprecht, Klaus; Merklein, Marion; Geiger, Manfred

    2005-08-01

    In comparison to the commonly applied technology of tailored blanks the concept of patchwork blanks offers a number of additional advantages. Potential application areas for patchwork blanks in automotive industry are e.g. local reinforcements of automotive closures, structural reinforcements of rails and pillars as well as shock towers. But even if there is a significant application potential for patchwork blanks in automobile production, industrial realization of this innovative technique is decelerated due to a lack of knowledge regarding the forming behavior and the numerical modeling of patchwork blanks. Especially for the numerical simulation of hydroforming processes, where one part of the forming tool is replaced by a fluid under pressure, advanced modeling techniques are required to ensure an accurate prediction of the blanks' forming behavior. The objective of this contribution is to provide an appropriate model for the numerical simulation of patchwork blanks' forming processes. Therefore, different finite element modeling techniques for patchwork blanks are presented. In addition to basic shell element models a combined finite element model consisting of shell and solid elements is defined. Special emphasis is placed on the modeling of the weld seam. For this purpose the local mechanical properties of the weld metal, which have been determined by means of Martens-hardness measurements and uniaxial tensile tests, are integrated in the finite element models. The results obtained from the numerical simulations are compared to experimental data from a hydraulic bulge test. In this context the focus is laid on laser- and spot-welded patchwork blanks.

  3. Handbook of structural equation modeling

    CERN Document Server

    Hoyle, Rick H

    2012-01-01

    The first comprehensive structural equation modeling (SEM) handbook, this accessible volume presents both the mechanics of SEM and specific SEM strategies and applications. The editor, contributors, and editorial advisory board are leading methodologists who have organized the book to move from simpler material to more statistically complex modeling approaches. Sections cover the foundations of SEM; statistical underpinnings, from assumptions to model modifications; steps in implementation, from data preparation through writing the SEM report; and basic and advanced applications, inclu

  4. Experimental and theoretical evidence for the chaotic dynamics of complex structures

    International Nuclear Information System (INIS)

    Agop, M; Dimitriu, D G; Poll, E; Niculescu, O; Radu, V

    2013-01-01

    This paper presents the experimental results on the formation, dynamics and evolution towards chaos of complex space charge structures that emerge in front of a positively biased electrode immersed in a quiescent plasma. In certain experimental conditions, we managed to obtain the so-called multiple double layers (MDLs) with non-concentric configuration. Our experiments show that the interactions between each MDL's constituent entities are held responsible for the complex dynamics and eventually for its transition to chaos through cascades of spatio-temporal sub-harmonic bifurcations. Further, we build a theoretical model based on the fractal approximation (scale relativity theory) in order to reproduce the experimental results (plasma self-structuring and scenario of evolution to chaos). Comparing the experimental results with the theoretical ones, we observe a good correlation between them. (paper)

  5. Experimental validation of tape springs to be used as thin-walled space structures

    Science.gov (United States)

    Oberst, S.; Tuttle, S. L.; Griffin, D.; Lambert, A.; Boyce, R. R.

    2018-04-01

    With the advent of standardised launch geometries and off-the-shelf payloads, space programs utilising nano-satellite platforms are growing worldwide. Thin-walled, flexible and self-deployable structures are commonly used for antennae, instrument booms or solar panels owing to their lightweight, ideal packaging characteristics and near zero energy consumption. However their behaviour in space, in particular in Low Earth Orbits with continually changing environmental conditions, raises many questions. Accurate numerical models, which are often not available due to the difficulty of experimental testing under 1g-conditions, are needed to answer these questions. In this study, we present on-earth experimental validations, as a starting point to study the response of a tape spring as a representative of thin-walled flexible structures under static and vibrational loading. Material parameters of tape springs in a singly (straight, open cylinder) and a doubly curved design, are compared to each other by combining finite element calculations, with experimental laser vibrometry within a single and multi-stage model updating approach. While the determination of the Young's modulus is unproblematic, the damping is found to be inversely proportional to deployment length. With updated material properties the buckling instability margin is calculated using different slenderness ratios. Results indicate a high sensitivity of thin-walled structures to miniscule perturbations, which makes proper experimental testing a key requirement for stability prediction on thin-elastic space structures. The doubly curved tape spring provides closer agreement with experimental results than a straight tape spring design.

  6. Experimental Observation of Brachistochrone Wave Dynamics in PT Symmetric Structures

    Science.gov (United States)

    Schindler, Joseph; Ramezani, Hamidreza; Li, Ang; Zheng, Mei; Kottos, Tsampikos; Ellis, Fred

    2012-02-01

    Mutually coupled modes of a pair of active LRC circuits, one with amplification and another with an equivalent amount of attenuation, provide an experimental realization of a wide class of systems where gain and loss mechanisms break the Hermiticity while preserving parity-time (PT) symmetry. For a value γ PT of the gain and loss strength parameter the eigenfrequencies undergo a spontaneous phase transition from real to complex values, while the normal modes coalesce, acquiring a definite chirality. A dramatic manifestation of PT symmetry is observed in the brachistochrone wave dynamics. Experimental findings support the theoretical prediction of arbitrarily small energy transfer times between the LRC elements of the circuit. We envision that realization of such design strategies can have applications in telecommunications and metamaterial structures.

  7. Structures under crash and impact continuum mechanics, discretization and experimental characterization

    CERN Document Server

    Hiermaier, Stefan

    2007-01-01

    Required reading for those in the relevant areas of work, this book examines the testing and modeling of materials and structures under dynamic loading conditions.Readers get an in-depth analysis of the current mathematical modeling and simulation tools available for a variety of materials, alongside discussions of the benefits and limitations these tools pose in industrial design.The models discussed are also available in commercial codes such as LS-DYNA and AOTODYN.Following a logical and well organized structure, this volume uniquely combines experimental procedures with numerical simulatio

  8. Experimental Verification of the Structural Glass Beam-Columns Strength

    Science.gov (United States)

    Pešek, Ondřej; Melcher, Jindřich; Balázs, Ivan

    2017-10-01

    This paper deals with experimental research of axially and laterally loaded members made of structural (laminated) glass. The purpose of the research is the evaluation of buckling strength and actual behaviour of the beam-columns due to absence of standards for design of glass load-bearing structures. The experimental research follows the previous one focusing on measuring of initial geometrical imperfections of glass members, testing of glass beams and columns. Within the frame of the research 9 specimens were tested. All of them were of the same geometry (length 2000 mm, width 200 mm and thickness 16 mm) but different composition – laminated double glass made of annealed glass or fully tempered glass panes bonded together by PVB or EVASAFE foil. Specimens were at first loaded by axial force and then by constantly increasing bending moment up to failure. During testing lateral deflections, vertical deflection and normal stresses at mid-span were measured. A maximum load achieved during testing has been adopted as flexural-lateral-torsional buckling strength. The results of experiments were statistically evaluated according to the European standard for design of structures EN 1990, appendix D. There are significant differences between specimens made of annealed glass or fully tempered glass. Differences between specimens loaded by axial forces 1 kN and 2 kN are negligible. The next step was to determine the design strength by calculation procedure based on buckling curves approach intended for design of steel columns and develop interaction criterion for glass beams-columns.

  9. Classification of RNA structure change by 'gazing' at experimental data.

    Science.gov (United States)

    Woods, Chanin Tolson; Laederach, Alain

    2017-06-01

    Mutations (or Single Nucleotide Variants) in folded RiboNucleic Acid structures that cause local or global conformational change are riboSNitches. Predicting riboSNitches is challenging, as it requires making two, albeit related, structure predictions. The data most often used to experimentally validate riboSNitch predictions is Selective 2' Hydroxyl Acylation by Primer Extension, or SHAPE. Experimentally establishing a riboSNitch requires the quantitative comparison of two SHAPE traces: wild-type (WT) and mutant. Historically, SHAPE data was collected on electropherograms and change in structure was evaluated by 'gel gazing.' SHAPE data is now routinely collected with next generation sequencing and/or capillary sequencers. We aim to establish a classifier capable of simulating human 'gazing' by identifying features of the SHAPE profile that human experts agree 'looks' like a riboSNitch. We find strong quantitative agreement between experts when RNA scientists 'gaze' at SHAPE data and identify riboSNitches. We identify dynamic time warping and seven other features predictive of the human consensus. The classSNitch classifier reported here accurately reproduces human consensus for 167 mutant/WT comparisons with an Area Under the Curve (AUC) above 0.8. When we analyze 2019 mutant traces for 17 different RNAs, we find that features of the WT SHAPE reactivity allow us to improve thermodynamic structure predictions of riboSNitches. This is significant, as accurate RNA structural analysis and prediction is likely to become an important aspect of precision medicine. The classSNitch R package is freely available at http://classsnitch.r-forge.r-project.org . alain@email.unc.edu. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press.

  10. Experimentally Induced Mammalian Models of Glaucoma

    Directory of Open Access Journals (Sweden)

    Makoto Ishikawa

    2015-01-01

    Full Text Available A wide variety of animal models have been used to study glaucoma. Although these models provide valuable information about the disease, there is still no ideal model for studying glaucoma due to its complex pathogenesis. Animal models for glaucoma are pivotal for clarifying glaucoma etiology and for developing novel therapeutic strategies to halt disease progression. In this review paper, we summarize some of the major findings obtained in various glaucoma models and examine the strengths and limitations of these models.

  11. Probabilistic models for structured sparsity

    DEFF Research Database (Denmark)

    Andersen, Michael Riis

    of each time series is decomposed into a non-negative linear combination of elements from a dictionary of shared covariance matrix components. A variational Bayes algorithm is derived for approximate posterior inference. The proposed model is validated using a functional magnetic resonance imaging (f......Sparsity has become an increasingly popular choice of regularization in machine learning and statistics. The sparsity assumption for a matrixX means that most of the entries in X are equal to exactly zero. Structured sparsity is generalization of sparsity and assumes that the set of locations...... of the non-zero coefficients in X contains structure that can be exploited. This thesis deals with probabilistic models for structured sparsity for regularization of ill-posed problems. The aim of the thesis is two-fold; to construct sparsity promoting prior distributions for structured sparsity...

  12. Seismic vulnerability of the Himalayan half-dressed rubble stone masonry structures, experimental and analytical studies

    Directory of Open Access Journals (Sweden)

    N. Ahmad

    2012-11-01

    Full Text Available Half-Dressed rubble stone (DS masonry structures as found in the Himalayan region are investigated using experimental and analytical studies. The experimental study included a shake table test on a one-third scaled structural model, a representative of DS masonry structure employed for public critical facilities, e.g. school buildings, offices, health care units, etc. The aim of the experimental study was to understand the damage mechanism of the model, develop damage scale towards deformation-based assessment and retrieve the lateral force-deformation response of the model besides its elastic dynamic properties, i.e. fundamental vibration period and elastic damping. The analytical study included fragility analysis of building prototypes using a fully probabilistic nonlinear dynamic method. The prototypes are designed as SDOF systems assigned with lateral, force-deformation constitutive law (obtained experimentally. Uncertainties in the constitutive law, i.e. lateral stiffness, strength and deformation limits, are considered through random Monte Carlo simulation. Fifty prototype buildings are analyzed using a suite of ten natural accelerograms and an incremental dynamic analysis technique. Fragility and vulnerability functions are derived for the damageability assessment of structures, economic loss and casualty estimation during an earthquake given the ground shaking intensity, essential within the context of risk assessment of existing stock aiming towards risk mitigation and disaster risk reduction.

  13. Modelling and Experimental Investigation of an Active Damper

    Directory of Open Access Journals (Sweden)

    Rafael Luís Teixeira

    2006-01-01

    Full Text Available This paper presents a validation methodology of the dynamic behavior of an active viscous damper. The damper has two flexible metallic bellows connected to a rigid reservoir filled with fluid. When one of the bellows is connected to a vibrating structure a periodic flow passes through a variable internal orifice and the damping effect is produced. The size of the orifice is adjusted by a controlled linear piezoelectric actuator that positions the conical core into a conical cavity. The device finite element structural model consists of the valve body and its conical core that are assumed rigid and the flexible bellows are represented by two pistons with elastic suspensions. The flow developed inside the damper is modeled considering the fluid-structure interation, using the Lagrangean-Eulerian formulation. To validate the proposed model a prototype was constructed and experimental tests and numerical simulations are accomplished in the time domain, applying harmonic excitations. The results are compared using curves that relate the damping coefficient with the orifice size and with the input velocity applied at the bellows face. However, for the proper control design and system operation, the direct use of the finite element model becomes unviable due to its high computational time. Then, a reduced second order discrete dynamic model for the damper was developed. The model parameters are identified by analysis in the frequency domain, using impulsive excitation force, for constant and variable orifice sizes. At low excitation frequencies, the damper prototype behaves like a single degree of freedom system which damping factor changes with the orifice size A fuzzy controller was designed and it generates the orifice reference size associated to the desired damping factor. The active system presented better performance when compared to the passive one.

  14. A QM/MM refinement of an experimental DNA structure with metal-mediated base pairs.

    Science.gov (United States)

    Kumbhar, Sadhana; Johannsen, Silke; Sigel, Roland K O; Waller, Mark P; Müller, Jens

    2013-10-01

    A series of hybrid quantum mechanical/molecular mechanical (QM/MM) calculations was performed on models of a DNA duplex with artificial silver(I)-mediated imidazole base pairs. The optimized structures were compared to the original experimental NMR structure (Nat. Chem. 2 (2010) 229-234). The metal⋯metal distances are significantly shorter (~0.5Å) in the QM/MM model than in the original NMR structure. As a result, argentophilic interactions are feasible between the silver(I) ions of neighboring metal-mediated base pairs. Using the computationally determined metal⋯metal distances, a re-refined NMR solution structure of the DNA duplex was obtained. In this new NMR structure, all experimental constraints remain fulfilled. The new NMR structure shows less deviation from the regular B-type conformation than the original one. This investigation shows that the application of QM/MM models to generate additional constraints to be used during NMR structural refinements represents an elegant approach to obtaining high-resolution NMR structures. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Experimental Active Vibration Control in Truss Structures Considering Uncertainties in System Parameters

    Directory of Open Access Journals (Sweden)

    Douglas Domingues Bueno

    2008-01-01

    Full Text Available This paper deals with the study of algorithms for robust active vibration control in flexible structures considering uncertainties in system parameters. It became an area of enormous interest, mainly due to the countless demands of optimal performance in mechanical systems as aircraft, aerospace, and automotive structures. An important and difficult problem for designing active vibration control is to get a representative dynamic model. Generally, this model can be obtained using finite element method (FEM or an identification method using experimental data. Actuators and sensors may affect the dynamics properties of the structure, for instance, electromechanical coupling of piezoelectric material must be considered in FEM formulation for flexible and lightly damping structure. The nonlinearities and uncertainties involved in these structures make it a difficult task, mainly for complex structures as spatial truss structures. On the other hand, by using an identification method, it is possible to obtain the dynamic model represented through a state space realization considering this coupling. This paper proposes an experimental methodology for vibration control in a 3D truss structure using PZT wafer stacks and a robust control algorithm solved by linear matrix inequalities.

  16. Dynamic vehicle model for handling performance using experimental data

    Directory of Open Access Journals (Sweden)

    SangDo Na

    2015-11-01

    Full Text Available An analytical vehicle model is essential for the development of vehicle design and performance. Various vehicle models have different complexities, assumptions and limitations depending on the type of vehicle analysis. An accurate full vehicle model is essential in representing the behaviour of the vehicle in order to estimate vehicle dynamic system performance such as ride comfort and handling. An experimental vehicle model is developed in this article, which employs experimental kinematic and compliance data measured between the wheel and chassis. From these data, a vehicle model, which includes dynamic effects due to vehicle geometry changes, has been developed. The experimental vehicle model was validated using an instrumented experimental vehicle and data such as a step change steering input. This article shows a process to develop and validate an experimental vehicle model to enhance the accuracy of handling performance, which comes from precise suspension model measured by experimental data of a vehicle. The experimental force data obtained from a suspension parameter measuring device are employed for a precise modelling of the steering and handling response. The steering system is modelled by a lumped model, with stiffness coefficients defined and identified by comparing steering stiffness obtained by the measured data. The outputs, specifically the yaw rate and lateral acceleration of the vehicle, are verified by experimental results.

  17. Experimental demonstration of dielectric structure based two beam acceleration

    International Nuclear Information System (INIS)

    Gai, W.; Conde, M. E.; Konecny, R.; Power, J. G.; Schoessow, P.; Sun, X.; Zou, P.

    2000-01-01

    We report on the experimental results of the dielectric based two beam accelerator (step-up transformer). By using a single high charge beam, we have generated and extracted a high power RF pulse from a 7.8 GHz primary dielectric structure and then subsequently transferred to a second accelerating structure with higher dielectric constant and smaller transverse dimensions. We have measured the energy change of a second (witness) beam passing through the acceleration stage. The measured gradient is >4 times the deceleration gradient. The detailed experiment of set-up and results of the measurements are dimmed. Future plans for the development of a 100 MeV demonstration accelerator based on this technique is presented

  18. Modeling Fission Product Sorption in Graphite Structures

    International Nuclear Information System (INIS)

    Szlufarska, Izabela; Morgan, Dane; Allen, Todd

    2013-01-01

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high-temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission products

  19. Modeling Fission Product Sorption in Graphite Structures

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [University of Wisconsin, Madison, WI (United States); Morgan, Dane [University of Wisconsin, Madison, WI (United States); Allen, Todd [University of Wisconsin, Madison, WI (United States)

    2013-04-08

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high- temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission

  20. Experimental force modeling for deformation machining stretching ...

    Indian Academy of Sciences (India)

    Deformation machining is a hybrid process that combines two manufacturing processes—thin structure machining and single-point incremental forming. This process enables the creation of complex structures and geometries, which would be rather difficult or sometimes impossible to manufacture. A comprehensive ...

  1. Experimental force modeling for deformation machining stretching ...

    Indian Academy of Sciences (India)

    ARSHPREET SINGH

    Deformation machining is a hybrid process that combines two manufacturing processes—thin structure machining and ... structures and geometries, which would be rather difficult or sometimes impossible to manufacture. A com- prehensive ... sheet metal is deformed locally into plastic stage, enabling creation of complex ...

  2. Modeling and experimental characterization of stepped and v-shaped (311) defects in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Marqués, Luis A., E-mail: lmarques@ele.uva.es; Aboy, María [Departamento de Electrónica, Universidad de Valladolid, E.T.S.I. de Telecomunicación, 47011 Valladolid (Spain); Dudeck, Karleen J.; Botton, Gianluigi A. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Knights, Andrew P. [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Gwilliam, Russell M. [Surrey Ion Beam Centre, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2014-04-14

    We propose an atomistic model to describe extended (311) defects in silicon. It is based on the combination of interstitial and bond defect chains. The model is able to accurately reproduce not only planar (311) defects but also defect structures that show steps, bends, or both. We use molecular dynamics techniques to show that these interstitial and bond defect chains spontaneously transform into extended (311) defects. Simulations are validated by comparing with precise experimental measurements on actual (311) defects. The excellent agreement between the simulated and experimentally derived structures, regarding individual atomic positions and shape of the distinct structural (311) defect units, provides strong evidence for the robustness of the proposed model.

  3. Thermal Effects Modeling Developed for Smart Structures

    Science.gov (United States)

    Lee, Ho-Jun

    1998-01-01

    Applying smart materials in aeropropulsion systems may improve the performance of aircraft engines through a variety of vibration, noise, and shape-control applications. To facilitate the experimental characterization of these smart structures, researchers have been focusing on developing analytical models to account for the coupled mechanical, electrical, and thermal response of these materials. One focus of current research efforts has been directed toward incorporating a comprehensive thermal analysis modeling capability. Typically, temperature affects the behavior of smart materials by three distinct mechanisms: Induction of thermal strains because of coefficient of thermal expansion mismatch 1. Pyroelectric effects on the piezoelectric elements; 2. Temperature-dependent changes in material properties; and 3. Previous analytical models only investigated the first two thermal effects mechanisms. However, since the material properties of piezoelectric materials generally vary greatly with temperature (see the graph), incorporating temperature-dependent material properties will significantly affect the structural deflections, sensory voltages, and stresses. Thus, the current analytical model captures thermal effects arising from all three mechanisms through thermopiezoelectric constitutive equations. These constitutive equations were incorporated into a layerwise laminate theory with the inherent capability to model both the active and sensory response of smart structures in thermal environments. Corresponding finite element equations were formulated and implemented for both the beam and plate elements to provide a comprehensive thermal effects modeling capability.

  4. A stochastic method for asphaltene structure formulation from experimental data: avoidance of implausible structures.

    Science.gov (United States)

    De León, Jennifer; Velásquez, Ana M; Hoyos, Bibian A

    2017-04-12

    This work presents a stochastic procedure designed to formulate a discrete set of molecular structures that, as a whole, adjust properly to experimental asphaltene data. This algorithm incorporates the pentane effect concept and Clar's sextet rule to the formulation process. The set of viable structures was constructed based on probability distribution functions obtained from experimental information and an isomer database containing all plausible configurations for a given number of rings, avoiding high-energy structures. This procedure was applied to a collection of experimental data from the literature. Ten sets, consisting of 5000 structures each, were obtained. Each set was then optimized. For the most accurate representation, four molecules were sufficient to properly reproduce the experimental input. The asphaltene system obtained is consistent with the reported molecular weight, number of aromatic rings and heteroatom content. Molecular dynamic simulations showed that the asphaltene representation adequately reproduced asphaltene aggregation behavior in toluene and n-heptane. In toluene, a single three-molecule aggregate was observed, and the majority of asphaltene molecules remained in a monomeric state. In n-heptane, aggregates containing up to four molecules were observed; both porous and compact aggregates were found. The asphaltene molecular representation obtained, which allows researchers to avoid inappropriate torsions in the molecule, is able to reproduce interplanar distances between aromatic cores of 4 Å or less for the aggregation state, as supported by experimental results.

  5. Septic arthritis: immunopathogenesis, experimental models and therapy

    Science.gov (United States)

    2014-01-01

    Septic arthritis is an inflammatory disease of the joints that is started by an infection whose most common agent is Staphylococcus aureus. In this review we discuss some of the most arthritogenic bacterial factors and the contribution of innate and specific immune mechanisms to joint destruction. Special emphasis is given to the induction of experimental arthritis by S. aureus in mice. The improvement of therapy by association of antibiotics with down-modulation of immunity is also included. PMID:24822058

  6. Experimental validation of 3D printed material behaviors and their influence on the structural topology design

    Science.gov (United States)

    Yang, Kai Ke; Zhu, Ji Hong; Wang, Chuang; Jia, Dong Sheng; Song, Long Long; Zhang, Wei Hong

    2018-02-01

    The purpose of this paper is to investigate the structures achieved by topology optimization and their fabrications by 3D printing considering the particular features of material microstructures and macro mechanical performances. Combining Digital Image Correlation and Optical Microscope, this paper experimentally explored the anisotropies of stiffness and strength existing in the 3D printed polymer material using Stereolithography (SLA) and titanium material using Selective Laser Melting (SLM). The standard specimens and typical structures obtained by topology optimization were fabricated along different building directions. On the one hand, the experimental results of these SLA produced structures showed stable properties and obviously anisotropic rules in stiffness, ultimate strengths and places of fractures. Further structural designs were performed using topology optimization when the particular mechanical behaviors of SLA printed materials were considered, which resulted in better structural performances compared to the optimized designs using `ideal' isotropic material model. On the other hand, this paper tested the mechanical behaviors of SLM printed multiscale lattice structures which were fabricated using the same metal powder and the same machine. The structural stiffness values are generally similar while the strength behaviors show a difference, which are mainly due to the irregular surface quality of the tiny structural branches of the lattice. The above evidences clearly show that the consideration of the particular behaviors of 3D printed materials is therefore indispensable for structural design and optimization in order to improve the structural performance and strengthen their practical significance.

  7. Experimental comparison of models for ultrafast impact ionization is silicon

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Iwaszczuk, Krzysztof; Jepsen, Peter Uhd

    2016-01-01

    We compare experimentally the exponential and quadratic (Keldysh formula) impact ionization models using THz induced impact ionization in silicon. We demonstrate that the exponential model offers the best description of impact ionization process for ultrashort electric filed pulses....

  8. Experimental validation of Swy-2 clay standard's PHREEQC model

    Science.gov (United States)

    Szabó, Zsuzsanna; Hegyfalvi, Csaba; Freiler, Ágnes; Udvardi, Beatrix; Kónya, Péter; Székely, Edit; Falus, György

    2017-04-01

    reactions under the studied conditions and increased reactivity in presence of scCO2. A model sensitivity analysis has pointed out that the continuously changing solution composition results cannot be described by the change of the uncertain reactive surface area of mineral phases in the model and still several orders of magnitude different ion-concentrations are predicted. However, by considering the clay standard's cation exchange capacity divided proportionally among interlayer cations of Na-montmorillonite, the measured variation can be described on an order of magnitude level. It is furthermore indicated that not only the interlayer cations take part in this process but a minor proportion of other, structural ions as well, differently in the reference and scCO2 environments. Experimental methodological aspects of the work, such as solution sampling, solid sample post-experimental treatment, solution and solid sample analysis sensitivity, expected experimental by-products etc. are also to be addressed.

  9. Mechanical Model Development for Composite Structural Supercapacitors

    Science.gov (United States)

    Ricks, Trenton M.; Lacy, Thomas E., Jr.; Santiago, Diana; Bednarcyk, Brett A.

    2016-01-01

    Novel composite structural supercapacitor concepts have recently been developed as a means both to store electrical charge and to provide modest mechanical load carrying capability. Double-layer composite supercapacitors are often fabricated by impregnating a woven carbon fiber fabric, which serves as the electrodes, with a structural polymer electrolyte. Polypropylene or a glass fabric is often used as the separator material. Recent research has been primarily limited to evaluating these composites experimentally. In this study, mechanical models based on the Multiscale Generalized Method of Cells (MSGMC) were developed and used to calculate the shear and tensile properties and response of two composite structural supercapacitors from the literature. The modeling approach was first validated against traditional composite laminate data. MSGMC models for composite supercapacitors were developed, and accurate elastic shear/tensile properties were obtained. It is envisioned that further development of the models presented in this work will facilitate the design of composite components for aerospace and automotive applications and can be used to screen candidate constituent materials for inclusion in future composite structural supercapacitor concepts.

  10. Modeling and experimental diagnostics in polymer electrolyte fuel cells

    Science.gov (United States)

    Springer, T. E.; Wilson, M. S.; Gottesfeld, S.

    1993-12-01

    This paper presents a fit between model and experiments for well-humidified polymer electrolyte fuel cells operated to maximum current density with a range of cathode gas compositions. The model considers, in detail, losses caused by: (1) interfacial kinetics at the Pt/ionomer interface; (2) gas-transport and ionic-conductivity limitations in the catalyst layer; and (3) gas-transport limitations in the cathode backing. Our experimental data were collected with cells that utilized thin-film catalyst layers bonded directly to the membrane, and a separate catalyst-free hydrophobic backing layer. This structure allows a clearer resolution of the processes taking place in each of these distinguishable parts of the cathode. In our final comparison of model predictions with the experimental data, we stress the simultaneous fit of a family of complete polarization curves obtained for gas compositions ranging from 5 atoms O2 to a mixture of 5% O2 in N2, employing in each case the same model parameters for interracial kinetics, catalyst-layer transport, and backing-layer transport. This approach allowed us to evaluate losses in the cathode backing and in the cathode catalyst layer, and thus identify the improvements required to enhance the performance of air cathodes in polymer electrolyte fuel cells. Finally, we show that effects of graded depletion in oxygen along the gas flow channel can be accurately modeled using a uniform effective oxygen concentration in the flow channel, equal to the average of inlet and exit concentrations. This approach has enabled simplified and accurate consideration of oxygen utilization effects.

  11. Experimental Studies on Damage Detection in Frame Structures Using Vibration Measurements

    Directory of Open Access Journals (Sweden)

    Giancarlo Fraraccio

    2010-01-01

    Full Text Available This paper presents an experimental study of frequency and time domain identification algorithms and discusses their effectiveness in structural health monitoring of frame structures using acceleration input and response data. Three algorithms were considered: 1 a frequency domain decomposition algorithm (FDD, 2 a time domain Observer Kalman IDentification algorithm (OKID, and 3 a subsequent physical parameter identification algorithm (MLK. Through experimental testing of a four-story steel frame model on a uniaxial shake table, the inherent complications of physical instrumentation and testing are explored. Primarily, this study aims to provide a dependable first-order and second-order identification of said test structure in a fully instrumented state. Once the characteristics (i.e. the stiffness matrix for a benchmark structure have been determined, structural damage can be detected by a change in the identified structural stiffness matrix. This work also analyzes the stability of the identified structural stiffness matrix with respect to fluctuations of input excitation magnitude and frequency content in an experimental setting.

  12. Preliminary Results on the Experimental Investigation of the Structure Functions of Bound Nucleons

    Energy Technology Data Exchange (ETDEWEB)

    Bodek, Arie [Univ. of Rochester, NY (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-08-01

    We present preliminary results on an experimental study of the nuclear modification of the longitudinal ($\\sigma_L$) and transverse ($\\sigma_T$) structure functions of nucleons bound in nuclear targets. The origin of these modifications (commonly referred as as the EMC effect) is not fully understood. Our measurements of R= $\\sigma_L / \\sigma_T$ for nuclei ($R_A$) and for deuterium ($R_D$) indicate that nuclear modifications of the structure functions of bound nucleons are different for the longitudinal and transverse structure functions, and that contrary to expectation from several theoretical models, $R_A< R_D$.

  13. Modeling RNA secondary structure folding ensembles using SHAPE mapping data.

    Science.gov (United States)

    Spasic, Aleksandar; Assmann, Sarah M; Bevilacqua, Philip C; Mathews, David H

    2018-01-09

    RNA secondary structure prediction is widely used for developing hypotheses about the structures of RNA sequences, and structure can provide insight about RNA function. The accuracy of structure prediction is known to be improved using experimental mapping data that provide information about the pairing status of single nucleotides, and these data can now be acquired for whole transcriptomes using high-throughput sequencing. Prior methods for using these experimental data focused on predicting structures for sequences assuming that they populate a single structure. Most RNAs populate multiple structures, however, where the ensemble of strands populates structures with different sets of canonical base pairs. The focus on modeling single structures has been a bottleneck for accurately modeling RNA structure. In this work, we introduce Rsample, an algorithm for using experimental data to predict more than one RNA structure for sequences that populate multiple structures at equilibrium. We demonstrate, using SHAPE mapping data, that we can accurately model RNA sequences that populate multiple structures, including the relative probabilities of those structures. This program is freely available as part of the RNAstructure software package. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  14. Cryogenic structures of superconducting coils for fusion experimental reactor 'ITER'

    International Nuclear Information System (INIS)

    Nakajima, Hideo; Iguchi, Masahide; Hamada, Kazuya; Okuno, Kiyoshi; Takahashi, Yoshikazu; Shimamoto, Susumu

    2013-01-01

    This paper describes both structural materials and structural design of the Toroidal Field (TF) coil and Central Solenoid (CS) for the International Thermonuclear Experimental Reactor (ITER). All the structural materials used in the superconducting coil system of the ITER are austenitic stainless steels. Although 316LN is used in the most parts of the superconducting coil system, the cryogenic stainless steels, JJ1 and JK2LB, which were newly developed by the Japan Atomic Energy Agency (JAEA) and Japanese steel companies, are used in the highest stress area of the TF coil case and the whole CS conductor jackets, respectively. These two materials became commercially available based on demonstration of productivity and weldability of materials, and evaluations of 4 K mechanical properties of trial products including welded parts. Structural materials are classified into five grades depending on stress distribution in the TF coil case. JAEA made an industrial specification for mass production based on the ITER requirements. In order to simplify quality control in mass production, JAEA has used materials specified in the material section of 'Codes for Fusion Facilities - Rules on Superconducting Magnet Structure (2008)' issued by the Japan Society of Mechanical Engineers (JSME) in October 2008, which was established using an extrapolation method of 4 K material strengths from room temperature strength and chemical compositions developed by JAEA. It enables steel suppliers to easily control the quality of products at room temperature. JAEA has already started actual production with several manufacturing companies. The first JJ1 product to be used in the TF coil case and the first JK2LB jackets for CS were completed in October and September 2013, respectively. (author)

  15. Numerical model updating technique for structures using firefly algorithm

    Science.gov (United States)

    Sai Kubair, K.; Mohan, S. C.

    2018-03-01

    Numerical model updating is a technique used for updating the existing experimental models for any structures related to civil, mechanical, automobiles, marine, aerospace engineering, etc. The basic concept behind this technique is updating the numerical models to closely match with experimental data obtained from real or prototype test structures. The present work involves the development of numerical model using MATLAB as a computational tool and with mathematical equations that define the experimental model. Firefly algorithm is used as an optimization tool in this study. In this updating process a response parameter of the structure has to be chosen, which helps to correlate the numerical model developed with the experimental results obtained. The variables for the updating can be either material or geometrical properties of the model or both. In this study, to verify the proposed technique, a cantilever beam is analyzed for its tip deflection and a space frame has been analyzed for its natural frequencies. Both the models are updated with their respective response values obtained from experimental results. The numerical results after updating show that there is a close relationship that can be brought between the experimental and the numerical models.

  16. Experimental evaluation of the structural behaviour of adobe masonry structural elements

    OpenAIRE

    Varum, H.; Costa, A.; Pereira, H.; Almeida, J.; Rodrigues, H.; Silveira, D.

    2007-01-01

    Rehabilitation and strengthening of existing adobe masonry constructions have been neglected during the last decades. In Aveiro, Portugal, many adobe buildings present an important level of structural damage and, in many cases, are even near to ruin, having the majority a high vulnerability to seismic actions. To face the lack of information concerning the mechanical properties and structural behaviour of adobe elements, it was developed an experimental campaign. The composition and mechanica...

  17. Experimental study on mechanical properties of aircraft honeycomb sandwich structures

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available Mechanical behaviour of sandwich panels under different conditions have been exprimentally studied in this research to increase the knowledge of aircraft sandwich panel structures and facilitate design criteria for aircraft structures. Tests were concentrated on the honeycomb sandwich structures under different loads including flexural, insert shear, flat wise tension and compression loads. Furthermore, effect of core density and face material on mechanical behavior of different samples were investigated and compared with analytical and FEM method. Effects of skin thickness on strength of honycomb sandwhich panels under shear pull out and moments have also been considerd in this study. According to this investigation, insert strength and flexural test under different load conditions is strongly affected by face thickness, but compression and tearoff (falt wise tensile properties of a sandwich panel depends on core material. The study concludes that the correlation between experimental results and the analytical predictions will enable the designer to predict the mechanical behaviour and strength of a sandwich beam; however, applied formula may lead engineers to unreliable results for shear modulus.

  18. The experimental search for new predicted binary-alloy structures

    Science.gov (United States)

    Erb, K. C.; Richey, Lauren; Lang, Candace; Campbell, Branton; Hart, Gus

    2010-10-01

    Predicting new ordered phases in metallic alloys is a productive line of inquiry because configurational ordering in an alloy can dramatically alter their useful material properties. One is able to infer the existence of an ordered phase in an alloy using first-principles calculated formation enthalpies.ootnotetextG. L. W. Hart, ``Where are Nature's missing structures?,'' Nature Materials 6 941-945 2007 Using this approach, we have been able to identify stable (i.e. lowest energy) orderings in a variety of binary metallic alloys. Many of these phases have been observed experimentally in the past, though others have not. In pursuit of several of the missing structures, we have characterized potential orderings in PtCd, PtPd and PtMo alloys using synchrotron x-ray powder diffraction and symmetry-analysis tools.ootnotetextB. J. Campbell, H. T. Stokes, D. E. Tanner, and D. M. Hatch, ``ISODISPLACE: a web-based tool for exploring structural distortions,'' J. Appl. Cryst. 39, 607-614 (2006)

  19. Deriving Structural Information from Experimentally Measured Data on Biomolecules.

    Science.gov (United States)

    van Gunsteren, Wilfred F; Allison, Jane R; Daura, Xavier; Dolenc, Jožica; Hansen, Niels; Mark, Alan E; Oostenbrink, Chris; Rusu, Victor H; Smith, Lorna J

    2016-12-23

    During the past half century, the number and accuracy of experimental techniques that can deliver values of observables for biomolecular systems have been steadily increasing. The conversion of a measured value Q exp of an observable quantity Q into structural information is, however, a task beset with theoretical and practical problems: 1) insufficient or inaccurate values of Q exp , 2) inaccuracies in the function Q(r→) used to relate the quantity Q to structure r→ , 3) how to account for the averaging inherent in the measurement of Q exp , 4) how to handle the possible multiple-valuedness of the inverse r→(Q) of the function Q(r→) , to mention a few. These apply to a variety of observable quantities Q and measurement techniques such as X-ray and neutron diffraction, small-angle and wide-angle X-ray scattering, free-electron laser imaging, cryo-electron microscopy, nuclear magnetic resonance, electron paramagnetic resonance, infrared and Raman spectroscopy, circular dichroism, Förster resonance energy transfer, atomic force microscopy and ion-mobility mass spectrometry. The process of deriving structural information from measured data is reviewed with an eye to non-experts and newcomers in the field using examples from the literature of the effect of the various choices and approximations involved in the process. A list of choices to be avoided is provided. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Experimental quantum control landscapes: Inherent monotonicity and artificial structure

    International Nuclear Information System (INIS)

    Roslund, Jonathan; Rabitz, Herschel

    2009-01-01

    Unconstrained searches over quantum control landscapes are theoretically predicted to generally exhibit trap-free monotonic behavior. This paper makes an explicit experimental demonstration of this intrinsic monotonicity for two controlled quantum systems: frequency unfiltered and filtered second-harmonic generation (SHG). For unfiltered SHG, the landscape is randomly sampled and interpolation of the data is found to be devoid of landscape traps up to the level of data noise. In the case of narrow-band-filtered SHG, trajectories are taken on the landscape to reveal a lack of traps. Although the filtered SHG landscape is trap free, it exhibits a rich local structure. A perturbation analysis around the top of these landscapes provides a basis to understand their topology. Despite the inherent trap-free nature of the landscapes, practical constraints placed on the controls can lead to the appearance of artificial structure arising from the resultant forced sampling of the landscape. This circumstance and the likely lack of knowledge about the detailed local landscape structure in most quantum control applications suggests that the a priori identification of globally successful (un)constrained curvilinear control variables may be a challenging task.

  1. Improving the physiological realism of experimental models

    NARCIS (Netherlands)

    Vinnakota, Kalyan C.; Cha, Chae Y.; Rorsman, Patrik; Balaban, Robert S.; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A.; Jeneson, Jeroen A. L.

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these

  2. Energy transfer in photosynthesis: experimental insights and quantitative models

    NARCIS (Netherlands)

    van Grondelle, R.; Novoderezhkin, V.

    2006-01-01

    We overview experimental and theoretical studies of energy transfer in the photosynthetic light-harvesting complexes LH1, LH2, and LHCII performed during the past decade since the discovery of high-resolution structure of these complexes. Experimental findings obtained with various spectroscopic

  3. The Dynamic Similitude Design Method of Thin Walled Structures and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Zhong Luo

    2016-01-01

    Full Text Available For the applicability of dynamic similitude models of thin walled structures, such as engine blades, turbine discs, and cylindrical shells, the dynamic similitude design of typical thin walled structures is investigated. The governing equation of typical thin walled structures is firstly unified, which guides to establishing dynamic scaling laws of typical thin walled structures. Based on the governing equation, geometrically complete scaling law of the typical thin walled structure is derived. In order to determine accurate distorted scaling laws of typical thin walled structures, three principles are proposed and theoretically proved by combining the sensitivity analysis and governing equation. Taking the thin walled annular plate as an example, geometrically complete and distorted scaling laws can be obtained based on the principles of determining dynamic scaling laws. Furthermore, the previous five orders’ accurate distorted scaling laws of thin walled annular plates are presented and numerically validated. Finally, the effectiveness of the similitude design method is validated by experimental annular plates.

  4. Track structure in biological models.

    Science.gov (United States)

    Curtis, S B

    1986-01-01

    High-energy heavy ions in the galactic cosmic radiation (HZE particles) may pose a special risk during long term manned space flights outside the sheltering confines of the earth's geomagnetic field. These particles are highly ionizing, and they and their nuclear secondaries can penetrate many centimeters of body tissue. The three dimensional patterns of ionizations they create as they lose energy are referred to as their track structure. Several models of biological action on mammalian cells attempt to treat track structure or related quantities in their formulation. The methods by which they do this are reviewed. The proximity function is introduced in connection with the theory of Dual Radiation Action (DRA). The ion-gamma kill (IGK) model introduces the radial energy-density distribution, which is a smooth function characterizing both the magnitude and extension of a charged particle track. The lethal, potentially lethal (LPL) model introduces lambda, the mean distance between relevant ion clusters or biochemical species along the track. Since very localized energy depositions (within approximately 10 nm) are emphasized, the proximity function as defined in the DRA model is not of utility in characterizing track structure in the LPL formulation.

  5. Practical application of stereological methods in experimental kidney animal models.

    Science.gov (United States)

    Fernández García, María Teresa; Núñez Martínez, Paula; García de la Fuente, Vanessa; Sánchez Pitiot, Marta; Muñiz Salgueiro, María Del Carmen; Perillán Méndez, Carmen; Argüelles Luis, Juan; Astudillo González, Aurora

    The kidneys are vital organs responsible for excretion, fluid and electrolyte balance and hormone production. The nephrons are the kidney's functional and structural units. The number, size and distribution of the nephron components contain relevant information on renal function. Stereology is a branch of morphometry that applies mathematical principles to obtain three-dimensional information from serial, parallel and equidistant two-dimensional microscopic sections. Because of the complexity of stereological studies and the lack of scientific literature on the subject, the aim of this paper is to clearly explain, through animal models, the basic concepts of stereology and how to calculate the main kidney stereological parameters that can be applied in future experimental studies. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  6. Optimization of experimental human leukemia models (review

    Directory of Open Access Journals (Sweden)

    D. D. Pankov

    2012-01-01

    Full Text Available Actual problem of assessing immunotherapy prospects including antigenpecific cell therapy using animal models was covered in this review.Describe the various groups of currently existing animal models and methods of their creating – from different immunodeficient mice to severalvariants of tumor cells engraftment in them. The review addresses the possibility of tumor stem cells studying using mouse models for the leukemia treatment with adoptive cell therapy including WT1. Also issues of human leukemia cells migration and proliferation in a mice withdifferent immunodeficiency degree are discussed. To assess the potential immunotherapy efficacy comparison of immunodeficient mouse model with clinical situation in oncology patients after chemotherapy is proposed.

  7. Ideal Experimental Rat Models for Liver Diseases

    OpenAIRE

    Lee, Sang Woo; Kim, Sung Hoon; Min, Seon Ok; Kim, Kyung Sik

    2011-01-01

    There are many limitations for conducting liver disease research in human beings due to the high cost and potential ethical issues. For this reason, conducting a study that is difficult to perform in humans using appropriate animal models, can be beneficial in ascertaining the pathological physiology, and in developing new treatment modalities. However, it is difficult to determine the appropriate animal model which is suitable for research purposes, since every patient has different and dive...

  8. Detection of damage in welded structure using experimental modal data

    Energy Technology Data Exchange (ETDEWEB)

    Abu Husain, N [Transportation Research Alliance, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Ouyang, H, E-mail: nurul@fkm.utm.my, E-mail: h.ouyang@liv.ac.uk [Department of Engineering, Harrison-Hughes Building, University of Liverpool, Brownlow Hill, Liverpool L69 3GH (United Kingdom)

    2011-07-19

    A typical automotive structure could contain thousands of spot weld joints that contribute significantly to the vehicle's structural stiffness and dynamic characteristics. However, some of these joints may be imperfect or even absent during the manufacturing process and they are also highly susceptible to damage due to operational and environmental conditions during the vehicle lifetime. Therefore, early detection and estimation of damage are important so necessary actions can be taken to avoid further problems. Changes in physical parameters due to existence of damage in a structure often leads to alteration of vibration modes; thus demonstrating the dependency between the vibration characteristics and the physical properties of structures. A sensitivity-based model updating method, performed using a combination of MATLAB and NASTRAN, has been selected for the purpose of this work. The updating procedure is regarded as parameter identification which aims to bring the numerical prediction to be as closely as possible to the measured natural frequencies and mode shapes data of the damaged structure in order to identify the damage parameters (characterised by the reductions in the Young's modulus of the weld patches to indicate the loss of material/stiffness at the damage region).

  9. Detection of damage in welded structure using experimental modal data

    International Nuclear Information System (INIS)

    Abu Husain, N; Ouyang, H

    2011-01-01

    A typical automotive structure could contain thousands of spot weld joints that contribute significantly to the vehicle's structural stiffness and dynamic characteristics. However, some of these joints may be imperfect or even absent during the manufacturing process and they are also highly susceptible to damage due to operational and environmental conditions during the vehicle lifetime. Therefore, early detection and estimation of damage are important so necessary actions can be taken to avoid further problems. Changes in physical parameters due to existence of damage in a structure often leads to alteration of vibration modes; thus demonstrating the dependency between the vibration characteristics and the physical properties of structures. A sensitivity-based model updating method, performed using a combination of MATLAB and NASTRAN, has been selected for the purpose of this work. The updating procedure is regarded as parameter identification which aims to bring the numerical prediction to be as closely as possible to the measured natural frequencies and mode shapes data of the damaged structure in order to identify the damage parameters (characterised by the reductions in the Young's modulus of the weld patches to indicate the loss of material/stiffness at the damage region).

  10. Experimental Verification of the Transient Model in an Enrichment Circuit

    International Nuclear Information System (INIS)

    Fernandino, Maria; Brasnarof, Daniel; Delmastro, Dario

    2003-01-01

    In the present work an experimental closed loop representing a single stage of an uranium gaseous diffusion enrichment cascade is described, loop that is used to experimentally validate an analytical model that describes the dynamics inside such a loop.The conditions established inside the experimental loop after a few working hours were reproduced by the analytical model, leaving the slower thermal phenomena taking place for future studies.Two kinds of perturbations were experimentally introduced: a change in the range of operation of one of the compressors and the addition of mass into the loop.Numerical and experimental results are compared and presented in this work. The analytical model proposed was verified against these two changes, with very good agreement in the time response and measured values.This analytical model allows us to determine the characteristic time response of the system

  11. An experimental comparison of modelling techniques for speaker ...

    Indian Academy of Sciences (India)

    Most of the existing modelling techniques for the speaker recognition task make an implicit assumption of sufficient data for speaker modelling and hence may lead to poor modelling under limited data condition. The present work gives an experimental evaluation of the modelling techniques like Crisp Vector Quantization ...

  12. An experimental comparison of modelling techniques for speaker ...

    Indian Academy of Sciences (India)

    Abstract. Most of the existing modelling techniques for the speaker recog- nition task make an implicit assumption of sufficient data for speaker modelling and hence may lead to poor modelling under limited data condition. The present work gives an experimental evaluation of the modelling techniques like Crisp.

  13. Numerical and Experimental Investigation of Stop-Bands in Finite and Infinite Periodic One-Dimensional Structures

    DEFF Research Database (Denmark)

    Domadiya, Parthkumar Gandalal; Manconi, Elisabetta; Vanali, Marcello

    2016-01-01

    structure. Numerical examples are presented, and results are discussed and validated experimentally. Very good agreement between the numerical and experimental models in terms of stop-bands is shown. In particular, the results show that the stop-bands obtained using a wave approach (applied to a single cell...

  14. Structure and modeling of turbulence

    International Nuclear Information System (INIS)

    Novikov, E.A.

    1995-01-01

    The open-quotes vortex stringsclose quotes scale l s ∼ LRe -3/10 (L-external scale, Re - Reynolds number) is suggested as a grid scale for the large-eddy simulation. Various aspects of the structure of turbulence and subgrid modeling are described in terms of conditional averaging, Markov processes with dependent increments and infinitely divisible distributions. The major request from the energy, naval, aerospace and environmental engineering communities to the theory of turbulence is to reduce the enormous number of degrees of freedom in turbulent flows to a level manageable by computer simulations. The vast majority of these degrees of freedom is in the small-scale motion. The study of the structure of turbulence provides a basis for subgrid-scale (SGS) models, which are necessary for the large-eddy simulations (LES)

  15. Experimental researches on roadbed structural reinforcement with geogrid on automobile road

    Directory of Open Access Journals (Sweden)

    Kudryavtsev Sergey

    2017-01-01

    Full Text Available The paper considers experimental and theoretical researches on layers reduction in the pavement base strucure using geogrids on the Amur automobile road (Chita – Khabarovsk. The calculations on transverse elasticity limits are carried out, and some structural designs of a regular pavement and a new one with reduced base layers are offered. A geotechnical modelling with the finite element methods in the software package FEM-models is carried out to evaluate a rational design. The experimental researches on determining the pavement elasticity modulus by the stamp proves both designs being equal in terms of their deformability. The experimental researches on determining the pavement base stress strain behavior caused by the operational loads show a reduction of stresses under the geogrid. The survey of deformations in the embankment and the pavement are presented.

  16. Measuring and modelling the structure of chocolate

    Science.gov (United States)

    Le Révérend, Benjamin J. D.; Fryer, Peter J.; Smart, Ian; Bakalis, Serafim

    2015-01-01

    The cocoa butter present in chocolate exists as six different polymorphs. To achieve the desired crystal form (βV), traditional chocolate manufacturers use relatively slow cooling (chocolate products during processing as well as the crystal structure of cocoa butter throughout the process. A set of ordinary differential equations describes the kinetics of fat crystallisation. The parameters were obtained by fitting the model to a set of DSC curves. The heat transfer equations were coupled to the kinetic model and solved using commercially available CFD software. A method using single crystal XRD was developed using a novel subtraction method to quantify the cocoa butter structure in chocolate directly and results were compared to the ones predicted from the model. The model was proven to predict phase change temperature during processing accurately (±1°C). Furthermore, it was possible to correctly predict phase changes and polymorphous transitions. The good agreement between the model and experimental data on the model geometry allows a better design and control of industrial processes.

  17. Ideal Experimental Rat Models for Liver Diseases.

    Science.gov (United States)

    Lee, Sang Woo; Kim, Sung Hoon; Min, Seon Ok; Kim, Kyung Sik

    2011-05-01

    There are many limitations for conducting liver disease research in human beings due to the high cost and potential ethical issues. For this reason, conducting a study that is difficult to perform in humans using appropriate animal models, can be beneficial in ascertaining the pathological physiology, and in developing new treatment modalities. However, it is difficult to determine the appropriate animal model which is suitable for research purposes, since every patient has different and diverse clinical symptoms, adverse reactions, and complications due to the pathological physiology. Also, it is not easy to reproduce identically various clinical situations in animal models. Recently, the Guide for the Care and Use of Laboratory Animals has tightened up the regulations, and therefore it is advisable to select the appropriate animals and decide upon the appropriate quantities through scientific and systemic considerations before conducting animal testing. Therefore, in this review article the authors examined various white rat animal testing models and determined the appropriate usable rat model, and the pros and cons of its application in liver disease research. The authors believe that this review will be beneficial in selecting proper laboratory animals for research purposes.

  18. Structural Agricultural Land Use Modelling

    OpenAIRE

    Fezzi, Carlo; Bateman, Ian J.

    2009-01-01

    This paper develops a structural econometric model of agricultural land use and production based on the joint multi-output technology representation introduced by Chambers and Just (1989). Starting from a flexible specification of the farm profit function we derive land use allocation, input applications, crops yield and livestock number equations in a joint and theoretically consistent framework. We present an empirical application using fine-scale spatial data covering the entirety of Engla...

  19. A DIDATIC EXPERIENCE IN BIOCHEMISTRY LABWORKS: THEORETICALVERSUS EXPERIMENTAL MODEL

    Directory of Open Access Journals (Sweden)

    B.C Rossi-Rodrigues

    2008-05-01

    Full Text Available Biochemistry labworks are fundamental to both the instrumentation and  for  the  establishment of important concepts. The labworks of Basic  Biochemistry  (BB280 for Biology students at UNICAMP have gone through several  improvements. The labworks are  now  structured  from simple  activities to more complex ones, and aimed  to  the student’s  autonomy  development  in the experiments planning and execution  over  the teaching  semester. The first practical activity is on buffer systems, and   it is based  on  the confrontation of a theoretical model with the  lab experiments results.  First of all, the students  simulate  a Titration  in  a computational environment, where students lay a theoretical model from their knowledge. In the theoretical model the buffer parameters are set according to the teacher instructions, and the experiment conditions are also set and tested.  The simulation results are used for planning  the experiment and to compare with the experimental ones.  After having the simulations concluded and having the experiment planned the students  perform  the  in lab  Titration with the parameters established in the simulation. The results obtained by students are presented in a report. We analyzed the reports from 76 BB280’s students in 2007(night class and day class. The students identified as the main causes of the discrepancy between theoretical and experimental data: 1 experimental errors, related to the lack of technical skill 2 limitation of equipment used 3 unexpected behavior of the substances  used. In addition to the theoretical content related to  labwork, the confrontation between the  simulation and experimentation provided the students with ability  to identify the main aspects of which can influence the quality of the data obtained.

  20. Blast Testing and Modelling of Composite Structures

    DEFF Research Database (Denmark)

    Giversen, Søren

    The motivation for this work is based on a desire for finding light weight alternatives to high strength steel as the material to use for armouring in military vehicles. With the use of high strength steel, an increase in the level of armouring has a significant impact on the vehicle weight......-up proved functional and provided consistent data of the panel response. The tests reviled that the sandwich panels did not provide a decrease in panel deflection compared with the monolithic laminates, which was expected due to their higher flexural rigidity. This was found to be because membrane effects...... a pressure distribution on a selected surfaces and has been based on experimental pressure measurement data, and (ii) with a designed 3 step numerical load model, where the blast pressure and FSI (Fluid Structure Interaction) between the pressure wave and modelled panel is modelled numerically. The tested...

  1. Scaled Experimental Modeling of VHTR Plenum Flows

    International Nuclear Information System (INIS)

    ICONE, 15

    2007-01-01

    The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. Various scaled heated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification (''thermal striping'') in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the density effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, Reynolds number scaling distortions will occur at matching Richardson numbers due primarily to the necessity of using a reduced number of channels connected to the plenum than in the prototype (which has approximately 11,000 core channels connected to the upper plenum) in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums

  2. Scaled experimental modeling of VHTR plenum flows

    International Nuclear Information System (INIS)

    McCreery, Glenn E.; Condie, Keith G.; Schultz, Richard R.

    2007-01-01

    The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. Various scaled heated and unheated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification ('thermal striping') in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the buoyancy effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, scaling distortions will occur due primarily to the necessity of using a reduced number of channels connected to the upper plenum than in the prototype in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums. (author)

  3. Scaled Experimental Modeling of VHTR Plenum Flows

    Energy Technology Data Exchange (ETDEWEB)

    ICONE 15

    2007-04-01

    Abstract The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. Various scaled heated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification (“thermal striping”) in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the density effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, Reynolds number scaling distortions will occur at matching Richardson numbers due primarily to the necessity of using a reduced number of channels connected to the plenum than in the prototype (which has approximately 11,000 core channels connected to the upper plenum) in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums.

  4. Efficient experimental designs for sigmoidal growth models

    OpenAIRE

    Dette, Holger; Pepelyshev, Andrey

    2005-01-01

    For the Weibull- and Richards-regression model robust designs are determined by maximizing a minimum of D- or D1-efficiencies, taken over a certain range of the non-linear parameters. It is demonstrated that the derived designs yield a satisfactory solution of the optimal design problem for this type of model in the sense that these designs are efficient and robust with respect to misspecification of the unknown parameters. Moreover, the designs can also be used for testing the postulated for...

  5. Influence of Mebivid on the Structural and Functional State of Bone Tissue in Experimental Nutritional Osteoporosis

    Directory of Open Access Journals (Sweden)

    A.T. Brusko

    2015-10-01

    Full Text Available To determine the impact of domestic combined preparation mebivid containing vitamin D3 and bisphosphonate on the normalization of the structural and functional state of epiphyseal cartilage and bone tissue, we have conducted an experimental study on 30 Wistar rats weighing 90 ± 5 g. We used nutritional model of osteoporosis. Histomorphologic and osteometric studies were carried out, bone ash content was determined. The study found that mebivid effectively influences the normalization of disorders of the structural and functional state of epiphyseal cartilage and bone tissue in the nutritional osteoporosis in rats. Experimental studies demonstrate the feasibility of using a combined drug mebivid in the treatment of orthopedic diseases associated with impaired longitudinal growth, increase in thickness and structural and functional state of bone tissue.

  6. Numerical and experimental investigation on structure-borne sound transmission in multilayered concrete structures

    Science.gov (United States)

    Asakura, T.; Toyoda, M.; Miyajima, T.

    2018-01-01

    Environmental vibrations in cities are transmitted to buildings and propagate through the buildings via complex paths composed of the structural elements in the building, such as concrete slabs, beams, and columns. In this study, the transmission characteristics of such structure-borne sound in building structures composed of concrete were experimentally and numerically investigated. The vibration and radiated sound characteristics of a five-storey concrete structure obtained experimentally through an excitation test using the hammering method and numerically through wave-based numerical calculations are presented and compared. In this study, the finite-difference time-domain (FDTD) method, which treats the target structure as a composition of two-dimensional plate and one-dimensional beam elements to enable a low-cost calculation, is applied as a wave-based scheme. The propagation characteristics of the vibration and sound within the same floor and across different floors were investigated by considering various combinations of receiver and source points, and the structure-borne sound transmission characteristics of a concrete structure with frame elements are discussed.

  7. Experimental Measurement, Analysis and Modelling of Dependency ...

    African Journals Online (AJOL)

    We propose a direct method of measurement of the total emissivity of opaque samples on a range of temperature around the ambient one. The method rests on the modulation of the temperature of the sample and the infra-red signal processing resulting from the surface of the sample we model the total emissivity obtained ...

  8. Isothermal coarse mixing: experimental and CFD modelling

    International Nuclear Information System (INIS)

    Gilbertson, M.A.; Kenning, D.B.R.; Hall, R.W.

    1992-01-01

    A plane, two-dimensional flow apparatus has been built which uses a jet of solid 6mm diameter balls to model a jet of molten drops falling into a tank of water to study premixing prior to a vapour explosion. Preliminary experiments with unheated stainless steel balls are here compared with computational fluid dynamics (CFD) calculations by the code CHYMES. (6 figures) (Author)

  9. New experimental model of multiple myeloma.

    Science.gov (United States)

    Telegin, G B; Kalinina, A R; Ponomarenko, N A; Ovsepyan, A A; Smirnov, S V; Tsybenko, V V; Homeriki, S G

    2001-06-01

    NSO/1 (P3x63Ay 8Ut) and SP20 myeloma cells were inoculated to BALB/c OlaHsd mice. NSO/1 cells allowed adequate stage-by-stage monitoring of tumor development. The adequacy of this model was confirmed in experiments with conventional cytostatics: prospidium and cytarabine caused necrosis of tumor cells and reduced animal mortality.

  10. Track structure model of cell damage in space flight

    Science.gov (United States)

    Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Shinn, Judy L.; Ngo, Duc M.

    1992-01-01

    The phenomenological track-structure model of cell damage is discussed. A description of the application of the track-structure model with the NASA Langley transport code for laboratory and space radiation is given. Comparisons to experimental results for cell survival during exposure to monoenergetic, heavy-ion beams are made. The model is also applied to predict cell damage rates and relative biological effectiveness for deep-space exposures.

  11. Simulation and experimentation of PSCAR chemistry for complex structures

    Science.gov (United States)

    Carcasi, Michael; Nagahara, Seiji; Shiraishi, Gosuke; Iseki, Tomohiro; Minekawa, Yukie; Yoshihara, Kosuke; Nakagawa, Hisashi; Naruoka, Takehiko; Nagai, Tomoki; Oshima, Akihiro; Tagawa, Seiichi

    2017-03-01

    Extreme ultraviolet lithography (EUVL, λ = 13.5 nm) continues to be one of the most important candidates for future technology nodes. For the insertion of EUV lithography into device mass production, higher sensitivity of EUV resists is helpful for better cost of ownership of the EUV tool and light source. However, obtaining low sensitivity (S), high resolution (R), and low line edge roughness (L) simultaneously is very difficult. Many previous experiments by lithographers proved the existence of this "RLS trade-off"1-2. This paper furthers the work related to Photosensitized Chemically Amplified ResistTM (PSCAR)TM**, a chemistry which is trying to break the "RLS tradeoff" relationship. This chemistry was introduced as a new chemically amplified lithographic concept and is accomplished in an in-line track tool with secondary exposure module connected to EUV exposure tool. PSCAR is a modified CAR which contains a photosensitizer precursor (PP) in addition to other standard CAR components such as a protected polymer, a photo acid generator (PAG) and a quencher. In the PSCAR process, an improved chemical gradient can be realized by dual acid quenching steps with the help of increased quencher concentration. The addition of the PP, as well as other material optimization, offers more degrees of freedom for getting high sensitivity and low LER, but also makes the system more complicated. Thus coupling simulation and experimentation is the most rational approach to optimizing the overall process and for understanding complicated 2-D structures. In this paper, we will provide additional background into the simulation of PSCAR chemistry, explore the effects of PSCAR chemistry on chemical contrast of complex structures (e.g. T structures, slot contacts, I/D bias for L/S), and explore the sensitivity enhancement levels capable while improving or maintaining lithographic performance. Finally, we will explore modifications of PSCAR chemistry on performance.

  12. Experimental Validation of a Permeability Model for Enrichment Membranes

    International Nuclear Information System (INIS)

    Orellano, Pablo; Brasnarof, Daniel; Florido Pablo

    2003-01-01

    An experimental loop with a real scale diffuser, in a single enrichment-stage configuration, was operated with air at different process conditions, in order to characterize the membrane permeability.Using these experimental data, an analytical geometric-and-morphologic-based model was validated.It is conclude that a new set of independent measurements, i.e. enrichment, is necessary in order to fully characterize diffusers, because of its internal parameters are not univocally determinated with permeability experimental data only

  13. New experimental model for training in videosurgery Novo modelo experimental para treinamento em videocirurgia

    Directory of Open Access Journals (Sweden)

    Danilo Malta Batista

    2012-10-01

    Full Text Available PURPOSE: To develop a new experimental model of lower cost for training in videosurgery. METHODS: This project was performed at the Nucleus of Experimental Surgery of the Bahiana School of Medicine and Public Health, based on previous models described in the literature and under the supervision of the full professor of Operative Technique and Experimental Surgery II. It was made a model cube-shaped, made of wood, with holes distributed in various locations, rubber stoppers for the holes and lined externally with carpet, and internally with laminate. RESULTS: The new experimental model is of low cost and reproduces quite faithfully several videosurgical procedures. CONCLUSION: Medical schools interested in the subject may adopt the new model for training in videosurgery without the need of high costs for making and using these models.OBJETIVO: Desenvolver um novo modelo experimental de baixo custo para treinamento em videocirurgia MÉTODOS: Este projeto foi conduzido no Núcleo de Cirurgia Experimental da Escola Bahiana de Medicina e Saúde Pública, baseado em modelos prévios descritos na literatura e sob a supervisão do professor titular de Técnica Operatória e Cirurgia Experimental II. Foi feito um modelo em formato de cubo, de madeira, com furos distribuídos em vários locais, tampas de borracha para os orifícios e forrado externamente com carpete e internamente com laminado. RESULTADOS: O novo modelo experimental desenvolvido é de baixo custo e reproduz de forma bastante fiel diversos procedimentos videocirúrgicos. CONCLUSÃO: Faculdades médicas interessadas no tema poderão adotar o novo modelo para o treinamento em videocirurgia sem que sejam necessários gastos elevados para a confecção e o uso desses modelos.

  14. Structural fire resistance experimental research priority needs of U.S. industry

    CERN Document Server

    Almand, Kathleen H

    2012-01-01

    Structural Fire Resistance Experimental Research – Priority Needs of U.S. Industry provides a synthesis of stakeholder input to a prioritized agenda for research at the National Fire Research Laboratory (NFRL) at the National Institute of Standards and Technology (NIST) designed to accelerate the implementation of performance-based fire engineering for structures. The NFRL presents a broad range of unanswered questions regarding the performance of real structures in fire conditions, and informs performance-based design methods and standards in this field. The authors conducted a comprehensive literature review of large-scale structural fire testing and compiled research needs from a variety of sources. The book addresses major issues of broad concern in the fire community, such as real fire exposure and structural response, composite floor system performance, enhancing modeling performance, and understanding the embedded safety features in design methods. It concludes with a prioritized set of research reco...

  15. Structural modeling of HTS tapes and cables

    Science.gov (United States)

    Allen, N. C.; Chiesa, L.; Takayasu, M.

    2016-12-01

    Structural finite element analysis (FEA) has been used as an insightful tool to investigate the electromechanical behavior of HTS REBCO tapes and twisted stacked-tape cables under tension, torsion, bending and combined loads. A novel technique was developed for modeling the layered composite structure of the 2G tapes with structural solid-shell elements in ANSYS®. The FEA models produced detailed strain information for the REBCO superconducting layer which was then paired with an analytical model to predict the critical current performance of the 2G HTS tapes under various loads. Two commercially available HTS tapes (SuperPower and SuNAM) under tension, torsion and combined tension-torsion were first analyzed with FEA and compared with available experimental results at 77 K. A sharp critical current degradation was experienced at the yield strength of the tapes under tension and below a 100 mm twist-pitch under torsion. Combined tension-torsion loads had a more gradual degradation of critical current for twist-pitches of 115 mm or shorter but had a negligible difference compared to pure tension for longer twist-pitches. Using the structural solid-shell technique for modeling 2G tapes in ANSYS®, an FEA methodology for simulating full scale three-dimensional HTS stacked-tape cables under pure bending was created. A model of a Twisted-Stacked Tape Cable (TSTC), a configuration first proposed at MIT, was initially developed and then adapted to the slotted-core HTS Cable-In-Conduit Conductor produced by the ENEA laboratory in Italy. The numerical axial strain of the HTS REBCO tapes within the cables as calculated by FEA were found to agree with an analytical model for two cases: perfect-slip (frictionless) and no-slip (bonded). The ENEA CICC model was also compared with recent experimental critical current data at 77 K and was found to match best using a low friction coefficient of 0.02 indicating that the tapes within the cable freely slide with respect to each other

  16. A systematic multiscale modeling and experimental approach to protect grain boundaries in magnesium alloys from corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Horstemeyer, Mark R. [Mississippi State Univ., Mississippi State, MS (United States); Chaudhuri, Santanu [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2015-09-30

    A multiscale modeling Internal State Variable (ISV) constitutive model was developed that captures the fundamental structure-property relationships. The macroscale ISV model used lower length scale simulations (Butler-Volmer and Electronics Structures results) in order to inform the ISVs at the macroscale. The chemomechanical ISV model was calibrated and validated from experiments with magnesium (Mg) alloys that were investigated under corrosive environments coupled with experimental electrochemical studies. Because the ISV chemomechanical model is physically based, it can be used for other material systems to predict corrosion behavior. As such, others can use the chemomechanical model for analyzing corrosion effects on their designs.

  17. Experimentally testing the standard cosmological model

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))

    1990-11-01

    The standard model of cosmology, the big bang, is now being tested and confirmed to remarkable accuracy. Recent high precision measurements relate to the microwave background; and big bang nucleosynthesis. This paper focuses on the latter since that relates more directly to high energy experiments. In particular, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard cosmology scenario. Discussion is presented on the improved light element observational data as well as the improved neutron lifetime data. alternate nucleosynthesis scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, {Omega}{sub b}, remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the standard model conclusion that {Omega}{sub b} {approximately} 0.06. This latter point is the deriving force behind the need for non-baryonic dark matter (assuming {Omega}{sub total} = 1) and the need for dark baryonic matter, since {Omega}{sub visible} < {Omega}{sub b}. Recent accelerator constraints on non-baryonic matter are discussed, showing that any massive cold dark matter candidate must now have a mass M{sub x} {approx gt} 20 GeV and an interaction weaker than the Z{sup 0} coupling to a neutrino. It is also noted that recent hints regarding the solar neutrino experiments coupled with the see-saw model for {nu}-masses may imply that the {nu}{sub {tau}} is a good hot dark matter candidate. 73 refs., 5 figs.

  18. Experimental modeling of a deoiling hydrocyclone system

    DEFF Research Database (Denmark)

    Bram, Mads Valentin; Hassan, Abdiladif Ahmed; Hansen, Dennis Severin

    2015-01-01

    Hydrocyclones used in offshore oil & gas industries utilizes pressure difference ratio (PDR) control to maintain efficient oil and water separation. This separation will reduce the concentration of oil in the effluent water to fulfill the environmental safety limits of low oil concentrations....... This limitation causes the optimization of the separation process to be an important research. As oscillating flow affects the hydrocyclones performance, it is important to identify the dynamic model of the hydrocyclones to possibly optimize and improve the current PDR control solution. An in-house developed...

  19. Experimental modeling methods in Industrial Engineering

    Directory of Open Access Journals (Sweden)

    Peter Trebuňa

    2009-03-01

    Full Text Available Dynamic approaches to a management system of the present industrial practice, forcing businesses to address management issues in-house continuous improvement of production and non-production processes. Experience has repeatedly demonstrated the need for a system approach not only in analysis but also in the planning and actual implementation of these processes. Therefore, the contribution is focused on the description of the modeling in industrial practice by a system approach, in order to avoid erroneous application of the decision to the implementation phase, and thus prevent any longer applying methods "attempt - fallacy".

  20. CS model coil experimental log book

    International Nuclear Information System (INIS)

    Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi; Tsuji, Hiroshi

    2001-02-01

    Charging test of the ITER CS Model Coil which is the world's largest superconducting pulse coil and the CS Insert Coil had started at April 11, 2000 and had completed at August 18, 2000. In the campaign, total shot numbers were 356 and the size of the data file in the DAS (Data Acquisition System) was over 20 GB. This report is a database that consists of the log list and the log sheets of every shot. One can access the database, make a search, and browse results via Internet (http://1ogwww.naka.jaeri.go.jp). The database will be useful to quick search to choose necessary shots. (author)

  1. Experimental determination of neutron capture cross sections of fast reactor structure materials integrated in intermediate energy spectra. Vol. 2: description of experimental structure

    International Nuclear Information System (INIS)

    Tassan, S.

    1978-01-01

    A selection of technical documents is given concerning the experimental determination of the neutron capture cross-sections of fast reactor structural materials (Fe, Cr, Ni...) integrated over the intermediate energy spectra. The experimental structure project and modifications of the reactor RB2 for this experiment, together with criticality and safety calculations, are presented

  2. Computational modeling of RNA 3D structures and interactions.

    Science.gov (United States)

    Dawson, Wayne K; Bujnicki, Janusz M

    2016-04-01

    RNA molecules have key functions in cellular processes beyond being carriers of protein-coding information. These functions are often dependent on the ability to form complex three-dimensional (3D) structures. However, experimental determination of RNA 3D structures is difficult, which has prompted the development of computational methods for structure prediction from sequence. Recent progress in 3D structure modeling of RNA and emerging approaches for predicting RNA interactions with ions, ligands and proteins have been stimulated by successes in protein 3D structure modeling. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. A study on identification of nonlinear structure by experimental modal analysis

    International Nuclear Information System (INIS)

    Sone, Akira; Suzuki, Kohei; Nakamura, Hajime.

    1990-01-01

    In this paper, identification techniques based on the experimental modal analysis for the equivalent modal parameters of nonlinear structures are examined from a practical viewpoint. First, using a simple cantilever model with gap or friction at the supported end, the gain characteristics of transfer function are evaluated through the sinusoidal sweep test and random wave test. Second, the equivalent modal parameters such as natural frequency and damping ratio are estimated by two types of identification techniques: ARMA (autoregressive/moving average) model fitting and curve fitting with iterative calculations. From the comparison of the response of the model obtained by the random excitation test and numerical calculation using the equivalent modal parameters, it has been clarified that the ARMA model fitting can be applied to linearized modal parameter identification for nonlinear structures. (author)

  4. Multiphysics modelling and experimental validation of high concentration photovoltaic modules

    International Nuclear Information System (INIS)

    Theristis, Marios; Fernández, Eduardo F.; Sumner, Mike; O'Donovan, Tadhg S.

    2017-01-01

    Highlights: • A multiphysics modelling approach for concentrating photovoltaics was developed. • An experimental campaign was conducted to validate the models. • The experimental results were in good agreement with the models. • The multiphysics modelling allows the concentrator’s optimisation. - Abstract: High concentration photovoltaics, equipped with high efficiency multijunction solar cells, have great potential in achieving cost-effective and clean electricity generation at utility scale. Such systems are more complex compared to conventional photovoltaics because of the multiphysics effect that is present. Modelling the power output of such systems is therefore crucial for their further market penetration. Following this line, a multiphysics modelling procedure for high concentration photovoltaics is presented in this work. It combines an open source spectral model, a single diode electrical model and a three-dimensional finite element thermal model. In order to validate the models and the multiphysics modelling procedure against actual data, an outdoor experimental campaign was conducted in Albuquerque, New Mexico using a high concentration photovoltaic monomodule that is thoroughly described in terms of its geometry and materials. The experimental results were in good agreement (within 2.7%) with the predicted maximum power point. This multiphysics approach is relatively more complex when compared to empirical models, but besides the overall performance prediction it can also provide better understanding of the physics involved in the conversion of solar irradiance into electricity. It can therefore be used for the design and optimisation of high concentration photovoltaic modules.

  5. Mathematical Models and the Experimental Analysis of Behavior

    Science.gov (United States)

    Mazur, James E.

    2006-01-01

    The use of mathematical models in the experimental analysis of behavior has increased over the years, and they offer several advantages. Mathematical models require theorists to be precise and unambiguous, often allowing comparisons of competing theories that sound similar when stated in words. Sometimes different mathematical models may make…

  6. Experimental Tests of the Algebraic Cluster Model

    Science.gov (United States)

    Gai, Moshe

    2018-02-01

    The Algebraic Cluster Model (ACM) of Bijker and Iachello that was proposed already in 2000 has been recently applied to 12C and 16O with much success. We review the current status in 12C with the outstanding observation of the ground state rotational band composed of the spin-parity states of: 0+, 2+, 3-, 4± and 5-. The observation of the 4± parity doublet is a characteristic of (tri-atomic) molecular configuration where the three alpha- particles are arranged in an equilateral triangular configuration of a symmetric spinning top. We discuss future measurement with electron scattering, 12C(e,e’) to test the predicted B(Eλ) of the ACM.

  7. CS model coil experimental log book

    Energy Technology Data Exchange (ETDEWEB)

    Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi; Tsuji, Hiroshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-02-01

    Charging test of the ITER CS Model Coil which is the world's largest superconducting pulse coil and the CS Insert Coil had started at April 11, 2000 and had completed at August 18, 2000. In the campaign, total shot numbers were 356 and the size of the data file in the DAS (Data Acquisition System) was over 20 GB. This report is a database that consists of the log list and the log sheets of every shot. One can access the database, make a search, and browse results via Internet (http://1ogwww.naka.jaeri.go.jp). The database will be useful to quick search to choose necessary shots. (author)

  8. Microplasticity of MMC. Experimental results and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Maire, E. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Lormand, G. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Gobin, P.F. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Fougeres, R. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France))

    1993-11-01

    The microplastic behavior of several MMC is investigated by means of tension and compression tests. This behavior is assymetric : the proportional limit is higher in tension than in compression but the work hardening rate is higher in compression. These differences are analysed in terms of maxium of the Tresca's shear stress at the interface (proportional limit) and of the emission of dislocation loops during the cooling (work hardening rate). On another hand, a model is proposed to calculate the value of the yield stress, describing the composite as a material composed of three phases : inclusion, unaffected matrix and matrix surrounding the inclusion having a gradient in the density of the thermally induced dilocations. (orig.).

  9. Generalized latent variable modeling multilevel, longitudinal, and structural equation models

    CERN Document Server

    Skrondal, Anders; Rabe-Hesketh, Sophia

    2004-01-01

    This book unifies and extends latent variable models, including multilevel or generalized linear mixed models, longitudinal or panel models, item response or factor models, latent class or finite mixture models, and structural equation models.

  10. Visualization of RNA structure models within the Integrative Genomics Viewer.

    Science.gov (United States)

    Busan, Steven; Weeks, Kevin M

    2017-07-01

    Analyses of the interrelationships between RNA structure and function are increasingly important components of genomic studies. The SHAPE-MaP strategy enables accurate RNA structure probing and realistic structure modeling of kilobase-length noncoding RNAs and mRNAs. Existing tools for visualizing RNA structure models are not suitable for efficient analysis of long, structurally heterogeneous RNAs. In addition, structure models are often advantageously interpreted in the context of other experimental data and gene annotation information, for which few tools currently exist. We have developed a module within the widely used and well supported open-source Integrative Genomics Viewer (IGV) that allows visualization of SHAPE and other chemical probing data, including raw reactivities, data-driven structural entropies, and data-constrained base-pair secondary structure models, in context with linear genomic data tracks. We illustrate the usefulness of visualizing RNA structure in the IGV by exploring structure models for a large viral RNA genome, comparing bacterial mRNA structure in cells with its structure under cell- and protein-free conditions, and comparing a noncoding RNA structure modeled using SHAPE data with a base-pairing model inferred through sequence covariation analysis. © 2017 Busan and Weeks; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  11. Reinforced concrete structures loaded by snow avalanches : numerical and experimental approaches.

    Science.gov (United States)

    Ousset, I.; Bertrand, D.; Brun, M.; Limam, A.; Naaim, M.

    2012-04-01

    Today, due to the extension of occupied areas in mountainous regions, new strategies for risk mitigation have to be developed. In the framework of risk analysis, these latter have to take into account not only the natural hazard description but also the physical vulnerability of the exposed structures. From a civil engineering point of view, the dynamic behavior of column or portico was widely investigated especially in the case of reinforced concrete and steel. However, it is not the case of reinforced concrete walls for which only the in-plan dynamic behavior (shear behavior) has been studied in detail in the field of earthquake engineering. Therefore, the aim of this project is to study the behavior of reinforced concrete civil engineering structures submitted to out-of-plan dynamic loadings coming from snow avalanche interaction. Numerical simulations in 2D or 3D by the finite element method (FEM) are presented. The approach allows solving mechanical problems in dynamic condition involving none linearities (especially none linear materials). Thus, the structure mechanical response can be explored in controlled conditions. First, a reinforced concrete wall with a L-like shape is considered. The structure is supposed to represent a French defense structure dedicated to protect people against snow avalanches. Experimental pushover tests have been performed on a physical model. The experimental tests consisted to apply a uniform distribution of pressure until the total collapse of the wall. A 2D numerical model has been developed to simulate the mechanical response of the structure under quasi-static loading. Numerical simulations have been compared to experimental datas and results gave a better understanding of the failure mode of the wall. Moreover, the influence of several parameters (geometry and the mechanical properties) is also presented. Secondly, punching shear experimental tests have also been carried out. Reinforced concrete slabs simply supported have

  12. Experimental tests of the standard model

    International Nuclear Information System (INIS)

    Nodulman, L.

    1998-01-01

    The title implies an impossibly broad field, as the Standard Model includes the fermion matter states, as well as the forces and fields of SU(3) x SU(2) x U(1). For practical purposes, I will confine myself to electroweak unification, as discussed in the lectures of M. Herrero. Quarks and mixing were discussed in the lectures of R. Aleksan, and leptons and mixing were discussed in the lectures of K. Nakamura. I will essentially assume universality, that is flavor independence, rather than discussing tests of it. I will not pursue tests of QED beyond noting the consistency and precision of measurements of α EM in various processes including the Lamb shift, the anomalous magnetic moment (g-2) of the electron, and the quantum Hall effect. The fantastic precision and agreement of these predictions and measurements is something that convinces people that there may be something to this science enterprise. Also impressive is the success of the ''Universal Fermi Interaction'' description of beta decay processes, or in more modern parlance, weak charged current interactions. With one coupling constant G F , most precisely determined in muon decay, a huge number of nuclear instabilities are described. The slightly slow rate for neutron beta decay was one of the initial pieces of evidence for Cabbibo mixing, now generalized so that all charged current decays of any flavor are covered

  13. Experimental tests of the standard model.

    Energy Technology Data Exchange (ETDEWEB)

    Nodulman, L.

    1998-11-11

    The title implies an impossibly broad field, as the Standard Model includes the fermion matter states, as well as the forces and fields of SU(3) x SU(2) x U(1). For practical purposes, I will confine myself to electroweak unification, as discussed in the lectures of M. Herrero. Quarks and mixing were discussed in the lectures of R. Aleksan, and leptons and mixing were discussed in the lectures of K. Nakamura. I will essentially assume universality, that is flavor independence, rather than discussing tests of it. I will not pursue tests of QED beyond noting the consistency and precision of measurements of {alpha}{sub EM} in various processes including the Lamb shift, the anomalous magnetic moment (g-2) of the electron, and the quantum Hall effect. The fantastic precision and agreement of these predictions and measurements is something that convinces people that there may be something to this science enterprise. Also impressive is the success of the ''Universal Fermi Interaction'' description of beta decay processes, or in more modern parlance, weak charged current interactions. With one coupling constant G{sub F}, most precisely determined in muon decay, a huge number of nuclear instabilities are described. The slightly slow rate for neutron beta decay was one of the initial pieces of evidence for Cabbibo mixing, now generalized so that all charged current decays of any flavor are covered.

  14. Kinematic models of extensional structures

    International Nuclear Information System (INIS)

    Groshong, R.H. Jr.

    1990-01-01

    This paper discusses kinematic models that can relate faults of different types and different positions within a single dynamic system and thereby offer the potential to explain the disparate seismic activity characteristic of extensional terrains. The major styles are full grabens, half grabens, domino blocks, and glide-block systems. Half grabens, the most likely models for Basin and Range structure, are formed above a master fault of decreasing dip with depth and a hangingwall that deforms as it passes over the curved fault. Second-order normal faults, typically domino style, accommodate the required hangingwall deformation. According to the author low-angle detachment faults are consistent with the evidence of seismicity only on high-angle faults if the hangingwall of the detachment is broken by multiple half-graben systems

  15. Impact of model defect and experimental uncertainties on evaluated output

    International Nuclear Information System (INIS)

    Neudecker, D.; Capote, R.; Leeb, H.

    2013-01-01

    One of the current major problems in nuclear data evaluation is the unreasonably small evaluated uncertainties often obtained. These small uncertainties are partly attributed to missing correlations of experimental uncertainties as well as to deficiencies of the model employed for the prior information. In this article, both uncertainty sources are included in an evaluation of 55 Mn cross-sections for incident neutrons. Their impact on the evaluated output is studied using a prior obtained by the Full Bayesian Evaluation Technique and a prior obtained by the nuclear model program EMPIRE. It is shown analytically and by means of an evaluation that unreasonably small evaluated uncertainties can be obtained not only if correlated systematic uncertainties of the experiment are neglected but also if prior uncertainties are smaller or about the same magnitude as the experimental ones. Furthermore, it is shown that including model defect uncertainties in the evaluation of 55 Mn leads to larger evaluated uncertainties for channels where the model is deficient. It is concluded that including correlated experimental uncertainties is equally important as model defect uncertainties, if the model calculations deviate significantly from the measurements. -- Highlights: • We study possible causes of unreasonably small evaluated nuclear data uncertainties. • Two different formulations of model defect uncertainties are presented and compared. • Smaller prior than experimental uncertainties cause too small evaluated ones. • Neglected correlations of experimental uncertainties cause too small evaluated ones. • Including model defect uncertainties in the prior improves the evaluated output

  16. Powered Paraglider Longitudinal Dynamic Modeling and Experimentation

    Science.gov (United States)

    Gibson, Colin P.

    Paragliders and similar controllable decelerators provide the benefits of a compact packable parachute with the improved glide performance and steering of a conventional wing, making them ideally suited for precise high offset payload recovery and airdrop missions. This advantage over uncontrollable conventional parachutes sparked interest from Oklahoma State University for implementation into its Atmospheric and Space Threshold Research Oklahoma (ASTRO) program, where payloads often descend into wooded areas. However, due to complications while building a powered paraglider to evaluate the concept, more research into its design parameters was deemed necessary. Focus shifted to an investigation of the effects of these parameters on the flight behavior of a powered system. A longitudinal dynamic model, based on Lagrange's equation for adaptability when adding free-hanging masses, was developed to evaluate trim conditions and analyze system response. With the simulation, the effects of rigging angle, fuselage weight, center of gravity (cg), and apparent mass were calculated through step thrust input cases. Test flights evaluated the behavior of the paraglider, and the design was revised based on observations and analysis. Rigging angle sets the power-off glide slope as well as thrust capacity and input response damping. At more negative angles the glide slope is steeper, can handle more thrust, and damps quicker at a lower frequency. The fuselage weight, or loading, affects thrust capacity and power-off sink rate, with heavier gliders capable of larger thrust inputs but faster descent speed; however, the glide slope remains unchanged. As the cg position is place forward of the attachment point the incidence angle and thrust line will rotate downward, while the opposite occurs moving aft. For the test vehicle, a slightly forward position allowed for the greatest thrust input, and far forward reduced performance for equivalent thrust compared to far aft. Three test

  17. Glutamate Metabolism in Brain Structures in Experimental Hemorrhagic Shock

    Directory of Open Access Journals (Sweden)

    V. N. Jakovlev

    2017-01-01

    Full Text Available Purpose. To study glutamate metabolism characteristics in phylogenetically different parts of the mammalian brain in experimentally induced hemorrhagic shock (HS in cats.Material and methods. Experiments were performed on 76 cats. HS was induced by intermittent bloodletting from femoral artery at a rate of 10ml/kg•10 minutes, with the average volume of 24±0.8 ml/kg. The bloodletting was discontinued after arterial pressure (BP drop to 60.0±1.5 mmHg. We studied ammonia, glutamate (Gt, and α-ketoglutarate (α-KG levels and glutaminase (GS and glutamate dehydrogenase (GDG activity in specimens harvested from phylogenetically different parts of the brain (cortex, limbic system, diencephalon, and medulla oblongata.Results. In intact animals, the peak GDG activity was found in the medulla oblongata (phylogenetically the oldest part of the brain and the peak GS activity was registered in the sensorimotor cortex (phylogenetically the youngest part of the brain; the glutaminase activity did not depend on the phylogenetic age of brain structures.In the case of HS, Gt metabolism changes began in the sensorimotor cortex manifested by decreased GS activity, which progresses by the 70th minute of the post%hemorrhagic period (PHP accompanied by delayed increase in the GDG and glutaminase activity, as well as Gt accumulation. In the limbic system and diencephalon the Gt metabolism was changing (impaired glutamine synthesis, stimuled Gt synthesis with glutamine desamidization and α%KG amination when developed by the 70th minute of the PHP. Similarly to sensorimotor cortex, changes were associated with Gt accumulation. During the agony, α%KG deficiency developed in all parts of the brain as a result of its increased contribution to Gt synthesis. At the same period of time, in the sensorimotor cortex, limbic system and diencephalon the Gt synthesis from glutamine was stimulated, however, the Gt contribution tothe formation of glutamine was decreased. The

  18. The use of Alloxan and Streptozotocin in Experimental Diabetes Models

    Directory of Open Access Journals (Sweden)

    Zehra Kurçer

    2012-06-01

    Full Text Available Diabetes is a chronic metabolic disease which leads to several acute and chronic complications, morbidity and mortality, and decreased lifespan and quality of life. Therefore, in research studies that aim to enlighten the pathogenesis of diabetes and investigate possible treatment strategies, experimental animal models of diabetes provide many advantages to the investigator. Models of diabetes obtained by chemical induction, diet, surgical manipulations or combination thereof and also new genetically modified animal models are some of the experimental models. Alloxan and streptozotocin (STZ, which are toxic glucose analogues that preferentially accumulate in pancreatic beta cells, are widely used toxic agents to induce experimental diabetes in animals. This review gives an overview on the use of alloxan and STZ to induce chemical diabetes models with reference to their mechanisms, utilizable doses, advantages and disadvantages in diabetes research. Turk Jem 2012; 16: 34-40

  19. Fire Response of Loaded Composite Structures - Experiments and Modeling

    OpenAIRE

    Burdette, Jason A.

    2001-01-01

    In this work, the thermo-mechanical response and failure of loaded, fire-exposed composite structures was studied. Unique experimental equipment and procedures were developed and experiments were performed to assess the effects of mechanical loading and fire exposure on the service life of composite beams. A series of analytical models was assembled to describe the fire growth and structural response processes for the system used in the experiments. This series of models consists of a fire...

  20. Evaluating experimental design for soil-plant model selection with Bayesian model averaging

    Science.gov (United States)

    Wöhling, Thomas; Geiges, Andreas; Nowak, Wolfgang; Gayler, Sebastian

    2013-04-01

    The objective selection of appropriate models for realistic simulations of coupled soil-plant processes is a challenging task since the processes are complex, not fully understood at larger scales, and highly non-linear. Also, comprehensive data sets are scarce, and measurements are uncertain. In the past decades, a variety of different models have been developed that exhibit a wide range of complexity regarding their approximation of processes in the coupled model compartments. We present a method for evaluating experimental design for maximum confidence in the model selection task. The method considers uncertainty in parameters, measurements and model structures. Advancing the ideas behind Bayesian Model Averaging (BMA), the model weights in BMA are perceived as uncertain quantities with assigned probability distributions that narrow down as more data are made available. This allows assessing the power of different data types, data densities and data locations in identifying the best model structure from among a suite of plausible models. The models considered in this study are the crop models CERES, SUCROS, GECROS and SPASS, which are coupled to identical routines for simulating soil processes within the modelling framework Expert-N. The four models considerably differ in the degree of detail at which crop growth and root water uptake are represented. Monte-Carlo simulations were conducted for each of these models considering their uncertainty in soil hydraulic properties and selected crop model parameters. The models were then conditioned on field measurements of soil moisture, leaf-area index (LAI), and evapotranspiration rates (from eddy-covariance measurements) during a vegetation period of winter wheat at the Nellingen site in Southwestern Germany. Following our new method, we derived the BMA model weights (and their distributions) when using all data or different subsets thereof. We discuss to which degree the posterior BMA mean outperformed the prior BMA

  1. Soil Retaining Structures : Development of models for structural analysis

    NARCIS (Netherlands)

    Bakker, K.J.

    2000-01-01

    The topic of this thesis is the development of models for the structural analysis of soil retaining structures. The soil retaining structures being looked at are; block revetments, flexible retaining walls and bored tunnels in soft soil. Within this context typical structural behavior of these

  2. Coordinated experimental/analytical program for investigating margins to failure of Category I reinforced concrete structures

    International Nuclear Information System (INIS)

    Endebrock, E.; Dove, R.; Anderson, C.A.

    1981-01-01

    The material presented in this paper deals with a coordinated experimental/analytical program designed to provide information needed for making margins to failure assessments of seismic Category I reinforced concrete structures. The experimental program is emphasized and background information that lead to this particular experimental approach is presented. Analytical tools being developed to supplement the experimental program are discussed. 16 figures

  3. Experimental and modeling studies of mass transfer in ...

    African Journals Online (AJOL)

    Gaining a better understanding of mass transfer problems in encapsulated cell systems and in tissue engineering requires both experimental investigations and mathematical modelling. Specific mass transfer studies are reviewed including oxygen transfer in immobilised animal cell culture systems, modelling of ...

  4. Experimental and Theoretical Studies of the Structures and Interactions of Vancomycin Antibiotics with Cell Wall Analogues

    International Nuclear Information System (INIS)

    Yang, Zhibo; Vorpagel, Erich R.; Laskin, Julia

    2008-01-01

    Surface-induced dissociation (SID) of the singly protonated complex of vancomycin antibiotic with cell wall peptide analogue (N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala) was studied using a 6 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FT-ICR MS) specially configured for SID experiments. The binding energy between the vancomycin and the peptide was obtained from the RRKM modeling of the time- and energy resolved fragmentation efficiency curves (TFECs) of the precursor ion and its fragments. Electronic structure calculations of the geometries, proton affinities and binding energies were performed for several model systems including vancomycin (V), vancomycin aglycon (VA), N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala, and non-covalent complexes of VA with N-acetyl-D-Ala-D-Ala and N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala at the B3LYP/6-31G(d) level of theory. Comparison between the experimental and computational results suggests that the most probable structure of the complex observed in our experiments corresponds to the neutral peptide bound to the vancomycin protonated at the secondary amino group of the N-methyl-leucine residue. The experimental binding energy of 30.9 ± 1.8 kcal/mol is in good agreement with the binding energy of 29.3 ± 2.5 kcal/mol calculated for the model system representing the preferred structure of the complex

  5. Structures of discoidal high density lipoproteins: a combined computational-experimental approach.

    Science.gov (United States)

    Gu, Feifei; Jones, Martin K; Chen, Jianguo; Patterson, James C; Catte, Andrea; Jerome, W Gray; Li, Ling; Segrest, Jere P

    2010-02-12

    Conversion of discoidal phospholipid (PL)-rich high density lipoprotein (HDL) to spheroidal cholesteryl ester-rich HDL is a central step in reverse cholesterol transport. A detailed understanding of this process and the atheroprotective role of apolipoprotein A-I (apoA-I) requires knowledge of the structure and dynamics of these various particles. This study, combining computation with experimentation, illuminates structural features of apoA-I allowing it to incorporate varying amounts of PL. Molecular dynamics simulated annealing of PL-rich HDL models containing unesterified cholesterol results in double belt structures with the same general saddle-shaped conformation of both our previous molecular dynamics simulations at 310 K and the x-ray structure of lipid-free apoA-I. Conversion from a discoidal to a saddle-shaped particle involves loss of helicity and formation of loops in opposing antiparallel parts of the double belt. During surface expansion caused by the temperature-jump step, the curved palmitoyloleoylphosphatidylcholine bilayer surfaces approach planarity. Relaxation back into saddle-shaped structures after cool down and equilibration further supports the saddle-shaped particle model. Our kinetic analyses of reconstituted particles demonstrate that PL-rich particles exist in discrete sizes corresponding to local energetic minima. Agreement of experimental and computational determinations of particle size/shape and apoA-I helicity provide additional support for the saddle-shaped particle model. Truncation experiments combined with simulations suggest that the N-terminal proline-rich domain of apoA-I influences the stability of PL-rich HDL particles. We propose that apoA-I incorporates increasing PL in the form of minimal surface bilayers through the incremental unwinding of an initially twisted saddle-shaped apoA-I double belt structure.

  6. Using an experimental model for the study of therapeutic touch.

    Science.gov (United States)

    dos Santos, Daniella Soares; Marta, Ilda Estéfani Ribeiro; Cárnio, Evelin Capellari; de Quadros, Andreza Urba; Cunha, Thiago Mattar; de Carvalho, Emilia Campos

    2013-02-01

    to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.

  7. Modeling of Cracked Beams by the Experimental Design Method

    Directory of Open Access Journals (Sweden)

    M. Serier

    Full Text Available Abstract The understanding of phenomena, no matter their nature is based on the experimental results found. In the most cases, this requires an important number of tests in order to put a reliable and useful observation served into solving the technical problems subsequently. This paper is based on independent and variables combination resulting from experimentation in a mathematical formulation. Indeed, mathematical modeling gives us the advantage to optimize and predict the right choices without passing each case by the experiment. In this work we plan to apply the experimental design method on the experimental results found by (Deokar, A, 2011, concerning the effect of the size and position of a crack on the measured frequency of a beam console, and validating the mathematical model to predict other frequencies

  8. Deep inelastic structure functions in the chiral bag model

    Energy Technology Data Exchange (ETDEWEB)

    Sanjose, V. (Valencia Univ. (Spain). Dept. de Didactica de las Ciencias Experimentales); Vento, V. (Valencia Univ. (Spain). Dept. de Fisica Teorica; Centro Mixto CSIC/Valencia Univ., Valencia (Spain). Inst. de Fisica Corpuscular)

    1989-10-02

    We calculate the structure functions for deep inelastic scattering on baryons in the cavity approximation to the chiral bag model. The behavior of these structure functions is analyzed in the Bjorken limit. We conclude that scaling is satisfied, but not Regge behavior. A trivial extension as a parton model can be achieved by introducing the structure function for the pion in a convolution picture. In this extended version of the model not only scaling but also Regge behavior is satisfied. Conclusions are drawn from the comparison of our results with experimental data. (orig.).

  9. Development of a fault test experimental facility model using Matlab

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Iraci Martinez; Moraes, Davi Almeida, E-mail: martinez@ipen.br, E-mail: dmoraes@dk8.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The Fault Test Experimental Facility was developed to simulate a PWR nuclear power plant and is instrumented with temperature, level and pressure sensors. The Fault Test Experimental Facility can be operated to generate normal and fault data, and these failures can be added initially small, and their magnitude being increasing gradually. This work presents the Fault Test Experimental Facility model developed using the Matlab GUIDE (Graphical User Interface Development Environment) toolbox that consists of a set of functions designed to create interfaces in an easy and fast way. The system model is based on the mass and energy inventory balance equations. Physical as well as operational aspects are taken into consideration. The interface layout looks like a process flowchart and the user can set the input variables. Besides the normal operation conditions, there is the possibility to choose a faulty variable from a list. The program also allows the user to set the noise level for the input variables. Using the model, data were generated for different operational conditions, both under normal and fault conditions with different noise levels added to the input variables. Data generated by the model will be compared with Fault Test Experimental Facility data. The Fault Test Experimental Facility theoretical model results will be used for the development of a Monitoring and Fault Detection System. (author)

  10. Development of a fault test experimental facility model using Matlab

    International Nuclear Information System (INIS)

    Pereira, Iraci Martinez; Moraes, Davi Almeida

    2015-01-01

    The Fault Test Experimental Facility was developed to simulate a PWR nuclear power plant and is instrumented with temperature, level and pressure sensors. The Fault Test Experimental Facility can be operated to generate normal and fault data, and these failures can be added initially small, and their magnitude being increasing gradually. This work presents the Fault Test Experimental Facility model developed using the Matlab GUIDE (Graphical User Interface Development Environment) toolbox that consists of a set of functions designed to create interfaces in an easy and fast way. The system model is based on the mass and energy inventory balance equations. Physical as well as operational aspects are taken into consideration. The interface layout looks like a process flowchart and the user can set the input variables. Besides the normal operation conditions, there is the possibility to choose a faulty variable from a list. The program also allows the user to set the noise level for the input variables. Using the model, data were generated for different operational conditions, both under normal and fault conditions with different noise levels added to the input variables. Data generated by the model will be compared with Fault Test Experimental Facility data. The Fault Test Experimental Facility theoretical model results will be used for the development of a Monitoring and Fault Detection System. (author)

  11. The Protein Model Portal--a comprehensive resource for protein structure and model information.

    Science.gov (United States)

    Haas, Juergen; Roth, Steven; Arnold, Konstantin; Kiefer, Florian; Schmidt, Tobias; Bordoli, Lorenza; Schwede, Torsten

    2013-01-01

    The Protein Model Portal (PMP) has been developed to foster effective use of 3D molecular models in biomedical research by providing convenient and comprehensive access to structural information for proteins. Both experimental structures and theoretical models for a given protein can be searched simultaneously and analyzed for structural variability. By providing a comprehensive view on structural information, PMP offers the opportunity to apply consistent assessment and validation criteria to the complete set of structural models available for proteins. PMP is an open project so that new methods developed by the community can contribute to PMP, for example, new modeling servers for creating homology models and model quality estimation servers for model validation. The accuracy of participating modeling servers is continuously evaluated by the Continuous Automated Model EvaluatiOn (CAMEO) project. The PMP offers a unique interface to visualize structural coverage of a protein combining both theoretical models and experimental structures, allowing straightforward assessment of the model quality and hence their utility. The portal is updated regularly and actively developed to include latest methods in the field of computational structural biology. Database URL: http://www.proteinmodelportal.org.

  12. The Protein Model Portal—a comprehensive resource for protein structure and model information

    Science.gov (United States)

    Haas, Juergen; Roth, Steven; Arnold, Konstantin; Kiefer, Florian; Schmidt, Tobias; Bordoli, Lorenza; Schwede, Torsten

    2013-01-01

    The Protein Model Portal (PMP) has been developed to foster effective use of 3D molecular models in biomedical research by providing convenient and comprehensive access to structural information for proteins. Both experimental structures and theoretical models for a given protein can be searched simultaneously and analyzed for structural variability. By providing a comprehensive view on structural information, PMP offers the opportunity to apply consistent assessment and validation criteria to the complete set of structural models available for proteins. PMP is an open project so that new methods developed by the community can contribute to PMP, for example, new modeling servers for creating homology models and model quality estimation servers for model validation. The accuracy of participating modeling servers is continuously evaluated by the Continuous Automated Model EvaluatiOn (CAMEO) project. The PMP offers a unique interface to visualize structural coverage of a protein combining both theoretical models and experimental structures, allowing straightforward assessment of the model quality and hence their utility. The portal is updated regularly and actively developed to include latest methods in the field of computational structural biology. Database URL: http://www.proteinmodelportal.org PMID:23624946

  13. Investigation of wax precipitation in crude oil: Experimental and modeling

    Directory of Open Access Journals (Sweden)

    Taraneh Jafari Behbahani

    2015-09-01

    Full Text Available In this work, a series of experiments were carried to investigation of rheological behavior of crude oil using waxy crude oil sample in the absence/presence of flow improver such as ethylene-vinyl acetate copolymer. The rheological data covered the temperature range of 5–30 °C. The results indicated that the performance of flow improver was dependent on its molecular weight. Addition of small quantities of flow improver, can improve viscosity and pour point of crude oil. Also, an Artificial Neural Network (ANN model using Multi-Layer Perceptron (MLP topology has been developed to account wax appearance temperature and the amount of precipitated wax and the model was verified using experimental data given in this work and reported in the literature. In order to compare the performance of the proposed model based on Artificial Neural Network, the wax precipitation experimental data at different temperatures were predicted using solid solution model and multi-solid phase model. The results showed that the developed model based on Artificial Neural Network can predict more accurately the wax precipitation experimental data in comparison to the previous models such as solid solution and multi-solid phase model with AADs less than 0.5%. Furthermore, the number of parameters required for the Artificial Neural Network (ANN model is less than the studied thermodynamic models.

  14. Numerical Modeling and Experimental Testing of a Wave Energy Converter

    DEFF Research Database (Denmark)

    Zurkinden, Andrew Stephen; Kramer, Morten; Ferri, Francesco

    numerical values for comparison with the experimental test results which were carried out in the same time. It is for this reason why Chapter 4 does consist exclusively of numerical values. Experimental values and measured time series of wave elevations have been used throughout the report in order to a......) validate the numerical model and b) preform stochastic analysis. The latter technique is introduced in order to optimize the control parameters of the power take off system....

  15. Experimental Errors in QSAR Modeling Sets: What We Can Do and What We Cannot Do.

    Science.gov (United States)

    Zhao, Linlin; Wang, Wenyi; Sedykh, Alexander; Zhu, Hao

    2017-06-30

    Numerous chemical data sets have become available for quantitative structure-activity relationship (QSAR) modeling studies. However, the quality of different data sources may be different based on the nature of experimental protocols. Therefore, potential experimental errors in the modeling sets may lead to the development of poor QSAR models and further affect the predictions of new compounds. In this study, we explored the relationship between the ratio of questionable data in the modeling sets, which was obtained by simulating experimental errors, and the QSAR modeling performance. To this end, we used eight data sets (four continuous endpoints and four categorical endpoints) that have been extensively curated both in-house and by our collaborators to create over 1800 various QSAR models. Each data set was duplicated to create several new modeling sets with different ratios of simulated experimental errors (i.e., randomizing the activities of part of the compounds) in the modeling process. A fivefold cross-validation process was used to evaluate the modeling performance, which deteriorates when the ratio of experimental errors increases. All of the resulting models were also used to predict external sets of new compounds, which were excluded at the beginning of the modeling process. The modeling results showed that the compounds with relatively large prediction errors in cross-validation processes are likely to be those with simulated experimental errors. However, after removing a certain number of compounds with large prediction errors in the cross-validation process, the external predictions of new compounds did not show improvement. Our conclusion is that the QSAR predictions, especially consensus predictions, can identify compounds with potential experimental errors. But removing those compounds by the cross-validation procedure is not a reasonable means to improve model predictivity due to overfitting.

  16. Models and structures: mathematical physics

    International Nuclear Information System (INIS)

    2003-01-01

    This document gathers research activities along 5 main directions. 1) Quantum chaos and dynamical systems. Recent results concern the extension of the exact WKB method that has led to a host of new results on the spectrum and wave functions. Progress have also been made in the description of the wave functions of chaotic quantum systems. Renormalization has been applied to the analysis of dynamical systems. 2) Combinatorial statistical physics. We see the emergence of new techniques applied to various such combinatorial problems, from random walks to random lattices. 3) Integrability: from structures to applications. Techniques of conformal field theory and integrable model systems have been developed. Progress is still made in particular for open systems with boundary conditions, in connection to strings and branes physics. Noticeable links between integrability and exact WKB quantization to 2-dimensional disordered systems have been highlighted. New correlations of eigenvalues and better connections to integrability have been formulated for random matrices. 4) Gravities and string theories. We have developed aspects of 2-dimensional string theory with a particular emphasis on its connection to matrix models as well as non-perturbative properties of M-theory. We have also followed an alternative path known as loop quantum gravity. 5) Quantum field theory. The results obtained lately concern its foundations, in flat or curved spaces, but also applications to second-order phase transitions in statistical systems

  17. Models and structures: mathematical physics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This document gathers research activities along 5 main directions. 1) Quantum chaos and dynamical systems. Recent results concern the extension of the exact WKB method that has led to a host of new results on the spectrum and wave functions. Progress have also been made in the description of the wave functions of chaotic quantum systems. Renormalization has been applied to the analysis of dynamical systems. 2) Combinatorial statistical physics. We see the emergence of new techniques applied to various such combinatorial problems, from random walks to random lattices. 3) Integrability: from structures to applications. Techniques of conformal field theory and integrable model systems have been developed. Progress is still made in particular for open systems with boundary conditions, in connection to strings and branes physics. Noticeable links between integrability and exact WKB quantization to 2-dimensional disordered systems have been highlighted. New correlations of eigenvalues and better connections to integrability have been formulated for random matrices. 4) Gravities and string theories. We have developed aspects of 2-dimensional string theory with a particular emphasis on its connection to matrix models as well as non-perturbative properties of M-theory. We have also followed an alternative path known as loop quantum gravity. 5) Quantum field theory. The results obtained lately concern its foundations, in flat or curved spaces, but also applications to second-order phase transitions in statistical systems.

  18. Optimal experimental designs for inverse quadratic regression models

    OpenAIRE

    Dette, Holger; Kiss, Christine

    2007-01-01

    In this paper optimal experimental designs for inverse quadratic regression models are determined. We consider two different parameterizations of the model and investigate local optimal designs with respect to the $c$-, $D$- and $E$-criteria, which reflect various aspects of the precision of the maximum likelihood estimator for the parameters in inverse quadratic regression models. In particular it is demonstrated that for a sufficiently large design space geometric allocation rules are optim...

  19. Ion thruster modeling: Particle simulations and experimental validations

    International Nuclear Information System (INIS)

    Wang, Joseph; Polk, James; Brinza, David

    2003-01-01

    This paper presents results from ion thruster modeling studies performed in support of NASA's Deep Space 1 mission and NSTAR project. Fully 3-dimensional computer particle simulation models are presented for ion optics plasma flow and ion thruster plume. Ion optics simulation results are compared with measurements obtained from ground tests of the NSTAR ion thruster. Plume simulation results are compared with in-flight measurements from the Deep Space 1 spacecraft. Both models show excellent agreement with experimental data

  20. Modeling experimental plasma diagnostics in the FLASH code: proton radiography

    Science.gov (United States)

    Flocke, Norbert; Weide, Klaus; Feister, Scott; Tzeferacos, Petros; Lamb, Donald

    2017-10-01

    Proton radiography is an important diagnostic tool for laser plasma experiments and for studying magnetized plasmas. We describe a new synthetic proton radiography diagnostic recently implemented into the FLASH code. FLASH is an open source, finite-volume Eulerian, spatially adaptive radiation hydrodynamics and magneto-hydrodynamics code that incorporates capabilities for a broad range of physical processes. Proton radiography is modeled through the use of the (relativistic) Lorentz force equation governing the motion of protons through 3D domains. Both instantaneous (one time step) and time-resolved (over many time steps) proton radiography can be simulated. The code module is also equipped with several different setup options (beam structure and detector screen placements) to reproduce a large variety of experimental proton radiography designs. FLASH's proton radiography diagnostic unit can be used either during runtime or in post-processing of simulation results. FLASH is publicly available at flash.uchicago.edu. U.S. DOE NNSA, U.S. DOE NNSA ASC, U.S. DOE Office of Science and NSF.

  1. Models of protein-ligand crystal structures: trust, but verify

    Science.gov (United States)

    Deller, Marc C.; Rupp, Bernhard

    2015-09-01

    X-ray crystallography provides the most accurate models of protein-ligand structures. These models serve as the foundation of many computational methods including structure prediction, molecular modelling, and structure-based drug design. The success of these computational methods ultimately depends on the quality of the underlying protein-ligand models. X-ray crystallography offers the unparalleled advantage of a clear mathematical formalism relating the experimental data to the protein-ligand model. In the case of X-ray crystallography, the primary experimental evidence is the electron density of the molecules forming the crystal. The first step in the generation of an accurate and precise crystallographic model is the interpretation of the electron density of the crystal, typically carried out by construction of an atomic model. The atomic model must then be validated for fit to the experimental electron density and also for agreement with prior expectations of stereochemistry. Stringent validation of protein-ligand models has become possible as a result of the mandatory deposition of primary diffraction data, and many computational tools are now available to aid in the validation process. Validation of protein-ligand complexes has revealed some instances of overenthusiastic interpretation of ligand density. Fundamental concepts and metrics of protein-ligand quality validation are discussed and we highlight software tools to assist in this process. It is essential that end users select high quality protein-ligand models for their computational and biological studies, and we provide an overview of how this can be achieved.

  2. Experimental models of transfusion-related acute lung injury.

    Science.gov (United States)

    Gilliss, Brian M; Looney, Mark R

    2011-01-01

    Transfusion-related acute lung injury (TRALI) is defined clinically as acute lung injury occurring within six hours of the transfusion of any blood product. It is the leading cause of transfusion-related death in the United States, but under-recognition and diagnostic uncertainty have limited clinical research to smaller case control studies. In this review we discuss the contribution of experimental models to the understanding of TRALI pathophysiology and potential therapeutic approaches. Experimental models suggest that TRALI occurs when a host, with a primed immune system, is exposed to an activating agent such as anti-leukocyte antibody or a biologic response modifier such as lysophosphatidylcholines. Recent work has suggested a critical role for platelets in antibody-based experimental models and identified potential therapeutic strategies for TRALI. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Experimental Models of Transfusion-Related Acute Lung Injury (TRALI)

    Science.gov (United States)

    Gilliss, Brian M.; Looney, Mark R.

    2010-01-01

    Transfusion-related acute lung injury (TRALI) is defined clinically as acute lung injury occurring within six hours of the transfusion of any blood product. It is the leading cause of transfusion-related death in the United States, but under-recognition and diagnostic uncertainty have limited clinical research to smaller case control studies. In this review we will discuss the contribution of experimental models to the understanding of TRALI pathophysiology and potential therapeutic approaches. Experimental models suggest that TRALI occurs when a host, with a primed immune system, is exposed to an activating agent such as anti-leukocyte antibody or a biologic response modifier such as lysophosphatidylcholines. Recent work has suggested a critical role for platelets in antibody-based experimental models and identified potential therapeutic strategies for TRALI. PMID:21134622

  4. Structural Response of Submerged Air-Backed Plates by Experimental and Numerical Analyses

    Directory of Open Access Journals (Sweden)

    Lloyd Hammond

    2000-01-01

    Full Text Available This paper presents the results of a series of small-scale underwater shock experiments that measured the structural responses of submerged, fully clamped, air-backed, steel plates to a range of high explosive charge sizes. The experimental results were subsequently used to validate a series of simulations using the coupled LS-DYNA/USA finite element/boundary element codes. The modelling exercise was complicated by a significant amount of local cavitation occurring in the fluid adjacent to the plate and difficulties in modelling the boundary conditions of the test plates. The finite element model results satisfactorily predicted the displacement-time history of the plate over a range of shock loadings although a less satisfactory correlation was achieved for the peak velocities. It is expected that the predictive capability of the finite element model will be significantly improved once hydrostatic initialisation can be fully utilised with the LS-DYNA/USA software.

  5. Likelihood-based modification of experimental crystal structure electron density maps

    Science.gov (United States)

    Terwilliger, Thomas C [Sante Fe, NM

    2005-04-16

    A maximum-likelihood method for improves an electron density map of an experimental crystal structure. A likelihood of a set of structure factors {F.sub.h } is formed for the experimental crystal structure as (1) the likelihood of having obtained an observed set of structure factors {F.sub.h.sup.OBS } if structure factor set {F.sub.h } was correct, and (2) the likelihood that an electron density map resulting from {F.sub.h } is consistent with selected prior knowledge about the experimental crystal structure. The set of structure factors {F.sub.h } is then adjusted to maximize the likelihood of {F.sub.h } for the experimental crystal structure. An improved electron density map is constructed with the maximized structure factors.

  6. Magnetic field structure of experimental high beta tokamak equilibria

    International Nuclear Information System (INIS)

    Deniz, A.V.

    1986-01-01

    The magnetic field structure of several low and high β tokamaks in the Columbia High Beta Tokamak (HBT) was determined by high-impedance internal magnetic probes. From the measurement of the magnetic field, the poloidal flux, toroidal flux, toroidal current, and safety factor are calculated. In addition, the plasma position and cross-sectional shape are determined. The extent of the perturbation of the plasma by the probe was investigated and was found to be acceptably small. The tokamaks have major radii of approx.0.24 m, minor radii of approx.0.05 m, toroidal plasma current densities of approx.10 6 A/m 2 , and line-integrated electron densities of approx.10 20 m -2 . The major difference between the low and high β tokamaks is that the high β tokamak was observed to have an outward shift in major radius of both the magnetic center and peak of the toroidal current density. The magnetic center moves inward in major radius after 20 to 30 μsec, presumably because the plasma maintains major radial equilibrium as its pressure decreases from radiation due to impurity atoms. Both the equilibrium and the production of these tokamaks from a toroidal field stabilized z-pinch are modeled computationally. One tokamak evolves from a state with low β features, through a possibly unstable state, to a state with high β features

  7. Experimental modeling of injectivity loss; Modelagem experimental da perda de injetividade

    Energy Technology Data Exchange (ETDEWEB)

    Bonato, Adriano Jose do Amaral Mello; Silva, Pedro Glauto de Farias e; Gomes, Vanessa Limeira Azevedo; Santos, Adriano dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2012-07-01

    Produced water reinjection, suspended particles are retained in the porous media causing formation damage and injectivity decline. In general the retention of the particles occurs near the side of injection, this fact occurs in most cases, due to the size exclusion. The modeling of filtration and the consequent formation damage is essential to the project management of water injection in oil reservoirs. Thus, mathematical models are studied to better predict the distribution of particles throughout the porous media and determine the parameters of adjustment to injectivity decline. Among these models, there is the classic model which consists in determining these parameters (coefficient of filtration and formation damage). The methodology used in modeling is given from the equations the mass conservation, kinetic particle retention, the modified Darcy equation and the function formation damage. This study aimed to improve experimental modeling, including development of software for acquisition and processing of experimental data, considering the variable number of pressure measurements along the sample. The software was developed using the Labview 2011 platform and allows the determination of relevant parameters to predict injectivity loss in water injection wells. Furthermore, based on the traditional model of filtration in porous media (including depth filtration and formation of the external plaster), the software was applied to predict injectivity loss in addition to the properties of the grout. Finally, the classical models for transporting suspensions and damage to the formation were observed. (author)

  8. Experimental and analytical study on buckling of fluid-coupled structures during a seismic load

    International Nuclear Information System (INIS)

    Barthelet, B.; Geoffroy, P.

    1988-01-01

    Seismic analysis of a liquid metal fast breeder reactor is generally made with a linear dynamic model. The structure response is a combination of modes n=1 for horizontal earthquakes and n=0 for vertical earthquakes. The resulting loading is used for stability calculation on ''static equivalent'' models. This procedure may not be correct for two main reasons: geometrical defects and large displacements could change significantly the behaviour of the structures; the dynamic buckling pressure could be different from the static buckling pressure. To answer these questions, an experimental and analytical study on buckling of fluid-coupled structures during a seismic load has been performed by Electricite de France, the Commissariat a l'Energie Atomique and the Universite de Compiegne. The experiments are made on semi-spherical and cylindrical shells on a vibrating table; the loading applied to the structures consists of a permanent pressure and of a dynamic pressure due to fluid-structure interaction. The experimental results are presented and compared with the calculations. This study presents four main points: the dynamic pressure does not vary linearly with the shaking-table acceleration; at high acceleration level, the dynamic pressure increases very slowly; the prestress due to permanent pressure can have a significant effect on the eigenfrequencies if the buckling modes are colinear to the vibration modes; for hemispherical shells studied here, the buckling is obtained when the sum of permanent pressure and dynamic pressure is greater than the static buckling pressure; this structure excited with a horizontal motion can have a response in circumferential modes and not only in mode 1 as predicted by the theory of perfect shells. The defects explain the coupling of modes. (author). 9 figs, 6 tabs, 2 photos

  9. Additive-manufactured sandwich lattice structures: A numerical and experimental investigation

    Science.gov (United States)

    Fergani, Omar; Tronvoll, Sigmund; Brøtan, Vegard; Welo, Torgeir; Sørby, Knut

    2017-10-01

    The utilization of additive-manufactured lattice structures in engineered products is becoming more and more common as the competitiveness of AM as a production technology has increased during the past several years. Lattice structures may enable important weight reductions as well as open opportunities to build products with customized functional properties, thanks to the flexibility of AM for producing complex geometrical configurations. One of the most critical aspects related to taking AM into new application areas—such as safety critical products—is currently the limited understanding of the mechanical behavior of sandwich-based lattice structure mechanical under static and dynamic loading. In this study, we evaluate manufacturability of lattice structures and the impact of AM processing parameters on the structural behavior of this type of sandwich structures. For this purpose, we conducted static compression testing for a variety of geometry and manufacturing parameters. Further, the study discusses a numerical model capable of predicting the behavior of different lattice structure. A reasonably good correlation between the experimental and numerical results was observed.

  10. Development of the tube bundle structure for fluid-structure interaction analysis model - Intermediate Report -

    International Nuclear Information System (INIS)

    Yoon, Kyung Ho; Kim, Jae Yong; Lee, Kang Hee; Lee, Young Ho; Kim, Hyung Kyu

    2009-07-01

    Tube bundle structures within a Boiler or heat exchanger are laid the fluid-structure, thermal-structure and fluid-thermal-structure coupled boundary condition. In these complicated boundary conditions, Fluid-structure interaction (FSI) occurs when fluid flow causes deformation of the structure. This deformation, in turn, changes the boundary conditions for the fluid flow. The structural analysis have been executed as follows. First of all, divide the fluid and structural analysis discipline, and then independently analyzed each other. However, the fluid dynamic force effect the behavior of the structure, and the vibration amplitude of the structure to fluid. FSI analysis model was separately created fluid and structure model, and then defined the fsi boundary condition, and simultaneously analyzed in one domain. The analysis results were compared with those of the experimental method for validating the analysis model. Flow-induced vibration test was executed with single rod configuration. The vibration amplitudes of a fuel rod were measured by the laser vibro-meter system in x and y-direction. The analyses results were not closely with the test data, but the trend was very similar with the test result. In fsi coupled analysis case, the turbulent model was very important with the reliability of the accuracy of the analysis model. Therefore, the analysis model will be needed to further study

  11. Experimental measurements and thermodynamic modeling of refrigerant hydrates dissociation conditions

    International Nuclear Information System (INIS)

    Hashemi, Hamed; Babaee, Saeedeh; Mohammadi, Amir H.; Naidoo, Paramespri; Ramjugernath, Deresh

    2015-01-01

    Highlights: • Dissociation conditions of refrigerant hydrates are studied experimentally and theoretically. • Refrigerants R23, R134a, R125a, R22, R410A, R407C and R507C are studied experimentally. • A thermodynamic model able to predict refrigerant hydrates dissociation conditions is proposed. • The results show good agreement between the experimental and predicted values. - Abstract: This study aims to investigate dissociation conditions of refrigerant hydrates both experimentally and theoretically. For this purpose, dissociation conditions of refrigerants R23, R134a, R125a, R22, R410A, R407C and R507C have been measured experimentally. A thermodynamic model that is able to predict refrigerant hydrates dissociation conditions in the various phase equilibrium regions has been proposed as well. Refrigerants modeled in this study include pure refrigerants: R11, R12, R13, R22, R23, R32, R134a, R141b, R143a, R125a, R152a, and mixed refrigerants: R11 + R12, R11 + R114, R12 + R114, R32 + R125a + R134a (R407C), R32 + R125a (R410A). For the modeling of the fluid and hydrate phases, the Peng-Robinson equation of state modified by Stryjek and Vera and the MHV2 G E -EoS mixing rule along with the UNIFAC (original) activity coefficient and van der Waals–Platteeuw (vdW–P) models were employed. The results show good agreement between the experimental and predicted values

  12. Team Modelling: Review of Experimental Scenarios and Computational Models

    Science.gov (United States)

    2006-09-01

    architecture on naturalistic decision making performance, University of Adelaide: Unpublished Honors Thesis . Chapman, T., Mills V., Kardos M., Stothard C...management structure and communication architecture on naturalistic decision making performance, University of Adelaide: Unpublished Honours Thesis ...can fire at any given time. In addition to the above information, friendly intelligence reports that the enemy is using five hovercraft air scouts

  13. Structural dynamic modifications via models

    Indian Academy of Sciences (India)

    2nd Int. Modal Analysis Conference (Orlando) 2: 930±936. Natke H G (ed.) 1982 Identification of vibrating structures (New York: Springer Verlag, Wein). Rao S S 1989 Optimum design of structures under shock and vibration environment. Shock Vibr. Dig. 21(7):. Ravi S S A 1994 Structural dynamic modifications and design ...

  14. Experimental studies and modeling of an information embedded power system

    Science.gov (United States)

    Carullo, Stephen Paul

    This thesis develops a model of an electrical power system, with its inherent embedded communication system, for studying the characteristics of power system measurement errors due to communication delays. This model is referred to as an "information embedded power system" to emphasize the addition of a model of the communication system, that delivers measurements to a control center, to the standard model for the energy balance within the power system. These power system measurements are delivered across an Ethernet computer control network. An experimental platform was created in order to experimentally measure and characterize measurement delay errors (MDEs) in this information embedded power system. Several stochastic system models are developed, which are composed of both the physical infrastructure of the power system as well as the embedded computer network communication infrastructure. Both white noise and colored noise models are used to characterize MDEs. This type of analysis is an extension of traditional observability approaches, which usually only assume deterministic steady-state conditions in the power system and do not consider time delays in delivering measurements. The experimental platform is used to validate the developed model.

  15. Local linear model tree and Neuro-Fuzzy system for modelling and control of an experimental pH neutralization process

    Directory of Open Access Journals (Sweden)

    G. Petchinathan

    2014-06-01

    Full Text Available This paper describes the modelling and control of a pH neutralization process using a Local Linear Model Tree (LOLIMOT and an adaptive neuro-fuzzy inference system (ANFIS. The Direct and Inverse model building using LOLIMOT and ANFIS structures is described and compared. The direct and inverse models of the pH system are identified based on experimental data for the LOLIMOT and ANFIS structures. The identified models are implemented in the experimental pH system with IMC structure using a GUI developed in the MATLAB -SIMULINK platform. The main aim is to illustrate the online modelling and control of the experimental setup. The results of real-time control of an experimental pH process using the Internal Model Control (IMC strategy are also presented.

  16. Probabilistic models and machine learning in structural bioinformatics.

    Science.gov (United States)

    Hamelryck, Thomas

    2009-10-01

    Structural bioinformatics is concerned with the molecular structure of biomacromolecules on a genomic scale, using computational methods. Classic problems in structural bioinformatics include the prediction of protein and RNA structure from sequence, the design of artificial proteins or enzymes, and the automated analysis and comparison of biomacromolecules in atomic detail. The determination of macromolecular structure from experimental data (for example coming from nuclear magnetic resonance, X-ray crystallography or small angle X-ray scattering) has close ties with the field of structural bioinformatics. Recently, probabilistic models and machine learning methods based on Bayesian principles are providing efficient and rigorous solutions to challenging problems that were long regarded as intractable. In this review, I will highlight some important recent developments in the prediction, analysis and experimental determination of macromolecular structure that are based on such methods. These developments include generative models of protein structure, the estimation of the parameters of energy functions that are used in structure prediction, the superposition of macromolecules and structure determination methods that are based on inference. Although this review is not exhaustive, I believe the selected topics give a good impression of the exciting new, probabilistic road the field of structural bioinformatics is taking.

  17. Experimental and modeling studies of clay/polydicyclopentadiene resin nanocomposites

    Science.gov (United States)

    Yoonessi, Mitra

    Hybrid organic-inorganic nanocomposites have received considerable attention during the last five years due to their unexpected properties. This work incorporated nanodispersed organically modified montmorillonite clay into polydicyclopentadiene resin matrices. Montmorillonite consists of 1 nm platelet sheets with a 2:1 structure, consisting of an alumina octahedral layer sandwiched between two silica tetrahedral layers. The relative weak forces between platelets allow small molecules like water, solvents and monomers as well as polymers, to enter into the interlayer spacings between the platelet sheets. In-situ polymerization of highly delaminated clay/dicyclopentadiene (DCPD) dispersions was used to prepare clay/polydicyclopentadiene (polyDCPD) nanocomposites. Highly delaminated composites were characterized using X-ray diffraction, X-ray scattering and high resolution TEM. Composites with 0.5--1 weight percent of clay had higher Tg values and flexural moduli. The flow properties of the organically-modified montmorillonite/DCPD liquid dispersions were examined using a co-rotating viscometer. The dispersions with clay concentrations higher than 0.5wt% clay in DCPD showed thixotropic flow behavior. Small angle neutron scattering (SANS) experiments were performed to obtain anisotropic scattering of highly delaminated clay in DCPD due to the orientation of clay platelets and tactoids in the shear field. No anisotropic scattering was observed. The reason for this unexpected result is not yet understood. Highly delaminated organically-modified clay composites were examined using small angle neutron scattering (SANS) and ultra small angle neutron scattering (USANS). The SANS data from 0.5, 1 and 2wt% clay/polyDCPD composites with 2 different types of clay were fitted to the stacked disk model. The average number of clay layers per tactoid was predicted by fitting the experimental data to the stacked disk model. Extensive high-resolution TEM analyses were performed on

  18. Instrumental and ethical aspects of experimental research with animal models

    Directory of Open Access Journals (Sweden)

    Mirian Watanabe

    2014-02-01

    Full Text Available Experimental animal models offer possibilities of physiology knowledge, pathogenesis of disease and action of drugs that are directly related to quality nursing care. This integrative review describes the current state of the instrumental and ethical aspects of experimental research with animal models, including the main recommendations of ethics committees that focus on animal welfare and raises questions about the impact of their findings in nursing care. Data show that, in Brazil, the progress in ethics for the use of animals for scientific purposes was consolidated with Law No. 11.794/2008 establishing ethical procedures, attending health, genetic and experimental parameters. The application of ethics in handling of animals for scientific and educational purposes and obtaining consistent and quality data brings unquestionable contributions to the nurse, as they offer subsidies to relate pathophysiological mechanisms and the clinical aspect on the patient.

  19. Updating Finite Element Model of a Wind Turbine Blade Section Using Experimental Modal Analysis Results

    Directory of Open Access Journals (Sweden)

    Marcin Luczak

    2014-01-01

    Full Text Available This paper presents selected results and aspects of the multidisciplinary and interdisciplinary research oriented for the experimental and numerical study of the structural dynamics of a bend-twist coupled full scale section of a wind turbine blade structure. The main goal of the conducted research is to validate finite element model of the modified wind turbine blade section mounted in the flexible support structure accordingly to the experimental results. Bend-twist coupling was implemented by adding angled unidirectional layers on the suction and pressure side of the blade. Dynamic test and simulations were performed on a section of a full scale wind turbine blade provided by Vestas Wind Systems A/S. The numerical results are compared to the experimental measurements and the discrepancies are assessed by natural frequency difference and modal assurance criterion. Based on sensitivity analysis, set of model parameters was selected for the model updating process. Design of experiment and response surface method was implemented to find values of model parameters yielding results closest to the experimental. The updated finite element model is producing results more consistent with the measurement outcomes.

  20. Mechanisms of Osteoarthritic Pain. Studies in Humans and Experimental Models

    Directory of Open Access Journals (Sweden)

    Annett Eitner

    2017-11-01

    Full Text Available Pain due to osteoarthritis (OA is one of the most frequent causes of chronic pain. However, the mechanisms of OA pain are poorly understood. This review addresses the mechanisms which are thought to be involved in OA pain, derived from studies on pain mechanisms in humans and in experimental models of OA. Three areas will be considered, namely local processes in the joint associated with OA pain, neuronal mechanisms involved in OA pain, and general factors which influence OA pain. Except the cartilage all structures of the joints are innervated by nociceptors. Although the hallmark of OA is the degradation of the cartilage, OA joints show multiple structural alterations of cartilage, bone and synovial tissue. In particular synovitis and bone marrow lesions have been proposed to determine OA pain whereas the contribution of the other pathologies to pain generation has been studied less. Concerning the peripheral neuronal mechanisms of OA pain, peripheral nociceptive sensitization was shown, and neuropathic mechanisms may be involved at some stages. Structural changes of joint innervation such as local loss and/or sprouting of nerve fibers were shown. In addition, central sensitization, reduction of descending inhibition, descending excitation and cortical atrophies were observed in OA. The combination of different neuronal mechanisms may define the particular pain phenotype in an OA patient. Among mediators involved in OA pain, nerve growth factor (NGF is in the focus because antibodies against NGF significantly reduce OA pain. Several studies show that neutralization of interleukin-1β and TNF may reduce OA pain. Many patients with OA exhibit comorbidities such as obesity, low grade systemic inflammation and diabetes mellitus. These comorbidities can significantly influence the course of OA, and pain research just began to study the significance of such factors in pain generation. In addition, psychologic and socioeconomic factors may aggravate

  1. THEORETICAL AND EXPERIMENTAL STUDY OF STRUCTURES SUBJECTED TO EARTHQUAKES

    Energy Technology Data Exchange (ETDEWEB)

    Soubirou, A.

    1967-12-31

    The object of the study was the investigation of the behaviour of structures subject to earthquakes. After .describing and analysing seismic movements, useful concepts for earthquake-proofing structures are lintroduced. Then, the dynamic behaviour of systems with n degrees of freedom was studied in order to evolve the theoretical computation of seismic behaviour, a typical application being reticulated structures. The next stage was showing the computational procedure for seismic spectra and the natural frequencies of buildings, an attempt being made to define earthquake-proofing criteria for a special type of reinforced-concrete construction. . The last matter dealt with is elastoplastic behaviour of structures, a study of increasingly growing importance.

  2. Numerical and Experimental Modeling of the Static Response of ...

    African Journals Online (AJOL)

    This paper presents numerical and experimental modeling of the static response of simply supported thin-walled reinforced concrete box girder bridges. The work is executed to verify the validity of software developed by the authors for the finite strip analysis of continuous thin-walled box girder bridges and also to observe ...

  3. Experimental Analysis and Model Validation of an Opaque Ventilated Facade

    DEFF Research Database (Denmark)

    López, F. Peci; Jensen, Rasmus Lund; Heiselberg, Per

    2012-01-01

    Natural ventilation is a convenient way of reducing energy consumption in buildings. In this study an experimental module of an opaque ventilated façade (OVF) was built and tested for assessing its potential of supplying free ventilation and air preheating for the building. A numerical model was ...

  4. Active Photonic Crystal Switches: Modeling, Design and Experimental Characterization

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Yu, Yi; Kristensen, Philip Trøst

    2013-01-01

    In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed...

  5. An Interactive Multimedia Based Instruction in Experimental Modelling

    DEFF Research Database (Denmark)

    Knudsen, Morten; Nielsen, J.N.; Østergaard, J.

    1997-01-01

    A CD-ROM based interactive multimedia instruction in experimental modelling for Danish Engineering School teachers is described. The content is based on a new sensitivity approach for direct estimation of physical parameters in linear and nonlinear dynamic systems. The presentation is inspired...

  6. Novel sensors for food inspection modelling, fabrication and experimentation

    CERN Document Server

    Abdul Rahman, Mohd Syaifudin; Yu, Pak-Lam

    2014-01-01

    This book addresses presents recent developments of novel planar interdigital sensors for food inspection. It covers the fundamentals of sensors, their design, modelling and simulations, fabrications, characterizations, experimental investigations and analyses. This book will be useful for the engineers and researchers especially higher undergraduate, postgraduate students as well as practitioners working on the development of Electromagnetic Sensors.

  7. Endogenous opioid antagonism in physiological experimental pain models

    DEFF Research Database (Denmark)

    Werner, Mads U; Pereira, Manuel P; Andersen, Lars Peter H

    2015-01-01

    Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double...

  8. Capillary microreactors for lactic acid extraction: experimental and modelling study

    NARCIS (Netherlands)

    Susanti, Susanti; Winkelman, Jozef; Schuur, Boelo; Heeres, Hero; Yue, Jun

    2015-01-01

    Lactic acid is an important biobased chemical and, among others, is used for the production of poly-lactic acid. Down-stream processing using state of the art technology is energy intensive and leads to the formation of large amounts of salts. In this presentation, experimental and modeling studies

  9. Pruning Chinese trees : an experimental and modelling approach

    NARCIS (Netherlands)

    Zeng, Bo

    2001-01-01

    Pruning of trees, in which some branches are removed from the lower crown of a tree, has been extensively used in China in silvicultural management for many purposes. With an experimental and modelling approach, the effects of pruning on tree growth and on the harvest of plant material were studied.

  10. Two-phase flow experimental studies in micro-models

    NARCIS (Netherlands)

    Karadimitriou, N.K.

    2013-01-01

    The aim of this research project was to put more physics into theories of two-phase flow. The significance of including interfacial area as a separate variable in two-phase flow and transport models was investigated. In order to investigate experimentally the significance of the inclusion of

  11. Local linear model tree and Neuro-Fuzzy system for modelling and control of an experimental pH neutralization process

    OpenAIRE

    Petchinathan,G.; Valarmathi,K.; Devaraj,D.; Radhakrishnan,T. K.

    2014-01-01

    This paper describes the modelling and control of a pH neutralization process using a Local Linear Model Tree (LOLIMOT) and an adaptive neuro-fuzzy inference system (ANFIS). The Direct and Inverse model building using LOLIMOT and ANFIS structures is described and compared. The direct and inverse models of the pH system are identified based on experimental data for the LOLIMOT and ANFIS structures. The identified models are implemented in the experimental pH system with IMC structure using a G...

  12. Numerical modelling and experimental study of liquid evaporation during gel formation

    Science.gov (United States)

    Pokusaev, B. G.; Khramtsov, D. P.

    2017-11-01

    Gels are promising materials in biotechnology and medicine as a medium for storing cells for bioprinting applications. Gel is a two-phase system consisting of solid medium and liquid phase. Understanding of a gel structure evolution and gel aging during liquid evaporation is a crucial step in developing new additive bioprinting technologies. A numerical and experimental study of liquid evaporation was performed. In experimental study an evaporation process of an agarose gel layer located on Petri dish was observed and mass difference was detected using electronic scales. Numerical model was based on a smoothed particle hydrodynamics method. Gel in a model was represented as a solid-liquid system and liquid evaporation was modelled due to capillary forces and heat transfer. Comparison of experimental data and numerical results demonstrated that model can adequately represent evaporation process in agarose gel.

  13. Integrative structure modeling with the Integrative Modeling Platform.

    Science.gov (United States)

    Webb, Benjamin; Viswanath, Shruthi; Bonomi, Massimiliano; Pellarin, Riccardo; Greenberg, Charles H; Saltzberg, Daniel; Sali, Andrej

    2018-01-01

    Building models of a biological system that are consistent with the myriad data available is one of the key challenges in biology. Modeling the structure and dynamics of macromolecular assemblies, for example, can give insights into how biological systems work, evolved, might be controlled, and even designed. Integrative structure modeling casts the building of structural models as a computational optimization problem, for which information about the assembly is encoded into a scoring function that evaluates candidate models. Here, we describe our open source software suite for integrative structure modeling, Integrative Modeling Platform (https://integrativemodeling.org), and demonstrate its use. © 2017 The Protein Society.

  14. Development of the tube bundle structure for fluid-structure interaction analysis model

    International Nuclear Information System (INIS)

    Yoon, Kyung Ho; Kim, Jae Yong

    2010-02-01

    Tube bundle structures within a Boiler or heat exchanger are laid the fluid-structure, thermal-structure and fluid-thermal-structure coupled boundary condition. In these complicated boundary conditions, Fluid-structure interaction (FSI) occurs when fluid flow causes deformation of the structure. This deformation, in turn, changes the boundary conditions for the fluid flow. The structural analysis discipline, and then independently analyzed each other. However, the fluid dynamic force effect the behavior of the structure, and the vibration amplitude of the structure to fluid. FSI analysis model was separately created fluid and structure model, and then defined the fsi boundary condition, and simultaneously analyzed in one domain. The analysis results were compared with those of the experimental method for validating the analysis model. Flow-induced vibration test was executed with single rod configuration. The vibration amplitudes of a fuel rod were measured by the laser vibro-meter system in x and y-direction. The analyses results were not closely with the test data, but the trend was very similar with the test result. In fsi coupled analysis case, the turbulent model was very important with the reliability of the accuracy of the analysis model. Therefore, the analysis model will be needed to further study

  15. Numerical and experimental simulation of the mechanical behaviour of inflatable structures

    Science.gov (United States)

    Siguier, J.-M.; Vialettes, P.; Guigue, P.; Karama, M.; Mistou, S.; Dalverny, O.; Granier, S.; Petitjean, F.

    2003-09-01

    Inflatable structures are a great challenge for future space applications. Whatever the technical solutions adopted, a number of significant technological problems have to be solved. An important point is the mechanical behavior of the structure during the deployment and before the stiffening process. With our experience in stratospheric ballooning, we have been developing a facility, called NIRVANA, to characterize the mechanical behavior of pressurized structures in space or stratospheric environment. That is, vacuum or low absolute pressure, controlled internal or differential pressure, and low temperatures (down to -120°C). Sample under test can be either part of a pressurized structure fixed between the two parts of the facility or a complete pressurized system if the volume is less than 1 m3. The facility is equipped with a stereoscopic CCD camera device which measures the 3D strain or displacement of the structure under test. To illustrate the possibilities of this facility, we show results obtained with an envelope element of a superpressure stratospheric balloon. This envelope is made with polymer films assembled with an thermo-reactivated adhesive tape. The sample, of 1.5m diameter, is submitted to differential pressure steps while 3D displacements are measured. Experimental results are compared to numerical ones obtained by a finite element code implemented with mechanical behavior law of polymeric materials. The modelization gives results which largely agree with the experiment and enable us to continue with cold conditions and more complex structures.

  16. Structural Characterization of an Historical Building by Means of Experimental Tests on Full-Scale Elements

    Directory of Open Access Journals (Sweden)

    Marco Bovo

    2017-01-01

    Full Text Available In order to properly design strengthening intervention of existing buildings, careful assessment of the structural behavior is certainly required. This is particularly important when dealing with historical constructions made of heterogeneous materials like masonry or stonework. In this context, this paper presents the results of knowledge process on a large monumental nineteenth century building located in Trieste. The traditional investigation approach considering a wide number of destructive tests for characterization of materials and evaluation of the structural details were not admissible due to the valuable cultural and historical importance of the building. Therefore, an alternative and not conventional investigation approach has been considered. After a wide historical research and a detailed structural survey, it has been possible to identify the main structural systems of the building. Then, to characterize the structural response, a limited number of nondestructive tests but on full-scale typological systems have been preferred to a larger number of destructive tests on specimens of the different materials. The selected experimental load tests have been conducted in order to assess the actual structural response of the main systems that constitute the building, thus allowing for a fine tuning of both the rehabilitation interventions and the numerical finite element models.

  17. Systematic integration of experimental data and models in systems biology.

    Science.gov (United States)

    Li, Peter; Dada, Joseph O; Jameson, Daniel; Spasic, Irena; Swainston, Neil; Carroll, Kathleen; Dunn, Warwick; Khan, Farid; Malys, Naglis; Messiha, Hanan L; Simeonidis, Evangelos; Weichart, Dieter; Winder, Catherine; Wishart, Jill; Broomhead, David S; Goble, Carole A; Gaskell, Simon J; Kell, Douglas B; Westerhoff, Hans V; Mendes, Pedro; Paton, Norman W

    2010-11-29

    The behaviour of biological systems can be deduced from their mathematical models. However, multiple sources of data in diverse forms are required in the construction of a model in order to define its components and their biochemical reactions, and corresponding parameters. Automating the assembly and use of systems biology models is dependent upon data integration processes involving the interoperation of data and analytical resources. Taverna workflows have been developed for the automated assembly of quantitative parameterised metabolic networks in the Systems Biology Markup Language (SBML). A SBML model is built in a systematic fashion by the workflows which starts with the construction of a qualitative network using data from a MIRIAM-compliant genome-scale model of yeast metabolism. This is followed by parameterisation of the SBML model with experimental data from two repositories, the SABIO-RK enzyme kinetics database and a database of quantitative experimental results. The models are then calibrated and simulated in workflows that call out to COPASIWS, the web service interface to the COPASI software application for analysing biochemical networks. These systems biology workflows were evaluated for their ability to construct a parameterised model of yeast glycolysis. Distributed information about metabolic reactions that have been described to MIRIAM standards enables the automated assembly of quantitative systems biology models of metabolic networks based on user-defined criteria. Such data integration processes can be implemented as Taverna workflows to provide a rapid overview of the components and their relationships within a biochemical system.

  18. Waste glass corrosion modeling: Comparison with experimental results

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1994-01-01

    Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations

  19. A resource for benchmarking the usefulness of protein structure models.

    Science.gov (United States)

    Carbajo, Daniel; Tramontano, Anna

    2012-08-02

    Increasingly, biologists and biochemists use computational tools to design experiments to probe the function of proteins and/or to engineer them for a variety of different purposes. The most effective strategies rely on the knowledge of the three-dimensional structure of the protein of interest. However it is often the case that an experimental structure is not available and that models of different quality are used instead. On the other hand, the relationship between the quality of a model and its appropriate use is not easy to derive in general, and so far it has been analyzed in detail only for specific application. This paper describes a database and related software tools that allow testing of a given structure based method on models of a protein representing different levels of accuracy. The comparison of the results of a computational experiment on the experimental structure and on a set of its decoy models will allow developers and users to assess which is the specific threshold of accuracy required to perform the task effectively. The ModelDB server automatically builds decoy models of different accuracy for a given protein of known structure and provides a set of useful tools for their analysis. Pre-computed data for a non-redundant set of deposited protein structures are available for analysis and download in the ModelDB database. IMPLEMENTATION, AVAILABILITY AND REQUIREMENTS: Project name: A resource for benchmarking the usefulness of protein structure models. Project home page: http://bl210.caspur.it/MODEL-DB/MODEL-DB_web/MODindex.php.Operating system(s): Platform independent. Programming language: Perl-BioPerl (program); mySQL, Perl DBI and DBD modules (database); php, JavaScript, Jmol scripting (web server). Other requirements: Java Runtime Environment v1.4 or later, Perl, BioPerl, CPAN modules, HHsearch, Modeller, LGA, NCBI Blast package, DSSP, Speedfill (Surfnet) and PSAIA. License: Free. Any restrictions to use by non-academics: No.

  20. A resource for benchmarking the usefulness of protein structure models.

    KAUST Repository

    Carbajo, Daniel

    2012-08-02

    BACKGROUND: Increasingly, biologists and biochemists use computational tools to design experiments to probe the function of proteins and/or to engineer them for a variety of different purposes. The most effective strategies rely on the knowledge of the three-dimensional structure of the protein of interest. However it is often the case that an experimental structure is not available and that models of different quality are used instead. On the other hand, the relationship between the quality of a model and its appropriate use is not easy to derive in general, and so far it has been analyzed in detail only for specific application. RESULTS: This paper describes a database and related software tools that allow testing of a given structure based method on models of a protein representing different levels of accuracy. The comparison of the results of a computational experiment on the experimental structure and on a set of its decoy models will allow developers and users to assess which is the specific threshold of accuracy required to perform the task effectively. CONCLUSIONS: The ModelDB server automatically builds decoy models of different accuracy for a given protein of known structure and provides a set of useful tools for their analysis. Pre-computed data for a non-redundant set of deposited protein structures are available for analysis and download in the ModelDB database. IMPLEMENTATION, AVAILABILITY AND REQUIREMENTS: Project name: A resource for benchmarking the usefulness of protein structure models. Project home page: http://bl210.caspur.it/MODEL-DB/MODEL-DB_web/MODindex.php.Operating system(s): Platform independent. Programming language: Perl-BioPerl (program); mySQL, Perl DBI and DBD modules (database); php, JavaScript, Jmol scripting (web server). Other requirements: Java Runtime Environment v1.4 or later, Perl, BioPerl, CPAN modules, HHsearch, Modeller, LGA, NCBI Blast package, DSSP, Speedfill (Surfnet) and PSAIA. License: Free. Any restrictions to use by

  1. Damping mechanisms and models in structural dynamics

    DEFF Research Database (Denmark)

    Krenk, Steen

    2002-01-01

    Several aspects of damping models for dynamic analysis of structures are investigated. First the causality condition for structural response is used to identify rules for the use of complex-valued frequency dependent material models, illustrated by the shortcomings of the elastic hysteretic model...

  2. Relating structure and dynamics in organisation models

    NARCIS (Netherlands)

    Jonkers, C.M.; Treur, J.

    2002-01-01

    To understand how an organisational structure relates to dynamics is an interesting fundamental challenge in the area of social modelling. Specifications of organisational structure usually have a diagrammatic form that abstracts from more detailed dynamics. Dynamic properties of agent systems,

  3. Experimental and theoretical studies on concrete structures with special-shaped shear walls

    Directory of Open Access Journals (Sweden)

    LIU Jianxin

    2014-06-01

    Full Text Available On the basis of concept design and staggered shear panels structure,this paper puts forward a new reinforced concrete high rise biuding structure with special-shaped shear walls and presents an experimental study of the seismic performance of the new special-shaped shear walls structure under low reversed cyclic loading using MTS electro hydraulic servo system.Compared with experimental results,a finite element analysis on this special-shaped shear wall structure,which considers the nonlinearity of concrete structure,is found suitable.It shows that the experimental results fairly confirms to the calculated values,which indicates that this new structure has advantages as good architecture function,big effective space,high overall lateral stiffness,fine ductility,advanced seismic behavior,etc..That is,the close r agreement between the theoretical and experimental results indicates the proposed shear wall structure has wide applications.

  4. CCDC 713130: Experimental Crystal Structure Determination : bis(2,5-Dihydrobenzylammonium) hexachloro-osmium(iv)

    KAUST Repository

    Reiner, T.

    2011-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 1515632: Experimental Crystal Structure Determination : hexakis(dimethyl sulfoxide)-manganese(ii) tetraiodide

    KAUST Repository

    Haque, M.A.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. CCDC 844303: Experimental Crystal Structure Determination : 1,1,3,3-Tetraphenyldiphosphoxane 1,3-disulfide

    KAUST Repository

    Al-Masri, H.T.

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. CCDC 721713: Experimental Crystal Structure Determination : Dichloro-(ethyl phenylalaninate)-tris(pyridine)-ruthenium(ii)

    KAUST Repository

    Reiner, Thomas

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  8. CCDC 930139: Experimental Crystal Structure Determination : Chloro-(1-cyclododecyl-3-mesitylimidazol-2-ylidene)-silver

    KAUST Repository

    Queval, Pierre

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. CCDC 1419754: Experimental Crystal Structure Determination : octakis(mu2-2-phenylethanethiolato)-tetra-nickel

    KAUST Repository

    Joya, Khurram S.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. CCDC 1419731: Experimental Crystal Structure Determination : dodecakis(mu-2-phenylethanethiolato)-hexa-nickel dichloromethane solvate

    KAUST Repository

    Joya, Khurram S.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. CCDC 1477678: Experimental Crystal Structure Determination : (1,3-dimesitylimidazolidin-2-ylidene)-trimethyl-gallium

    KAUST Repository

    Wu, Melissa M.

    2017-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  12. CCDC 1477679: Experimental Crystal Structure Determination : (1,3-dimesitylimidazolidin-2-ylidene)-trimethyl-indium

    KAUST Repository

    Wu, Melissa M.

    2017-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 1024814: Experimental Crystal Structure Determination : 1,3-Dimesitylimidazolidine-2-selenone

    KAUST Repository

    Vummaleti, Sai V. C.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. CCDC 1015953: Experimental Crystal Structure Determination : 1,3,6,8-tetrakis(4-phenoxyphenyl)pyrene

    KAUST Repository

    El-Assaad, Tarek H.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 1011330: Experimental Crystal Structure Determination : 1,3,6,8-tetrakis(4-fluorophenyl)pyrene

    KAUST Repository

    El-Assaad, Tarek H.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. CCDC 1436716: Experimental Crystal Structure Determination : 5-fluoro-4-iodo-2,1,3-benzothiadiazole

    KAUST Repository

    Shi, Qinqin

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  17. CCDC 1436717: Experimental Crystal Structure Determination : 2-bromo-4,5-diiodo-1,3-thiazole

    KAUST Repository

    Shi, Qinqin

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. CCDC 1010350: Experimental Crystal Structure Determination : dichloro-(methylenebis(di-t-butylphosphine))-palladium(ii)

    KAUST Repository

    Roesle, Philipp

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  19. CCDC 1446070: Experimental Crystal Structure Determination : tris(Pentafluorophenyl)-(triethylsilyl formate)-boron

    KAUST Repository

    Chen, Jiawei

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. CCDC 713129: Experimental Crystal Structure Determination : (eta^6^-Benzylammonium)-dichloro-(dimethylsulfoxide-S)-ruthenium(ii) chloride

    KAUST Repository

    Reiner, T.

    2011-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  1. CCDC 721712: Experimental Crystal Structure Determination : (N-(2-Aminoethyl)-4-methylbenzenesulfonamidato)-(phenylalaninato)-ruthenium dimethylsulfoxide solvate

    KAUST Repository

    Reiner, Thomas

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  2. CCDC 844302: Experimental Crystal Structure Determination : N-1-Naphthyl-P,P-diphenylphosphinoselenoic amide

    KAUST Repository

    Al-Masri, H.T.

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. CCDC 1475929: Experimental Crystal Structure Determination : trimethylammonium tribromo-tin(iv)

    KAUST Repository

    Dang, Yangyang

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  4. CCDC 1475931: Experimental Crystal Structure Determination : trimethylammonium trichloro-tin(iv)

    KAUST Repository

    Dang, Yangyang

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 887968: Experimental Crystal Structure Determination : Dichloro-bis(tricyclohexylphosphine)-(3-phenylindenylidene)-ruthenium tetrahydrofuran solvate

    KAUST Repository

    Urbina-Blanco, C.A.

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. CCDC 933273: Experimental Crystal Structure Determination : Chloro-(1-cyclododecyl-3-mesitylimidazol-2-ylidene)-gold

    KAUST Repository

    Queval, Pierre

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. CCDC 1059905: Experimental Crystal Structure Determination : 7,13-dimesitylindeno[1,2-b]thioxanthene

    KAUST Repository

    Shi, Xueliang

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  8. CCDC 951636: Experimental Crystal Structure Determination : bis(tetra-n-butylammonium) trichloro-(nitrosyl)-(oxalato)-ruthenium

    KAUST Repository

    Kuhn, Paul-Steffen

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. CCDC 1427126: Experimental Crystal Structure Determination : bis(1,10-Phenanthroline)-copper pentafluoropropanoate

    KAUST Repository

    Huang, Yangjie

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. CCDC 1446069: Experimental Crystal Structure Determination : tris(Pentafluorophenyl)-(triethylsilyl formate)-aluminium

    KAUST Repository

    Chen, Jiawei

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. CCDC 1420582: Experimental Crystal Structure Determination : catena-[(mu-4,4'-sulfonyldibenzoato)-calcium ethane

    KAUST Repository

    Plonka, Anna M.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  12. CCDC 1420581: Experimental Crystal Structure Determination : catena-[(mu-4,4'-sulfonyldibenzoato)-calcium ethylene

    KAUST Repository

    Plonka, Anna M.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 1429311: Experimental Crystal Structure Determination : N-(5-Bromoquinolin-8-yl)benzamide

    KAUST Repository

    Xu, Jun

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. CCDC 1482638: Experimental Crystal Structure Determination : trimethylammonium trichloro-tin(iv)

    KAUST Repository

    Dang, Yangyang

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 1420580: Experimental Crystal Structure Determination : catena-[(mu-4,4'-sulfonyldibenzoato)-calcium acetylene

    KAUST Repository

    Plonka, Anna M.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. CCDC 1475930: Experimental Crystal Structure Determination : trimethylammonium trichloro-tin(iv)

    KAUST Repository

    Dang, Yangyang

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  17. CCDC 1427127: Experimental Crystal Structure Determination : bis(1,10-Phenanthroline)-copper heptafluorobutanoate benzene solvate

    KAUST Repository

    Huang, Yangjie

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. CCDC 1048729: Experimental Crystal Structure Determination : bis(2-(hydroxyimino)-3-phenylpropanoato)-tin(ii)

    KAUST Repository

    Khanderi, Jayaprakash

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  19. CCDC 1048727: Experimental Crystal Structure Determination : bis(2-(hydroxyimino)propanoato)-tin(ii)

    KAUST Repository

    Khanderi, Jayaprakash

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. CCDC 1048728: Experimental Crystal Structure Determination : ammonium tris(2-(methoxyimino)propanoato)-tin(ii) dihydrate

    KAUST Repository

    Khanderi, Jayaprakash

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  1. CCDC 870534: Experimental Crystal Structure Determination : Dichloro-trimethyl-tantalum(v)

    KAUST Repository

    Chen, Yin

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  2. CCDC 963856: Experimental Crystal Structure Determination : catena-[bis(mu2-2-methylimidazole)-zinc

    KAUST Repository

    Shekhah, Osama

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. Heterogeneity in Pure Microbial Systems: Experimental Measurements and Modeling.

    Science.gov (United States)

    González-Cabaleiro, Rebeca; Mitchell, Anca M; Smith, Wendy; Wipat, Anil; Ofiţeru, Irina D

    2017-01-01

    Cellular heterogeneity influences bioprocess performance in ways that until date are not completely elucidated. In order to account for this phenomenon in the design and operation of bioprocesses, reliable analytical and mathematical descriptions are required. We present an overview of the single cell analysis, and the mathematical modeling frameworks that have potential to be used in bioprocess control and optimization, in particular for microbial processes. In order to be suitable for bioprocess monitoring, experimental methods need to be high throughput and to require relatively short processing time. One such method used successfully under dynamic conditions is flow cytometry. Population balance and individual based models are suitable modeling options, the latter one having in particular a good potential to integrate the various data collected through experimentation. This will be highly beneficial for appropriate process design and scale up as a more rigorous approach may prevent a priori unwanted performance losses. It will also help progressing synthetic biology applications to industrial scale.

  4. Experimentally supported mathematical modeling of continuous baking processes

    DEFF Research Database (Denmark)

    Stenby Andresen, Mette

    and temperature) and control the process (air flow, temperature, and humidity) are therefore emphasized. The oven is furthermore designed to work outside the range of standard tunnel ovens, making it interesting for manufacturers of both baking products and baking equipment. A mathematical model describing......The scope of the PhD project was to increase knowledge on the process-to-product interactions in continuous tunnel ovens. The work has focused on five main objectives. These objectives cover development of new experimental equipment for pilot plant baking experiments, mathematical modeling of heat...... on mass transfer was examined through comparison of different modeling set-ups and experimental data. It was found that while the baking tray is likely to reduce the evaporation from the bottom surface, it is not correct to assume that no evaporation takes place at the covered surface. Parallel...

  5. Experimental, statistical, and biological models of radon carcinogenesis

    International Nuclear Information System (INIS)

    Cross, F.T.

    1991-09-01

    Risk models developed for underground miners have not been consistently validated in studies of populations exposed to indoor radon. Imprecision in risk estimates results principally from differences between exposures in mines as compared to domestic environments and from uncertainties about the interaction between cigarette-smoking and exposure to radon decay products. Uncertainties in extrapolating miner data to domestic exposures can be reduced by means of a broad-based health effects research program that addresses the interrelated issues of exposure, respiratory tract dose, carcinogenesis (molecular/cellular and animal studies, plus developing biological and statistical models), and the relationship of radon to smoking and other copollutant exposures. This article reviews experimental animal data on radon carcinogenesis observed primarily in rats at Pacific Northwest Laboratory. Recent experimental and mechanistic carcinogenesis models of exposures to radon, uranium ore dust, and cigarette smoke are presented with statistical analyses of animal data. 20 refs., 1 fig

  6. Experimental validation of the multiphase extended Leblond's model

    Science.gov (United States)

    Weisz-Patrault, Daniel

    2017-10-01

    Transformation induced plasticity is a crucial contribution of the simulation of several forming processes involving phase transitions under mechanical loads, resulting in large irreversible strain even though the applied stress is under the yield stress. One of the most elegant and widely used models is based on analytic homogenization procedures and has been proposed by Leblond et al. [1-4]. Very recently, a simple extension of the Leblond's model has been developed by Weisz-Patrault [8]. Several product phases are taken into account and several assumptions are relaxed in order to extend the applicability of the model. The present contribution compares experimental tests with numerical computations, in order to discuss the validity of the developed theory. Thus, experimental results extracted from the existing literature are analyzed. Results show a good agreement between measurements and theoretical computations.

  7. Experimental assessment and modelling of nitrate utilisation for primary sludge.

    Science.gov (United States)

    Avcioğlu, E; Sözen, S; Orhon, D; van Loosdrecht, M C M

    2002-01-01

    Electron acceptor utilisation potential of filtered primary sludge under anoxic conditions was experimentally investigated. Major kinetic and stoichiometric parameters were assessed by means of model evaluation of nitrate profile obtained in batch reactors. ASM1, modified for endogenous decay, and ASM3 were used for model simulation. Both models provided consistent interpretation of experimental data. ASM1 yielded mu(H) and Y(HD) values of 6.1 d(-1) and 0.64 g cell COD(g COD)(-1) respectively for heterotrophic anoxic growth. The corresponding storage mechanism associated with ASM3 could be characterised by a k(STO) of 13 g COD (g COD d)(-1) and a Y(STO) of 0.78 g COD(g COD)(-1). The high k(STO) value suggests re-evaluation of the concept of readily biodegradable substrate as defined in ASM3 and tested in the study.

  8. Experimental, statistical and biological models of radon carcinogenesis

    International Nuclear Information System (INIS)

    Cross, F.T.

    1992-01-01

    Risk models developed for underground miners have not been consistently validated in studies of populations exposed to indoor radon. Imprecision in risk estimates results principally from differences between exposures in mines as compared with domestic environments and from uncertainties about the interaction between cigarette smoking and exposure to radon decay products. Uncertainties in extrapolating miner data to domestic exposures can be reduced by means of a broad-based health effects research programme that addresses the interrelated issues of exposure, respiratory tract dose, carcinogenesis (molecular/cellular and animal studies, plus developing biological and statistical models) and the relationship of radon to smoking and other co-pollutant exposures. This article reviews experimental animal data on radon carcinogenesis observed primarily in rats at Pacific Northwest Laboratory. Recent experimental and mechanistic carcinogenesis models of exposures to radon, uranium ore dust, and cigarette smoke are presented with statistical analyses of animal data. (author)

  9. Physics of human cooperation: experimental evidence and theoretical models

    Science.gov (United States)

    Sánchez, Angel

    2018-02-01

    In recent years, many physicists have used evolutionary game theory combined with a complex systems perspective in an attempt to understand social phenomena and challenges. Prominent among such phenomena is the issue of the emergence and sustainability of cooperation in a networked world of selfish or self-focused individuals. The vast majority of research done by physicists on these questions is theoretical, and is almost always posed in terms of agent-based models. Unfortunately, more often than not such models ignore a number of facts that are well established experimentally, and are thus rendered irrelevant to actual social applications. I here summarize some of the facts that any realistic model should incorporate and take into account, discuss important aspects underlying the relation between theory and experiments, and discuss future directions for research based on the available experimental knowledge.

  10. Regression Model Optimization for the Analysis of Experimental Data

    Science.gov (United States)

    Ulbrich, N.

    2009-01-01

    A candidate math model search algorithm was developed at Ames Research Center that determines a recommended math model for the multivariate regression analysis of experimental data. The search algorithm is applicable to classical regression analysis problems as well as wind tunnel strain gage balance calibration analysis applications. The algorithm compares the predictive capability of different regression models using the standard deviation of the PRESS residuals of the responses as a search metric. This search metric is minimized during the search. Singular value decomposition is used during the search to reject math models that lead to a singular solution of the regression analysis problem. Two threshold dependent constraints are also applied. The first constraint rejects math models with insignificant terms. The second constraint rejects math models with near-linear dependencies between terms. The math term hierarchy rule may also be applied as an optional constraint during or after the candidate math model search. The final term selection of the recommended math model depends on the regressor and response values of the data set, the user s function class combination choice, the user s constraint selections, and the result of the search metric minimization. A frequently used regression analysis example from the literature is used to illustrate the application of the search algorithm to experimental data.

  11. Lateral-torsional buckling of laminated structural glass beams. Experimental study

    OpenAIRE

    Pešek, Ondřej; Melcher, Jindřich

    2017-01-01

    This paper deals with experimental research of stability behaviour of laminated structural glass beams. The purpose of the research is the evaluation of lateral-torsional buckling resistance and actual behaviour of the beams due to absence of standards for design of glass load-bearing structures. The experimental research follows the previous one focusing on measuring of initial geometrical imperfections of glass members and experimental evaluation of flexural buckling resistance of structura...

  12. Structure-property relationships in model polyolefins

    Science.gov (United States)

    Weimann, Peter Andrew

    Correlations between structure and properties were examined in a variety of model polyolefin blend and block copolymer systems. Anionic polymerization and catalytic hydrogenation were used to prepare the polymers, followed by characterization of structure and the properties of interest. Production of poly(vinylcyclohexane) (PVCH) through hydrogenation of poly(styrene), using a novel Pt/SiOsb2 catalyst, was examined in some detail. Kinetics were established through time sampling of reactions performed under a variety of conditions, followed by characterization of the extent of saturation. The Pt/SiOsb2 catalyst was quantitatively demonstrated to be more efficient than other heterogeneous hydrogenation catalysts for saturation of poly(styrene). Relationships between chain structure and miscibility were explored in blends of isotactic poly(propylene) (i-PP) with a series of model saturated polyolefins. An experimental correlation between conformational symmetry and miscibility in polyolefin blends guided synthesis of several model poly(ethylene/ethylethylene) random copolymers. Using small-angle neutron scattering, melt miscibility was demonstrated for "conformationally symmetric" blends of poly(ethylene/ethylethylene) random copolymers and i-PP, while "conformationally asymmetric" random copolymers phase separated from i-PP. Phase separated poly(ethylene) (PE) - PVCH block copolymers were employed in a study of crystallization of tethered PE chains in confined environments. In these materials, the glassy PVCH forced the PE to crystallize in geometries with well-defined spacing and connectivity. Effects of chain tethering were studied through comparison of "EV" diblocks to "VEV" triblocks. Increasing confinement, reflected by decreasing the domain spacing of the block copolymer, led to a reduction in crystallite size. The geometry and connectivity of the PE component also had a major influence on crystallization. Crystal growth was retarded in block copolymers where

  13. Development of experimental alloxan model of diabetes mellitus

    Directory of Open Access Journals (Sweden)

    V.V. Semenko

    2017-05-01

    Full Text Available Background. One of the main causes that lead to the disability of diabetic patients is diabetic retinopathy (DR. The relevance of the problem of DR necessitates the development of optimal experimental models on experimental animals to find effective ways of correcting this pathology. The purpose of our work was to develop an experimental alloxan model of type 1 diabetes mellitus (DM for the study of DR, which would not result in the lethal outcome of experimental animals under the action of alloxan; histological examination of changes in the tissues of the eyeball in the reproduction of the DM model for the selection of new effective methods for the metabolic treatment of DR in the early stages. Materials and methods. The experiment was carried out on white outbred Wistar rats weighing 180–200 g. The first group consisted of 20 animals that were not subjected to any influence, served as a control; second group — 30 animals, in which DM was modeled by administration of alloxan and fructose. Results. When modeling DR, vessel changes in the form of wall fibrosis, edema of the endothelium and vasospasm were found. There was also a decrease in the amount of pigment granules, dystrophic changes in the cells of the ganglionic layer and a layer of retinal rods and cones, which coincides with the descriptions of damage to the coats of the eyeball in patients with DM. Conclusions. In our studies, we have calculated the optimal dose of alloxan administration, which does not lead to the death of rats (the lethality of rats was absent and is an effective model not only of DM in general, but also of DR.

  14. Functional Coverage of the Human Genome by Existing Structures, Structural Genomics Targets, and Homology Models.

    Directory of Open Access Journals (Sweden)

    2005-08-01

    Full Text Available The bias in protein structure and function space resulting from experimental limitations and targeting of particular functional classes of proteins by structural biologists has long been recognized, but never continuously quantified. Using the Enzyme Commission and the Gene Ontology classifications as a reference frame, and integrating structure data from the Protein Data Bank (PDB, target sequences from the structural genomics projects, structure homology derived from the SUPERFAMILY database, and genome annotations from Ensembl and NCBI, we provide a quantified view, both at the domain and whole-protein levels, of the current and projected coverage of protein structure and function space relative to the human genome. Protein structures currently provide at least one domain that covers 37% of the functional classes identified in the genome; whole structure coverage exists for 25% of the genome. If all the structural genomics targets were solved (twice the current number of structures in the PDB, it is estimated that structures of one domain would cover 69% of the functional classes identified and complete structure coverage would be 44%. Homology models from existing experimental structures extend the 37% coverage to 56% of the genome as single domains and 25% to 31% for complete structures. Coverage from homology models is not evenly distributed by protein family, reflecting differing degrees of sequence and structure divergence within families. While these data provide coverage, conversely, they also systematically highlight functional classes of proteins for which structures should be determined. Current key functional families without structure representation are highlighted here; updated information on the "most wanted list" that should be solved is available on a weekly basis from http://function.rcsb.org:8080/pdb/function_distribution/index.html.

  15. Practical Soil-Shallow Foundation Model for Nonlinear Structural Analysis

    Directory of Open Access Journals (Sweden)

    Moussa Leblouba

    2016-01-01

    Full Text Available Soil-shallow foundation interaction models that are incorporated into most structural analysis programs generally lack accuracy and efficiency or neglect some aspects of foundation behavior. For instance, soil-shallow foundation systems have been observed to show both small and large loops under increasing amplitude load reversals. This paper presents a practical macroelement model for soil-shallow foundation system and its stability under simultaneous horizontal and vertical loads. The model comprises three spring elements: nonlinear horizontal, nonlinear rotational, and linear vertical springs. The proposed macroelement model was verified using experimental test results from large-scale model foundations subjected to small and large cyclic loading cases.

  16. A Two-Surface Viscoplastic Model for the Structural Steel

    Directory of Open Access Journals (Sweden)

    Dong-Keon Kim

    Full Text Available Abstract As extension of the previous two-surface model in plasticity, a two-surface model for viscoplasticity is presented herein. In order to validate and investigate the performance of the proposed model, several numerical simulations are undertaken especially for structural steel under monotonic and cyclic loading cases, where experimental results and numerical results from the rate dependent kinematic hardening model are also provided for the reference. For all the cases studied, the proposed model can appropriately account for the rate-effects in both maximum stress and hysteretic shapes.

  17. Molten carbonate fuel cell: dynamic numerical modeling and experimental investigation

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Elisangela Martins [National Institute for Space Research, Cachoeira Paulista, SP (Brazil). Combustion and Propulsion Lab.], e-mail: elisangela@lcp.inpe.br; Jabbari, Faryar [University of California, Irvine, CA (United States). Mechanical and Aerospace Engineering Dept.], e-mail: fjabbari@uci.edu; Brouwer, Jacob [University of California, Irvine, CA (United States). National Fuel Cell Research Center], e-mail: jb@nfcrc.uci.edu

    2006-07-01

    In this paper, a detailed model incorporating simplified geometric resolution of a molten carbonate fuel cell (MCFC) with detailed and dynamic simulation of all physical, chemical, and electrochemical processes in the stream-wise direction is presented. The model was developed using mass and momentum conservation, electrochemical and chemical reaction mechanisms, and heat transfer. Results from the model are compared with data from an experimental MCFC unit. Furthermore, the model was applied to predict dynamic variations of voltage, current and temperature in an MCFC as it responds to varying load demands. The voltage was evaluated by applying a model developed by Yu h and Selman (1991a, 1991b). The results show that the model can be used to predict voltage and dynamic response characteristics of an MCFC accurately and consistently for a variety of temperatures and pressures. (author)

  18. Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam

    Science.gov (United States)

    Allen, Albert R.; Schiller, Noah H.

    2016-01-01

    Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.

  19. Experimental validation of a Bayesian model of visual acuity.

    LENUS (Irish Health Repository)

    Dalimier, Eugénie

    2009-01-01

    Based on standard procedures used in optometry clinics, we compare measurements of visual acuity for 10 subjects (11 eyes tested) in the presence of natural ocular aberrations and different degrees of induced defocus, with the predictions given by a Bayesian model customized with aberrometric data of the eye. The absolute predictions of the model, without any adjustment, show good agreement with the experimental data, in terms of correlation and absolute error. The efficiency of the model is discussed in comparison with image quality metrics and other customized visual process models. An analysis of the importance and customization of each stage of the model is also given; it stresses the potential high predictive power from precise modeling of ocular and neural transfer functions.

  20. Experimental and Numerical Investigation of Vortical Structures in Lean Premixed Swirl-Stabilized Combustion

    Science.gov (United States)

    Taamallah, Soufien; Chakroun, Nadim; Shanbhogue, Santosh; Kewlani, Gaurav; Ghoniem, Ahmed

    2015-11-01

    A combined experimental and LES investigation is performed to identify the origin of major flow dynamics and vortical structures in a model gas turbine's swirl-stabilized turbulent combustor. Swirling flows in combustion lead to the formation of complex flow dynamics and vortical structures that can interact with flames and influence its stabilization. Our experimental results for non-reacting flow show the existence of large scale precession motion. The precessing vortex core (PVC) dynamics disappears with combustion but only above a threshold of equivalence ratio. In addition, large scale vortices along the inner shear layer (ISL) are observed. These structures interact with the ISL stabilized flame and contribute to its wrinkling. Next, the LES setup is validated against the flow field's low-order statistics and point temperature measurement in relevant areas of the chamber. Finally, we show that LES is capable of predicting the precession motion as well as the ISL vortices in the reacting case: we find that ISL vortices originate from a vortex core that is formed right downstream of the swirler's centerbody. The vortex core has a conical spiral shape resembling a corkscrew that interacts - as it winds out - with the flame when it reaches the ISL.

  1. Analysis of a Model for the Morphological Structure of Renal Arterial Tree: Fractal Structure

    Directory of Open Access Journals (Sweden)

    Aurora Espinoza-Valdez

    2013-01-01

    experimental data measurements of the rat kidneys. The fractal dimension depends on the probability of sprouting angiogenesis in the development of the arterial vascular tree of the kidney, that is, of the distribution of blood vessels in the morphology generated by the analytical model. The fractal dimension might determine whether a suitable renal vascular structure is capable of performing physiological functions under appropriate conditions. The analysis can describe the complex structures of the development vasculature in kidney.

  2. Experimental alteration of artificial and natural impact melt rock from the Chesapeake Bay impact structure

    Science.gov (United States)

    Declercq, J.; Dypvik, H.; Aagaard, Per; Jahren, J.; Ferrell, R.E.; Horton, J. Wright

    2009-01-01

    The alteration or transformation of impact melt rock to clay minerals, particularly smectite, has been recognized in several impact structures (e.g., Ries, Chicxulub, Mj??lnir). We studied the experimental alteration of two natural impact melt rocks from suevite clasts that were recovered from drill cores into the Chesapeake Bay impact structure and two synthetic glasses. These experiments were conducted at hydrothermal temperature (265 ??C) in order to reproduce conditions found in meltbearing deposits in the first thousand years after deposition. The experimental results were compared to geochemical modeling (PHREEQC) of the same alteration and to original mineral assemblages in the natural melt rock samples. In the alteration experiments, clay minerals formed on the surfaces of the melt particles and as fine-grained suspended material. Authigenic expanding clay minerals (saponite and Ca-smectite) and vermiculite/chlorite (clinochlore) were identified in addition to analcime. Ferripyrophyllite was formed in three of four experiments. Comparable minerals were predicted in the PHREEQC modeling. A comparison between the phases formed in our experiments and those in the cores suggests that the natural alteration occurred under hydrothermal conditions similar to those reproduced in the experiment. ?? 2009 The Geological Society of America.

  3. Modelling the Crash Response of Composite Structures

    OpenAIRE

    Johnson, A.; Kohlgrüber, D.

    1997-01-01

    The paper describes recent progress on the materials modelling and numerical simulation of the dynamic crash response of fibre reinforced composite structures. The work is based on the application of explicit finite element analysis codes to composite aircraft structures and structural elements under low velocity impact conditions (up to 15 m/s). Structures studied are designed to absorb crash energy and reduce seat deceleration pulses in aircraft subfloor structures, and consist of an aircra...

  4. Investigation of a model vertical motion liquid damper: comparing numerical simulation and experimental evidence

    Science.gov (United States)

    Papadopoulos, Chris; Tabatabai, Habib; Buechel, Craig

    2005-05-01

    Tuned Liquid Dampers (TLD) are used to limit horizontal vibrations in structures, and offer practical alternatives to Tuned Mass Dampers (TMD). However, to our knowledge, liquid damping systems have not been developed to reduce vertical vibrations. In this work, we develop a model for a Vertical Motion Liquid Damper (VMLD), idealized as a discrete, two degree of freedom system. One degree of freedom represents the 'target' structure that is to be damped, and the other represents the approximate, one-dimensional motion of a liquid in a U-shaped tube. Internal losses due to the fluid oscillation serve to limit and control motions of the target structure. The U-shaped tube has a flexible joint such that one vertical portion and the horizontal portion of the tube remain fixed, and the remaining vertical portion of the tube is affixed to the vibrating structure, allowing the liquid to become excited. The equations of motion are derived using Lagrange's Equations, and are integrated using Runge-Kutta algorithms that are available in Matlab. An experimental model was built in the laboratory, consisting of a mass attached to the end of a cantilevered beam (corresponding to the target structure), and a U-tube made from PVC pipe. The various damping and stiffness parameters of the system were calibrated independently based on experimental data. Measured data from the experimental model show reasonable agreement with numerical simulations.

  5. The rabbit as an experimental model in laryngology

    Directory of Open Access Journals (Sweden)

    Carneiro, Christiano de Giacomo

    2009-06-01

    Full Text Available Introduction: In the research in laryngology we normally use animal models. The animal experimentation may also contribute largely for this evolution, mainly for the easy access compared to human larynxes and for they are more easily controlled. Objective: The objective of this work is to analyze the laryngofissure with vocal cords graft as an experimental surgical technique in male adult rabbits. Method: We studied 46 New Zealand albino rabbits submitted to microsurgery in both vocal cords with autologous unilateral or bilateral graft of fat or fascia. Results: There were 4 losses of 3 animals until the first week of the postoperative period and another after 19 days after surgery. In the subsequent animals there were no infection, hematoma or sutures dehiscence. Conclusion: The study enables the conclusion that the experimental laryngofissure in rabbits is a safe method that may be used for laryngological studies.

  6. Transvaginal ultrasound ovarian diathermy: sheep as an experimental model

    Directory of Open Access Journals (Sweden)

    Pimentel Anita M

    2012-01-01

    Full Text Available Abstract Background Some techniques of transvaginal ovarian drilling have been previously described. Nevertheless a monopolar transvaginal ovarian cauterization, that use the expertise and safety of transvaginal puncture for oocyte captation seems to be an easier and feasible approach. The aim of this study was to develop a minimally invasive ovarian cauterization technique under transvaginal ultrasound control, and to evaluate the safety of the transvaginal ovarian monopolar cauterization, female sheep at reproductive age were used as an experimental model. Findings An experimental study was performed in a university research center. Seventeen female sheep (15 Corriedale e 2 Suffolk in reproductive age were submitted to transvaginal ovarian cauterization with a monopolar Valleylab Force 2 electrocautery. Macroscopic and microscopic lesions were assessed. Ovarian size were 1.31 cm2 ± 0,43 (Corriedale and 3.41 cm2 ± 0,64 (Suffolk. From 30 ovaries from Corriedale sheep punctured, only 3 were cauterized, presenting macroscopic and typical microscopic lesion. In the Suffolk sheep group, only one ovary was cauterized. No lesion could be found in the needle path. Conclusions This is the first experimental animal model described for ovarian cauterization needle guided by transvaginal ultrasound. The sheep does not seem to be the ideal animal model to study this technique. Another animal model, whose ovaries are better identified by transvaginal ultrasound should be sought for this technique, theoretically less invasive, before it could be offered safely to women with polycystic ovary syndrome.

  7. Calcium wave propagation in networks of endothelial cells: model-based theoretical and experimental study.

    Directory of Open Access Journals (Sweden)

    Juexuan Long

    Full Text Available In this paper, we present a combined theoretical and experimental study of the propagation of calcium signals in multicellular structures composed of human endothelial cells. We consider multicellular structures composed of a single chain of cells as well as a chain of cells with a side branch, namely a "T" structure. In the experiments, we investigate the result of applying mechano-stimulation to induce signaling in the form of calcium waves along the chain and the effect of single and dual stimulation of the multicellular structure. The experimental results provide evidence of an effect of architecture on the propagation of calcium waves. Simulations based on a model of calcium-induced calcium release and cell-to-cell diffusion through gap junctions shows that the propagation of calcium waves is dependent upon the competition between intracellular calcium regulation and architecture-dependent intercellular diffusion.

  8. The use of Structural Equation Modelling (SEM) in Capital Structure ...

    African Journals Online (AJOL)

    analytic structural equation modelling (SEM) methodology. The SEM Methodology allows the use of more than one indicator for a latent variable. It also estimates the latent variables and accommodates reciprocal causation and interdependences ...

  9. Effects of Erdosteine on Experimental Acute Pancreatitis Model.

    Science.gov (United States)

    Karapolat, Banu; Karapolat, Sami; Gurleyik, Emin; Yasar, Mehmet

    2017-10-01

    To create acute pancreatitis condition experimentally in rats using cerulein, and to reveal histopathological effects in pancreatic tissue with erdosteine. An experimental study. Department of General Surgery, Duzce University, Turkey, from June to October 2014. Thirty male Wistar albino rats were divided into three groups. No procedures were applied to Group 1. The rats in Group 2 and Group 3 were injected cerulein, to establish an experimental pancreatitis model and the blood amylase and lipase values were examined. The rats in Group 3 were given 10 mg/kg erdosteine. This treatment was continued for another 2 days and the rats were sacrificed. The pancreatic tissues were examined histopathologically for edema, inflammation, acinar necrosis, fat necrosis, and vacuolization. The lipase and amylase values and the histopathological examination of pancreatic tissues evidenced that the experimental acute pancreatitis model was established and edema, inflammation, acinar necrosis, fat necrosis, and vacuolization were observed in the pancreatic tissues. The statistical results suggest that erdosteine can decrease the edema, inflammation, acinar necrosis, fat necrosis and vacuolization scores in the tissues. The severity of acute pancreatitis, induced by cerulein in rats, is reduced with the use of erdosteine.

  10. Experimental animal data and modeling of late somatic effects

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1988-01-01

    This section is restricted to radiation-induced life shortening and cancer and mainly to studies with external radiation. The emphasis will be on the experimental data that are available and the experimental systems that could provide the type of data with which to either formulate or test models. Genetic effects which are of concern are not discussed in this section. Experimental animal radiation studies fall into those that establish general principles and those that demonstrate mechanisms. General principles include the influence of dose, radiation quality, dose rate, fractionation, protraction and such biological factors as age and gender. The influence of these factors are considered as general principles because they are independent, at least qualitatively, of the species studied. For example, if an increase in the LET of the radiation causes an increased effectiveness in cancer induction in a mouse a comparable increase in effectiveness can be expected in humans. Thus, models, whether empirical or mechanistic, formulated from experimental animal data should be generally applicable

  11. Experimental animal data and modeling of late somatic effects

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1988-01-01

    This section is restricted to radiation-induced life shortening and cancer and mainly to studies with external radiation. The emphasis will be on the experimental data that are available and the experimental systems that could provide the type of data with which to either formulate or test models. Genetic effects which are of concern are not discussed in this section. Experimental animal radiation studies fall into those that establish general principles and those that demonstrate mechanisms. General principles include the influence of dose, radiation quality, dose rate, fractionation, protraction and such biological factors as age and gender. The influence of these factors are considered as general principles because they are independent, at least qualitatively, of the species studied. For example, if an increase in the LET of the radiation causes an increased effectiveness in cancer induction in a mouse a comparable increase in effectiveness can be expected in humans. Thus, models, whether empirical or mechanistic, formulated from experimental animal data should be generally applicable.

  12. Modeling of soil-water-structure interaction

    DEFF Research Database (Denmark)

    Tang, Tian

    to dynamic ocean waves. The goal of this research project is to develop numerical soil models for computing realistic seabed response in the interacting offshore environment, where ocean waves, seabed and offshore structure highly interact with each other. The seabed soil models developed are based...... as the developed nonlinear soil displacements and stresses under monotonic and cyclic loading. With the FVM nonlinear coupled soil models as a basis, multiphysics modeling of wave-seabed-structure interaction is carried out. The computations are done in an open source code environment, OpenFOAM, where FVM models...... of Computational Fluid Dynamics (CFD) and structural mechanics are available. The interaction in the system is modeled in a 1-way manner: First detailed free surface CFD calculations are executed to obtain a realistic wave field around a given structure. Then the dynamic structural response, due to the motions...

  13. Experimental analysis on stress wave in inhomogeneous multi-layered structures

    International Nuclear Information System (INIS)

    Cho, Yun Ho; Ham, Hyo Sick

    1998-01-01

    The guided wave propagation in inhomogeneous multi-layered structures is experimentally explored based on theoretical dispersion curves. It turns out that proper selection of incident angle and frequency is critical for guided wave generation in multi-layered structures. Theoretical dispersion curves greatly depend on adhesive zone thickness, layer thickness and material properties. It was possible to determine the adhesive zone thickness of an inhomogeneous multi-layered structure by monitoring experimentally the change of dispersion curves.

  14. Experimental validation of the interaction between combustion and structural vibration.

    NARCIS (Netherlands)

    Huls, R.A.; de Boer, Andries; Kok, Jacobus B.W.; van der Hoogt, Peter

    2005-01-01

    To decrease NOx emissions from combustion systems, lean premixed combustion is used. A disadvantage is the increase in sound pressure levels in the combustor, resulting in an increased excitation of the surrounding structure: the liner. This causes fatigue, which limits the life time of the

  15. MRI monitoring of experimental cerebral ischaemia: comparison of two models

    International Nuclear Information System (INIS)

    Forsting, M.; Reith, W.; Doerfler, A.; Meyding-Lamade, U.; Sartor, K.

    1994-01-01

    The aim of this study was to compare two minimally invasive rat models of focal ischaemic stroke as to their ability to simulate clinical stroke reproducibly. In one model a focal infarct was induced using the photochemical Rose Bengal technique. The second model was based on transvascular occlusion of the middle cerebral artery using a cervical approach. In all animals we performed MRI at different times with two different paramagnetic contrast agents. The time course of blood-brain-barrier disruption in the Rose Bengal model differed entirely from that in human brain ischaemia. The experimental stroke showed marked contrast enhancement in the first hour after the onset of ischaemia. On the other hand, the MRI changes in the suture occlusion model were very similar to the changes observed in human brain ischaemia: no early disruption of the blood-brain-barrier and increased T2-signal 4-6 h after the onset of stroke. (orig.)

  16. Validation of the newborn larynx modeling with aerodynamical experimental data.

    Science.gov (United States)

    Nicollas, R; Giordano, J; Garrel, R; Medale, M; Caminat, P; Giovanni, A; Ouaknine, M; Triglia, J M

    2009-06-01

    Many authors have studied adult's larynx modelization, but the mechanisms of newborn's voice production have very rarely been investigated. After validating a numerical model with acoustic data, studies were performed on larynges of human fetuses in order to validate this model with aerodynamical experiments. Anatomical measurements were performed and a simplified numerical model was built using Fluent((R)) with the vocal folds in phonatory position. The results obtained are in good agreement with those obtained by laser Doppler velocimetry (LDV) and high-frame rate particle image velocimetry (HFR-PIV), on an experimental bench with excised human fetus larynges. It appears that computing with first cry physiological parameters leads to a model which is close to those obtained in experiments with real organs.

  17. Microbial community structure in autotrophic nitrifying granules characterized by experimental and simulation analyses

    DEFF Research Database (Denmark)

    Matsumoto, S.; Katoku, M.; Saeki, G.

    2010-01-01

    the bacterial distribution obtained by fluorescence in situ hybridization analysis, as well as the measured oxygen, nitrite, nitrate and ammonium concentration profiles. Results of this study are important because they show that a combination of simulation and experimental techniques can better explain......This study evaluates the community structure in nitrifying granules (average diameter of 1600 mu m) produced in an aerobic reactor fed with ammonia as the sole energy source by a multivalent approach combining molecular techniques, microelectrode measurements and mathematical modelling...... the observed granule development as a result of the multiple bacteria-substrate interactions. The interaction between nitrifying and heterotrophic bacteria was evaluated by assuming three types of heterotrophic bacterial growth on soluble microbial products from nitrifying bacteria. The models described well...

  18. Peltier cells as temperature control elements: Experimental characterization and modeling

    International Nuclear Information System (INIS)

    Mannella, Gianluca A.; La Carrubba, Vincenzo; Brucato, Valerio

    2014-01-01

    The use of Peltier cells to realize compact and precise temperature controlled devices is under continuous extension in recent years. In order to support the design of temperature control systems, a simplified modeling of heat transfer dynamics for thermoelectric devices is presented. By following a macroscopic approach, the heat flux removed at the cold side of Peltier cell can be expressed as Q . c =γ(T c −T c eq ), where γ is a coefficient dependent on the electric current, T c and T c eq are the actual and steady state cold side temperature, respectively. On the other hand, a microscopic modeling approach was pursued via finite element analysis software packages. To validate the models, an experimental apparatus was designed and build-up, consisting in a sample vial with the surfaces in direct contact with Peltier cells. Both modeling approaches led to reliable prediction of transient and steady state sample temperature. -- Highlights: • Simplified modeling of heat transfer dynamics in Peltier cells. • Coupled macroscopic and microscopic approach. • Experimental apparatus: temperature control of a sample vial. • Both modeling approaches predict accurately the transient and steady state sample temperature

  19. Target Soil Impact Verification: Experimental Testing and Kayenta Constitutive Modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Broome, Scott Thomas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Flint, Gregory Mark [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Dewers, Thomas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Newell, Pania [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    This report details experimental testing and constitutive modeling of sandy soil deformation under quasi - static conditions. This is driven by the need to understand constitutive response of soil to target/component behavior upon impact . An experimental and constitutive modeling program was followed to determine elastic - plastic properties and a compressional failure envelope of dry soil . One hydrostatic, one unconfined compressive stress (UCS), nine axisymmetric compression (ACS) , and one uniaxial strain (US) test were conducted at room temperature . Elastic moduli, assuming isotropy, are determined from unload/reload loops and final unloading for all tests pre - failure and increase monotonically with mean stress. Very little modulus degradation was discernable from elastic results even when exposed to mean stresses above 200 MPa . The failure envelope and initial yield surface were determined from peak stresses and observed onset of plastic yielding from all test results. Soil elasto - plastic behavior is described using the Brannon et al. (2009) Kayenta constitutive model. As a validation exercise, the ACS - parameterized Kayenta model is used to predict response of the soil material under uniaxial strain loading. The resulting parameterized and validated Kayenta model is of high quality and suitable for modeling sandy soil deformation under a range of conditions, including that for impact prediction.

  20. WWER reactor fuel performance, modelling and experimental support. Proceedings

    International Nuclear Information System (INIS)

    Stefanova, S.; Chantoin, P.; Kolev, I.

    1994-01-01

    This publication is a compilation of 36 papers presented at the International Seminar on WWER Reactor Fuel Performance, Modelling and Experimental Support, organised by the Institute for Nuclear Research and Nuclear Energy (BG), in cooperation with the International Atomic Energy Agency. The Seminar was attended by 76 participants from 16 countries, including representatives of all major Russian plants and institutions responsible for WWER reactor fuel manufacturing, design and research. The reports are grouped in four chapters: 1) WWER Fuel Performance and Economics: Status and Improvement Prospects: 2) WWER Fuel Behaviour Modelling and Experimental Support; 3) Licensing of WWER Fuel and Fuel Analysis Codes; 4) Spent Fuel of WWER Plants. The reports from the corresponding four panel discussion sessions are also included. All individual papers are recorded in INIS as separate items

  1. Advances in theoretical and experimental XAFS studies of thermodynamic properties, anharmonic effects and structural determination of fcc crystals

    Science.gov (United States)

    Hung, Nguyen Van; Thang, Cu Sy; Duc, Nguyen Ba; Vuong, Dinh Quoc; Tien, Tong Sy

    2017-12-01

    Thermodynamic properties, anharmonic effects and structural determination of fcc crystals have been studied based on the theoretical and experimental Debye-Waller factors presented in terms of cumulant expansion up to the third order, thermal expansion coefficient, X-ray absorption fine structure (XAFS) spectra and their Fourier transform magnitudes. The advances in these studies are performed by the further development of the anharmonic correlated Einstein model primary only for approximating three first XAFS cumulants into the method using that all the considered theoretical and experimental XAFS parameters have been provided based on only the calculated and measured second cumulants. The obtained cumulants describe the anharmonic effects in XAFS contributing to the accurate structural determination. Numerical results for Cu are found to be in good agreement with the experimental values extracted by using the present advanced method and with those obtained by the other measurements.

  2. Mathematical Modeling: A Structured Process

    Science.gov (United States)

    Anhalt, Cynthia Oropesa; Cortez, Ricardo

    2015-01-01

    Mathematical modeling, in which students use mathematics to explain or interpret physical, social, or scientific phenomena, is an essential component of the high school curriculum. The Common Core State Standards for Mathematics (CCSSM) classify modeling as a K-12 standard for mathematical practice and as a conceptual category for high school…

  3. Experimental Models of Transfusion-Related Acute Lung Injury (TRALI)

    OpenAIRE

    Gilliss, Brian M.; Looney, Mark R.

    2011-01-01

    Transfusion-related acute lung injury (TRALI) is defined clinically as acute lung injury occurring within six hours of the transfusion of any blood product. It is the leading cause of transfusion-related death in the United States, but under-recognition and diagnostic uncertainty have limited clinical research to smaller case control studies. In this review we will discuss the contribution of experimental models to the understanding of TRALI pathophysiology and potential therapeutic approache...

  4. On the model-free control of an experimental greenhouse

    OpenAIRE

    Lafont, Frédéric; Pessel, Nathalie; Balmat, Jean-François; Fliess, Michel

    2013-01-01

    International audience; In spite of a large technical literature, an efficient climate control of a greenhouse remains a very difficult task. Indeed, this process is a complex nonlinear system with strong meteorological disturbances. The newly introduced ''model-free control'' setting is employed here. It is easy to implement, and has already shown excellent performances in many other concrete domains. Successful experimental tests are presented and discussed. They are compared to a Boolean a...

  5. Total laparoscopic gastrocystoplasty: experimental technique in a porcine model

    OpenAIRE

    Frederico R. Romero; Claudemir Trapp; Michael Muntener; Fabio A. Brito; Louis R. Kavoussi; Thomas W. Jarrett

    2007-01-01

    OBJECTIVE: Describe a unique simplified experimental technique for total laparoscopic gastrocystoplasty in a porcine model. MATERIAL AND METHODS: We performed laparoscopic gastrocystoplasty on 10 animals. The gastroepiploic arch was identified and carefully mobilized from its origin at the pylorus to the beginning of the previously demarcated gastric wedge. The gastric segment was resected with sharp dissection. Both gastric suturing and gastrovesical anastomosis were performed with absorbabl...

  6. A review of experimental models in colorectal carcinogenesis

    OpenAIRE

    Machado, Vanessa Foresto; Feitosa, Marley Ribeiro; Rocha, Jose Joaquim Ribeiro da; Féres, Omar

    2016-01-01

    ABSTRACT Colorectal cancer is the leading cause of malignancy of the gastrointestinal tract. A better understanding of the molecular and cellular changes that lead to the disease is necessary to develop early diagnosis and optimal treatment modalities. Rodent models are rapid, reproducible and exhibit an adenoma-carcinoma sequence similar to that found in humans. The objective of this manuscript is to review the most common chemical carcinogens used to induce experimental tumors and the usual...

  7. Numerical modeling of nitrogen oxide emission and experimental verification

    Directory of Open Access Journals (Sweden)

    Szecowka Lech

    2003-12-01

    Full Text Available The results of nitrogen reduction in combustion process with application of primary method are presented in paper. The reduction of NOx emission, by the recirculation of combustion gasses, staging of fuel and of air was investigated, and than the reduction of NOx emission by simultaneous usage of the mentioned above primary method with pulsatory disturbances.The investigations contain numerical modeling of NOx reduction and experimental verification of obtained numerical calculation results.

  8. Theoretical and experimental investigation of the nonlinear structural dynamics of Fast Breeder Reactor fuel elements

    International Nuclear Information System (INIS)

    Liebe, R.

    1978-04-01

    This study describes theoretical and experimental investigations of the dynamic deformation behavior of single and clustered fuel elements under local fault conditions in a Fast Breeder Reactor core. In particular an energetic molten-fuel-coolant-interaction (FCI) is assumed in one subassembly with corresponding pressure pulses, which may rupture the wrapper and load the adjacent fuel elements impulsively. Associated coherent structural deformation may exceed tolerable and damage the control rods. To attack the outlined coupled fluid-structure-interaction problem it is assumed, that the loading at the structures is known in space and time, and that there is no feedback from the deformation response. Then current FCI-knowledge and experience from underwater core model explosion tests is utilized to estimate upper limits of relevant pulse characteristics. As a first step the static carrying capacity of the rigid-plastic hexagonal wrapper tube is calculated using the methods of limit analysis. Then for a general dynamic simulation of the complete elastoplastic subassembly response the concept of a discrete nonlinear hinge is introduced. A corresponding physical lumped parameter hinge model is presented, and general equations of motion are derived using D'Alembert's principle. Application to the static and dynamic analysis of a single complete fuel element includes the semiempirical modelling of the fuel-pin bundle by a homogeneous compressible medium. Most important conclusions are concerning the capability of the theoretical models, the failure modes and threshold load levels of single as well as clustered SNR-300 fuel elements and the safety relevant finding, that only limited deformations are found in the first row around the incident element. This shows in agreement with explosion test results that the structured and closely spaced fuel elements constitute an effective, inherent barrier against extreme dynamic loadings. (orig.) [de

  9. Experimental study of impact properties of aluminium honeycomb sandwich structure

    Directory of Open Access Journals (Sweden)

    Flasar Ondrej

    2017-01-01

    Full Text Available Aircraft grade of structural sandwich plates has been studied to determine the influence rate of particular face sheets adjustments on impact energy absorption. The face sheets were fabricated by carbon fibre reinforced plastic (CFRP laminas using unidirectional reinforcement with either cross-ply [0/90]n or angle-ply [±45]n orientation of fibres. A core of the sandwich plates was then formed by aluminium honeycomb. The impact properties of small unnotched sandwich specimens were measured by instrumented Charpy impact test device. Assessment of force-displacement curve, loading process and failure mode was carried out for each specimen type to determine a general trend for increasing the impact properties of sandwich structures.

  10. Wave-Structure Interactions on Point Absorbers - an experimental study

    DEFF Research Database (Denmark)

    Jakobsen, Morten Møller

    : A practical and reliable method to run experiments with combined waves and current. Loads on a WEC’s are affected by currents both directly and indirectly. The current adds to the particle velocity around the device and affects the shape of the waves. Work is carried out to find a way to make experiments...... of a wave energy device by determin- ing the loads on the device. The loads plays a key part in optimizing the power extraction, reducing the structural cost, and increasing the survivabil- ity. Experiments are carried out in small and large scale and compared to simulations and empirical functions. The WEC...... been done to determine peak pressures on mono-piles worldwide, but only very little on spherical structures. In order to shed more light on the wave induced loads on a hemisphere the peak pressures are measured with the traditional drop test and during impact of so-called freak waves. 3: Implementation...

  11. Experimental model of cutaneous radiation injury in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Meirelles, Rafael Panisi de Campos [Universidade Federal de Sao Paulo (EPM/UNIFESP), SP (Brazil). Escola Paulista de Medicina; Hochman, Bernardo [Universidade Federal de Sao Paulo (EPM/UNIFESP), SP (Brazil). Escola Paulista de Medicina. Dept. de Cirurgia; Helene Junior, Americo; Fraga, Murillo Francisco Pires [Faculdade de Ciencias Medicas da Santa Casa de Sao Paulo (FCMSCSP), SP (Brazil). Dept. de Cirurgia. Divisao de Cirurgia Plastica; Lellis, Rute [Faculdade de Ciencias Medicas da Santa Casa de Sao Paulo (FCMSCSP), SP (Brazil). Divisao de Patologia; Ferreira, Lydia Masako, E-mail: rpcmeirelles@yahoo.com.br, E-mail: lydia.dcir@epm.br [Universidade Federal de Sao Paulo (EPM/UNIFESP), SP (Brazil). Escola Paulista de Mediciana. Divisao de Cirugia Plastica

    2013-07-01

    Purpose: to describe an experimental model of cutaneous radiation injury in rabbits. Methods: on this study eight six-month-old New Zealand male rabbits, with an average weight of 2.5kg were used. They were distributed in four groups (n=2 per group). The control group did not receive radiotherapy and the others received one radiotherapy session of 2000, 3000 and 4500 cGy, respectively. Photographic analysis and histopathological evaluation of the irradiated areas were carried out. Results: after 30 days, the animals from the control group had all their hair grown. In spite of that, the animals from group 2000 cGy had a 60-day alopecia and from group 3000 cGy, a 90-day alopecia. After the 30th day, the 3000cGy group demonstrated 90-day cutaneous radiation injuries, graded 3 and 4. One of the animals from group 4500 cGy died on the 7th day with visceral necrosis. The other from the same group had total skin necrosis. A progressive reduction of glands and blood vessels count and an increase on collagen deposition was observed. Conclusion: The proposed experimental model is reproducible. This study suggests that the dosage 4500cGy is excessive and the 3000 cGy is the most effective for this experimental model of cutaneous radiation injury in rabbits. (author)

  12. Experimental model of heterotopic ossification in Wistar rats

    Energy Technology Data Exchange (ETDEWEB)

    Zotz, T.G.G. [Escola Politécnica, Programa de Pós-Graduação em Tecnologia em Saúde, Pontifícia Universidade Católica do Paraná, Curitiba, PR (Brazil); Paula, J.B. de [Médico,Doutor em Engenharia Biomédica, Curitiba, PR (Brazil); Moser, A.D.L. [Escola Politécnica, Programa de Pós-Graduação em Tecnologia em Saúde, Pontifícia Universidade Católica do Paraná, Curitiba, PR (Brazil)

    2012-04-05

    Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues adjacent to large joints, resulting in joint mobility deficit. In order to determine which treatment techniques are more appropriate for such condition, experimental models of induced heterotopic bone formation have been proposed using heterologous demineralized bone matrix implants and bone morphogenetic protein and other tissues. The objective of the present experimental study was to identify a reliable protocol to induce HO in Wistar rats, based on autologous bone marrow (BM) implantation, comparing 3 different BM volumes and based on literature evidence of this HO induction model in larger laboratory animals. Twelve male Wistar albino rats weighing 350/390 g were used. The animals were anesthetized for blood sampling before HO induction in order to quantify serum alkaline phosphatase (ALP). HO was induced by BM implantation in both quadriceps muscles of these animals, experimental group (EG). Thirty-five days after the induction, another blood sample was collected for ALP determination. The results showed a weight gain in the EG and no significant difference in ALP levels when comparing the periods before and after induction. Qualitative histological analysis confirmed the occurrence of heterotopic ossification in all 12 EG rats. In conclusion, the HO induction model was effective when 0.35 mL autologous BM was applied to the quadriceps of Wistar rats.

  13. Experimental model of cutaneous radiation injury in rabbits

    International Nuclear Information System (INIS)

    Meirelles, Rafael Panisi de Campos; Hochman, Bernardo; Helene Junior, Americo; Fraga, Murillo Francisco Pires; Lellis, Rute; Ferreira, Lydia Masako

    2013-01-01

    Purpose: to describe an experimental model of cutaneous radiation injury in rabbits. Methods: on this study eight six-month-old New Zealand male rabbits, with an average weight of 2.5kg were used. They were distributed in four groups (n=2 per group). The control group did not receive radiotherapy and the others received one radiotherapy session of 2000, 3000 and 4500 cGy, respectively. Photographic analysis and histopathological evaluation of the irradiated areas were carried out. Results: after 30 days, the animals from the control group had all their hair grown. In spite of that, the animals from group 2000 cGy had a 60-day alopecia and from group 3000 cGy, a 90-day alopecia. After the 30th day, the 3000cGy group demonstrated 90-day cutaneous radiation injuries, graded 3 and 4. One of the animals from group 4500 cGy died on the 7th day with visceral necrosis. The other from the same group had total skin necrosis. A progressive reduction of glands and blood vessels count and an increase on collagen deposition was observed. Conclusion: The proposed experimental model is reproducible. This study suggests that the dosage 4500cGy is excessive and the 3000 cGy is the most effective for this experimental model of cutaneous radiation injury in rabbits. (author)

  14. Experimental model of heterotopic ossification in Wistar rats

    International Nuclear Information System (INIS)

    Zotz, T.G.G.; Paula, J.B. de; Moser, A.D.L.

    2012-01-01

    Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues adjacent to large joints, resulting in joint mobility deficit. In order to determine which treatment techniques are more appropriate for such condition, experimental models of induced heterotopic bone formation have been proposed using heterologous demineralized bone matrix implants and bone morphogenetic protein and other tissues. The objective of the present experimental study was to identify a reliable protocol to induce HO in Wistar rats, based on autologous bone marrow (BM) implantation, comparing 3 different BM volumes and based on literature evidence of this HO induction model in larger laboratory animals. Twelve male Wistar albino rats weighing 350/390 g were used. The animals were anesthetized for blood sampling before HO induction in order to quantify serum alkaline phosphatase (ALP). HO was induced by BM implantation in both quadriceps muscles of these animals, experimental group (EG). Thirty-five days after the induction, another blood sample was collected for ALP determination. The results showed a weight gain in the EG and no significant difference in ALP levels when comparing the periods before and after induction. Qualitative histological analysis confirmed the occurrence of heterotopic ossification in all 12 EG rats. In conclusion, the HO induction model was effective when 0.35 mL autologous BM was applied to the quadriceps of Wistar rats

  15. Ionospheric topside models compared with experimental electron density profiles

    Directory of Open Access Journals (Sweden)

    S. M. Radicella

    2005-06-01

    Full Text Available Recently an increasing number of topside electron density profiles has been made available to the scientific community on the Internet. These data are important for ionospheric modeling purposes, since the experimental information on the electron density above the ionosphere maximum of ionization is very scarce. The present work compares NeQuick and IRI models with the topside electron density profiles available in the databases of the ISIS2, IK19 and Cosmos 1809 satellites. Experimental electron content from the F2 peak up to satellite height and electron densities at fixed heights above the peak have been compared under a wide range of different conditions. The analysis performed points out the behavior of the models and the improvements needed to be assessed to have a better reproduction of the experimental results. NeQuick topside is a modified Epstein layer, with thickness parameter determined by an empirical relation. It appears that its performance is strongly affected by this parameter, indicating the need for improvements of its formulation. IRI topside is based on Booker's approach to consider two parts with constant height gradients. It appears that this formulation leads to an overestimation of the electron density in the upper part of the profiles, and overestimation of TEC.

  16. An experimental and kinetic modeling study of glycerol pyrolysis

    International Nuclear Information System (INIS)

    Fantozzi, F.; Frassoldati, A.; Bartocci, P.; Cinti, G.; Quagliarini, F.; Bidini, G.; Ranzi, E.M.

    2016-01-01

    Highlights: • Glycerol pyrolysis can produce about 44–48%v hydrogen at 750–800 °C. • A simplified 452 reactions kinetic model of glycerol pyrolysis has been developed. • The model has good agreement with experimental data. • Non condensable gas yields can reach 70%. - Abstract: Pyrolysis of glycerol, a by-product of the biodiesel industry, is an important potential source of hydrogen. The obtained high calorific value gas can be used either as a fuel for combined heat and power (CHP) generation or as a transportation fuel (for example hydrogen to be used in fuel cells). Optimal process conditions can improve glycerol pyrolysis by increasing gas yield and hydrogen concentration. A detailed kinetic mechanism of glycerol pyrolysis, which involves 137 species and more than 4500 reactions, was drastically simplified and reduced to a new skeletal kinetic scheme of 44 species, involved in 452 reactions. An experimental campaign with a batch pyrolysis reactor was properly designed to further validate the original and the skeletal mechanisms. The comparisons between model predictions and experimental data strongly suggest the presence of a catalytic process promoting steam reforming of methane. High pyrolysis temperatures (750–800 °C) improve process performances and non-condensable gas yields of 70%w can be achieved. Hydrogen mole fraction in pyrolysis gas is about 44–48%v. The skeletal mechanism developed can be easily used in Computational Fluid Dynamic software, reducing the simulation time.

  17. Modelling the harmonized tertiary Institutions Salary Structure ...

    African Journals Online (AJOL)

    This paper analyses the Harmonized Tertiary Institution Salary Structure (HATISS IV) used in Nigeria. The irregularities in the structure are highlighted. A model that assumes a polynomial trend for the zero step salary, and exponential trend for the incremental rates, is suggested for the regularization of the structure.

  18. A Teaching Model for Truss Structures

    Science.gov (United States)

    Bigoni, Davide; Dal Corso, Francesco; Misseroni, Diego; Tommasini, Mirko

    2012-01-01

    A classroom demonstration model has been designed, machined and successfully tested in different learning environments to facilitate understanding of the mechanics of truss structures, in which struts are subject to purely axial load and deformation. Gaining confidence with these structures is crucial for the development of lattice models, which…

  19. Modeling the subsurface structure of sunspots

    NARCIS (Netherlands)

    Moradi, H.; Baldner, C.; Birch, A.C.; Braun, D.C.; Cameron, R.H.; Duvall Jr., T.L.; Gizon, L.; Haber, D.; Hanasoge, S.M.; Hindman, B.W.; Jackiewicz, J.; Khomenko, E.; Komm, R.; Rajaguru, P.; Rempel, M.; Roth, M.; Schlichenmaier, R.; Schunker, H.; Spruit, H.C.; Strassmeier, K.G.; Thompson, M.J.; Zharkov, S.

    2010-01-01

    While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate

  20. Relativistic models of nuclear structure

    International Nuclear Information System (INIS)

    Gillet, V.; Kim, E.J.; Cauvin, M.; Kohmura, T.; Ohnaka, S.

    1991-01-01

    The introduction of the relativistic field formalism for the description of nuclear structure has improved our understanding of fundamental nuclear mechanisms such as saturation or many body forces. We discuss some of these progresses, both in the semi-classical mean field approximation and in a quantized meson field approach. (author)

  1. Systematic effects in CALOR simulation code to model experimental configurations

    International Nuclear Information System (INIS)

    Job, P.K.; Proudfoot, J.; Handler, T.

    1991-01-01

    CALOR89 code system is being used to simulate test beam results and the design parameters of several calorimeter configurations. It has been bench-marked against the ZEUS, Dθ and HELIOS data. This study identifies the systematic effects in CALOR simulation to model the experimental configurations. Five major systematic effects are identified. These are the choice of high energy nuclear collision model, material composition, scintillator saturation, shower integration time, and the shower containment. Quantitative estimates of these systematic effects are presented. 23 refs., 6 figs., 7 tabs

  2. Modeling large underground experimental halls for the superconducting super collider

    International Nuclear Information System (INIS)

    Duan, F.; Mrugala, M.

    1993-01-01

    Geomechanical aspects of the excavation design, and analysis of two large underground experimental halls for the Superconducting Super Collider (SSC), being built in Texas, have been extensively investigated using computer modeling. Each chamber, measuring approximately 350 ft long, 110 ft wide, and 190 ft high, is to be excavated mainly through soft marl and overlying competent limestone. Wall stability is essential not only for ensuring excavation safety but also for meeting strict requirements for chamber stability over the 30-yr design life of the facility. Extensive numerical modeling has played a significant role in the selection of excavation methods, excavation sequence, and rock reinforcement systems. (Author)

  3. Experimental characterization and modeling of an ethanol steam reformer

    DEFF Research Database (Denmark)

    Mandø, Matthias; Bovo, Mirko; Nielsen, Mads Pagh

    2006-01-01

    This work describes the characterization of an ethanol reforming system for a high temperature PEM fuel cell system. High temperature PEM fuel cells are well suited for operation on reformate gas due to the superior CO tolerance compared with low temperature PEM. Steam reforming of liquid biofuels...... (ethanol, bio-diesel etc.) represents sustainable sources of hydrogen for micro Combined Heat and Power (CHP) production as well as Auxiliary Power Units (APUs). The system was experimentally characterized and theoretically modelled using a 1-dimensional system model implemented in MATLAB...

  4. Experimental and numerical analysis of a knee endoprosthesis numerical model

    Directory of Open Access Journals (Sweden)

    L. Zach

    2016-07-01

    Full Text Available The aim of this study is to create and verify a numerical model for a Medin Modular orthopedic knee-joint implant by investigating contact pressure, its distribution and contact surfaces. An experiment using Fuji Prescale pressure sensitive films and a finite element analysis (FEA using Abaqus software were carried out. The experimental data were evaluated using a special designed program and were compared with the results of the analysis. The designed evaluation program had been constructed on the basis of results obtained from a supplementary calibration experiment. The applicability of the numerical model for the real endoprosthesis behavior prediction was proven on the basis of their good correlation.

  5. Scale modeling of reinforced concrete structures subjected to seismic loading

    International Nuclear Information System (INIS)

    Dove, R.C.

    1983-01-01

    Reinforced concrete, Category I structures are so large that the possibility of seismicly testing the prototype structures under controlled conditions is essentially nonexistent. However, experimental data, from which important structural properties can be determined and existing and new methods of seismic analysis benchmarked, are badly needed. As a result, seismic experiments on scaled models are of considerable interest. In this paper, the scaling laws are developed in some detail so that assumptions and choices based on judgement can be clearly recognized and their effects discussed. The scaling laws developed are then used to design a reinforced concrete model of a Category I structure. Finally, how scaling is effected by various types of damping (viscous, structural, and Coulomb) is discussed

  6. Modelling collagen diseases: STRUCTURAL BIOLOGY

    OpenAIRE

    Brodsky, Barbara; Baum, Jean

    2008-01-01

    Mutations in collagen lead to hereditary disorders such as brittle-bone disease. Peptide models for aberrant collagens are beginning to clarify how these amino-acid replacements lead to clinical problems.

  7. Structural equation modeling methods and applications

    CERN Document Server

    Wang, Jichuan

    2012-01-01

    A reference guide for applications of SEM using Mplus Structural Equation Modeling: Applications Using Mplus is intended as both a teaching resource and a reference guide. Written in non-mathematical terms, this book focuses on the conceptual and practical aspects of Structural Equation Modeling (SEM). Basic concepts and examples of various SEM models are demonstrated along with recently developed advanced methods, such as mixture modeling and model-based power analysis and sample size estimate for SEM. The statistical modeling program, Mplus, is also featured and provides researchers with a

  8. Experimental Models for Evaluation of Nanoparticles in Cancer Therapy.

    Science.gov (United States)

    Kesharwani, Prashant; Ghanghoria, Raksha; Jain, Narendra K

    2017-01-01

    Nanoparticles (NPs), the submicron-sized colloidal particles, have recently generated enormous interest among biomedical scientists, particularly in cancer therapy. A number of models are being used for exploring NPs safety and efficacy. Recently, cancer cell lines have explored as prominent experimental models for evaluating pharmacokinetic parameters, cell viability, cytotoxicity and drug efficacy in tumor cells. This review aims at thorough compilation of various cancer cell lines and in vivo models for evaluation of efficacy of NPs on one platform. This will provide a basis to explore and improvise pre-clinical models as a prelude to successful cancer research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. Experimental models in vaccine research: malaria and leishmaniasis.

    Science.gov (United States)

    Teixeira, C; Gomes, R

    2013-02-01

    Animal models have a long history of being useful tools, not only to test and select vaccines, but also to help understand the elaborate details of the immune response that follows infection. Different models have been extensively used to investigate putative immunological correlates of protection against parasitic diseases that are important to reach a successful vaccine. The greatest challenge has been the improvement and adaptation of these models to reflect the reality of human disease and the screening of vaccine candidates capable of overcoming the challenge of natural transmission. This review will discuss the advantages and challenges of using experimental animal models for vaccine development and how the knowledge achieved can be extrapolated to human disease by looking into two important parasitic diseases: malaria and leishmaniasis.

  10. A new dietary model to study colorectal carcinogenesis: experimental design, food preparation, and experimental findings.

    Science.gov (United States)

    Rozen, P; Liberman, V; Lubin, F; Angel, S; Owen, R; Trostler, N; Shkolnik, T; Kritchevsky, D

    1996-01-01

    Experimental dietary studies of human colorectal carcinogenesis are usually based on the AIN-76A diet, which is dissimilar to human food in source, preparation, and content. The aims of this study were to examine the feasibility of preparing and feeding rats the diet of a specific human population at risk for colorectal neoplasia and to determine whether changes in the colonic morphology and metabolic contents would differ from those resulting from a standard rat diet. The mean daily food intake composition of a previously evaluated adenoma patient case-control study was used for the "human adenoma" (HA) experimental diet. Foods were prepared as for usual human consumption and processed by dehydration to the physical characteristics of an animal diet. Sixty-four female Sprague-Dawley rats were randomized and fed ad libitum the HA or the AIN-76A diet. Every eight weeks, eight rats from each group were sacrificed, and the colons and contents were examined. Analysis of the prepared food showed no significant deleterious changes; food intake and weight gain were similar in both groups. Compared with the controls, the colonic contents of rats fed the HA diet contained significantly less calcium, concentrations of neutral sterols, total lipids, and cholic and deoxycholic acids were increased, and there were no colonic histological changes other than significant epithelial hyperproliferation. This initial study demonstrated that the HA diet can be successfully processed for feeding to experimental animals and is acceptable and adequate for growth but induces significant metabolic and hyperproliferative changes in the rat colon. This dietary model may be useful for studies of human food, narrowing the gap between animal experimentation and human nutritional research.

  11. Network structure exploration via Bayesian nonparametric models

    International Nuclear Information System (INIS)

    Chen, Y; Wang, X L; Xiang, X; Tang, B Z; Bu, J Z

    2015-01-01

    Complex networks provide a powerful mathematical representation of complex systems in nature and society. To understand complex networks, it is crucial to explore their internal structures, also called structural regularities. The task of network structure exploration is to determine how many groups there are in a complex network and how to group the nodes of the network. Most existing structure exploration methods need to specify either a group number or a certain type of structure when they are applied to a network. In the real world, however, the group number and also the certain type of structure that a network has are usually unknown in advance. To explore structural regularities in complex networks automatically, without any prior knowledge of the group number or the certain type of structure, we extend a probabilistic mixture model that can handle networks with any type of structure but needs to specify a group number using Bayesian nonparametric theory. We also propose a novel Bayesian nonparametric model, called the Bayesian nonparametric mixture (BNPM) model. Experiments conducted on a large number of networks with different structures show that the BNPM model is able to explore structural regularities in networks automatically with a stable, state-of-the-art performance. (paper)

  12. Experimental evidence for a shell structure of the proton

    Energy Technology Data Exchange (ETDEWEB)

    Levintov, I.I.

    1983-11-01

    Spin effects in nucleon-nucleon scattering are explained by the interaction of Fock configurations of the type (qqQQ-barq), having the structure of p shells. The number of nucleon p shells is N = n/sub f/ -1 (n/sub f/ is the number of flavors). The strong spin effect in p/sub arrow-up/p/sub arrow-up/ scattering for p/sup 2//sub perpendicular/ > or approx. =4 (GeV/c)/sup 2/ (the Argonne effect) is explained by the presence of the configuration (qqcc-barq) in the proton. An analogous effect in the region p/sup 2//sub perpendicular/ > or approx. =100 (GeV/c)/sup 2/, due to the configuration (qqbb-barq), is predicted. In scattering of unpolarized hadrons by a polarized proton target for constant theta/sub cms/ and variation of s (i.e., p/sup 2//sub perpendicular/), it is predicted that there are structures in the asymmetry in the region p/sup 2//sub perpendicular/ approx.4m/sup 2//sub Q/ (Q = c, b, ...).

  13. Computational studies of experimentally observed structures of sulfur on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, Dominic

    2011-09-01

    First-principles electronic structure calculations were carried out to examine the experimentally observed structures of sulfur on close packed surfaces of a number of important metals - Ag(111), Cu(111), Ni(111), Pt(111), Rh(111), Re(0001) and Ru(0001). At low coverages ({le} 1/3 ML), the prediction is consistent with the typical pattern of preferred sulfur occupancy of threefold hollow sites, notably the fcc site on the (111) surfaces and the hcp site on the (0001) surfaces. Theoretical confirmation for the existence of pure sulfur overlayer phases on Pt(111), Rh(111), Re(0001) and Ru(0001) at higher coverages (> 1/3 ML) was provided. For the ({radical}7 x {radical}7) phase seen on Ag(111), the most preferred structure identified for adsorbed S trimer consists of an S atom on the top site bonded to two S atoms situated on the nearest neighbor off-bridge site positions. Among the different densely packed mixed sulfur-metal overlayer models suggested for the ({radical}7 x {radical}7) phase on Cu(111), the structure which consists of metal and S atoms in a hexagonal-like arrangement on the top substrate was found to be the most energetically favorable. For the (5{radical}3 x 2) phase on Ni(111), the calculations confirm the existence of clock-reconstructed top layer metal atoms onto which sulfur atoms are adsorbed.

  14. Colloids and Radionuclide Transport: A Field, Experimental and Modeling Effort

    Science.gov (United States)

    Zhao, P.; Zavarin, M.; Sylwester, E. E.; Allen, P. G.; Williams, R. W.; Kersting, A. B.

    2002-05-01

    Natural inorganic colloids (colloid-facilitated transport to the transport of low-solubility actinides, such as Pu, is still not well understood. In an effort to better understand the dominant geochemical mechanisms that control Pu transport, we have performed a series of sorption/desorption experiments using mineral colloids. We focused on natural colloidal minerals present in water samples collected from both saturated and vadose zone waters at the Nevada Test Site. These minerals include zeolites, clays, silica, Mn-oxides, Fe-oxides, and calcite. X-ray absorption fine-structure spectroscopy ( both XANES and EXAFS) was performed in order to characterize the speciation of sorbed plutonium. The XANES spectra show that only Pu(IV) was detected (within experimental error) on these mineral surfaces when the starting Pu oxidation state was +5, indicating that Pu(V) was reduced to Pu(IV) during sorption. The EXAFS detected Pu-M and Pu-C interactions (where M=Fe, Mn, or Si) indicating Pu(IV) surface complexation along with carbonate ternary complex formation on most of the minerals tested. Although the plutonium sorption as Pu(IV) species is mineral independent, the actual sorption paths are different for different minerals. The sorption rates were compared to the rates of plutonium disproportionation under similar conditions. The batch sorption/desorption experiments of Pu(IV) and Pu(V) onto colloidal zeolite (clinoptilolite, colloids particle size 171 ñ 25 nm) were conducted in synthetic groundwater (similar to J-13, Yucca Mountain standard) with a pH range from 4 to 10 and initial plutonium concentration of 10-9 M. The results show that Pu(IV) sorption takes place within an hour, while the rates of Pu(V) sorption onto the colloids is much slower and mineral dependent. The kinetic results from the batch sorption/desorption experiments, coupled with redox kinetics of plutonium in solution will be used in geochemical modeling of Pu surface complexation to colloids and

  15. Experimental model of cultured keratinocytes Modelo experimental de cultura de queratinócitos

    Directory of Open Access Journals (Sweden)

    Alfredo Gragnani

    2003-01-01

    Full Text Available The bioengineering research is essential in the development of ideal combination of biomaterials and cultured cells to produce the permanent wound coverage. The experimental model of cultured keratinocytes presents all steps of the culture, since the isolation of the keratinocytes, preparation of the human acellular dermis, preparation of the composite skin graft and their elevation to the air-liquid interface. The research in cultured keratinocytes model advances in two main ways: 1. optimization of the methods in vitro to the skin cells culture and proliferation and 2. developing biomaterials that present similar skin properties.A pesquisa em bioengenharia é primordial no desenvolvimento da combinação ideal de biomateriais e células cultivadas para produzir a cobertura definitiva das lesões. O modelo experimental da cultura de queratinócitos apresenta toda as etapas do cultivo, desde o isolamento dos queratinócitos, preparação da derme acelular humana, do enxerto composto e da sua elevação à interface ar-líquido. A pesquisa em modelo de cultura de queratinócitos desenvolve-se em duas vias principais: 1. otimização dos métodos in vitro para cultivo e proliferação de células da pele e 2. desenvolvimento de biomateriais que mimetizem as propriedades da pele.

  16. Use of linear programming models in experimentation with plant nutrients

    Directory of Open Access Journals (Sweden)

    Mauro Brino Garcia

    2013-06-01

    Full Text Available Nutrition is an important issue of plant cultivation and experimentation with plant nutrients is a supporting tool for agriculture. However, use of high purity grade reagents as nutrient sources can be expensive and increases the cost of an experiment. The objective of this study was to minimize the acquisition cost of high purity grade reagents in experiments on plant nutrient deficiency by using the missing element technique through linear programming models, and to generate recommendation tables for preparation of culture solutions, as well as to quantify gains through a simulated experiment. Two linear programming models were formulated containing concentration constraints for each nutrient in the culture solution. Model A was based on 16 reagents for preparation of the culture solution, while model B was based on 27 reagents, looking to increase choice options. Results showed that both models minimized the acquisition cost of reagents, allowing a 9.03% reduction in model A and a 25.98% reduction in model B. The missing sulfur treatment proved the most costly for reagent acquisition while the missing nitrogen treatment proved the least costly. It was concluded that the formulated models were capable of reducing acquisition costs of reagents, yet the recommendations generated by them should be tested and checked for practical viability.

  17. Multi-type sensor placement and response reconstruction for building structures: Experimental investigations

    Science.gov (United States)

    Hu, Rong-Pan; Xu, You-Lin; Zhan, Sheng

    2018-01-01

    Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement information from the limited number of sensors installed in a building structure is often insufficient for the complete structural performance assessment. An integrated multi-type sensor placement and response reconstruction method has thus been proposed by the authors to tackle this problem. To validate the feasibility and effectiveness of the proposed method, an experimental investigation using a cantilever beam with multi-type sensors is performed and reported in this paper. The experimental setup is first introduced. The finite element modelling and model updating of the cantilever beam are then performed. The optimal sensor placement for the best response reconstruction is determined by the proposed method based on the updated FE model of the beam. After the sensors are installed on the physical cantilever beam, a number of experiments are carried out. The responses at key locations are reconstructed and compared with the measured ones. The reconstructed responses achieve a good match with the measured ones, manifesting the feasibility and effectiveness of the proposed method. Besides, the proposed method is also examined for the cases of different excitations and unknown excitation, and the results prove the proposed method to be robust and effective. The superiority of the optimized sensor placement scheme is finally demonstrated through comparison with two other different sensor placement schemes: the accelerometer-only scheme and non-optimal sensor placement scheme. The proposed method can be applied to high-rise buildings for seismic performance assessment.

  18. Quality assessment of protein model-structures based on structural and functional similarities.

    Science.gov (United States)

    Konopka, Bogumil M; Nebel, Jean-Christophe; Kotulska, Malgorzata

    2012-09-21

    Experimental determination of protein 3D structures is expensive, time consuming and sometimes impossible. A gap between number of protein structures deposited in the World Wide Protein Data Bank and the number of sequenced proteins constantly broadens. Computational modeling is deemed to be one of the ways to deal with the problem. Although protein 3D structure prediction is a difficult task, many tools are available. These tools can model it from a sequence or partial structural information, e.g. contact maps. Consequently, biologists have the ability to generate automatically a putative 3D structure model of any protein. However, the main issue becomes evaluation of the model quality, which is one of the most important challenges of structural biology. GOBA--Gene Ontology-Based Assessment is a novel Protein Model Quality Assessment Program. It estimates the compatibility between a model-structure and its expected function. GOBA is based on the assumption that a high quality model is expected to be structurally similar to proteins functionally similar to the prediction target. Whereas DALI is used to measure structure similarity, protein functional similarity is quantified using standardized and hierarchical description of proteins provided by Gene Ontology combined with Wang's algorithm for calculating semantic similarity. Two approaches are proposed to express the quality of protein model-structures. One is a single model quality assessment method, the other is its modification, which provides a relative measure of model quality. Exhaustive evaluation is performed on data sets of model-structures submitted to the CASP8 and CASP9 contests. The validation shows that the method is able to discriminate between good and bad model-structures. The best of tested GOBA scores achieved 0.74 and 0.8 as a mean Pearson correlation to the observed quality of models in our CASP8 and CASP9-based validation sets. GOBA also obtained the best result for two targets of CASP8, and

  19. Determination of solubility profiles of eflucimibe polymorphs: experimental and modeling.

    Science.gov (United States)

    Teychene, S; Autret, J M; Biscans, B

    2006-04-01

    This work presents the determination of the phase diagram of two polymorphs of Eflucimibe in pure solvents and solvent mixtures at different temperatures. Solid phase changes were analysed by Differential Scanning Calorimetry. Solubility measurements show that the solubility of the two forms are very similar. Experimental data obtained in ethanol, reported in a Van t'Hoff plot, exhibit a transition temperature around 265 K. A single maximum is observed when solubility is plotted against the solubility parameters of solvents or solvent mixture and it is not related to a solid phase change. This phenomenon, known as a positive synergetic effect, has been explained in term of evolution of solute-solvents polar interactions. Several thermodynamics models (UNIFAC, UNIQUAC, Wilson, Scatchard Hildebrand ... ) were tested in order to predict the Liquid-Solid Equilibrium for this system. The semi empirical model UNIQUAC gives the best fit. The results obtained are in good agreement with the experimental data (mean deviation lower than 5%) and the solubility maximum found experimentally for each polymorph is also well described.

  20. DMFC anode polarization: Experimental analysis and model validation

    Science.gov (United States)

    Casalegno, A.; Marchesi, R.

    Anode two-phase flow has an important influence on DMFC performance and methanol crossover. In order to elucidate two-phase flow influence on anode performance, in this work, anode polarization is investigated combining experimental and modelling approach. A systematic experimental analysis of operating conditions influence on anode polarization is presented. Hysteresis due to operating condition is observed; experimental results suggest that it arises from methanol accumulation and has to be considered in evaluating DMFC performances and measurements reproducibility. A model of DMFC anode polarization is presented and utilised as tool to investigate anode two-phase flow. The proposed analysis permits one to produce a confident interpretation of the main involved phenomena. In particular, it confirms that methanol electro-oxidation kinetics is weakly dependent on methanol concentration and that methanol transport in gas phase produces an important contribution in anode feeding. Moreover, it emphasises the possibility to optimise anode flow rate in order to improve DMFC performance and reduce methanol crossover.

  1. Experimental analysis models for studying the dynamic behaviour of turbine shrouded bladed disk assemblies

    International Nuclear Information System (INIS)

    Costa, B.

    1996-05-01

    The study presented concerns the final blade assembly of a low-pressure body in an electric power station. The ultimate objective of the study is to check whether the fatigue damage is acceptable and that the actual stresses do not excite the bladed disk assembly in its own modes. A combined methodology of calculations and tests was adopted to carry out this test. The calculation part involves modelization, by finite elements, of the bladed disk assembly. This paper presents only the experimental part, i.e. the tests, and experimental analysis methods and models. Experimental analysis poses special problems on account of the complexity of the dynamic behaviour of this type of structure and the limited number of available measuring points. (author). 9 refs

  2. The Monotonicity Puzzle: An Experimental Investigation of Incentive Structures

    Directory of Open Access Journals (Sweden)

    Jeannette Brosig

    2010-05-01

    Full Text Available Non-monotone incentive structures, which - according to theory - are able to induce optimal behavior, are often regarded as empirically less relevant for labor relationships. We compare the performance of a theoretically optimal non-monotone contract with a monotone one under controlled laboratory conditions. Implementing some features relevant to real-world employment relationships, our paper demonstrates that, in fact, the frequency of income-maximizing decisions made by agents is higher under the monotone contract. Although this observed behavior does not change the superiority of the non-monotone contract for principals, they do not choose this contract type in a significant way. This is what we call the monotonicity puzzle. Detailed investigations of decisions provide a clue for solving the puzzle and a possible explanation for the popularity of monotone contracts.

  3. Quantitative structure - mesothelioma potency model ...

    Science.gov (United States)

    Cancer potencies of mineral and synthetic elongated particle (EP) mixtures, including asbestos fibers, are influenced by changes in fiber dose composition, bioavailability, and biodurability in combination with relevant cytotoxic dose-response relationships. A unique and comprehensive rat intra-pleural (IP) dose characterization data set with a wide variety of EP size, shape, crystallographic, chemical, and bio-durability properties facilitated extensive statistical analyses of 50 rat IP exposure test results for evaluation of alternative dose pleural mesothelioma response models. Utilizing logistic regression, maximum likelihood evaluations of thousands of alternative dose metrics based on hundreds of individual EP dimensional variations within each test sample, four major findings emerged: (1) data for simulations of short-term EP dose changes in vivo (mild acid leaching) provide superior predictions of tumor incidence compared to non-acid leached data; (2) sum of the EP surface areas (ÓSA) from these mildly acid-leached samples provides the optimum holistic dose response model; (3) progressive removal of dose associated with very short and/or thin EPs significantly degrades resultant ÓEP or ÓSA dose-based predictive model fits, as judged by Akaike’s Information Criterion (AIC); and (4) alternative, biologically plausible model adjustments provide evidence for reduced potency of EPs with length/width (aspect) ratios 80 µm. Regar

  4. Visualizing Experimental Designs for Balanced ANOVA Models using Lisp-Stat

    Directory of Open Access Journals (Sweden)

    Philip W. Iversen

    2004-12-01

    Full Text Available The structure, or Hasse, diagram described by Taylor and Hilton (1981, American Statistician provides a visual display of the relationships between factors for balanced complete experimental designs. Using the Hasse diagram, rules exist for determining the appropriate linear model, ANOVA table, expected means squares, and F-tests in the case of balanced designs. This procedure has been implemented in Lisp-Stat using a software representation of the experimental design. The user can interact with the Hasse diagram to add, change, or delete factors and see the effect on the proposed analysis. The system has potential uses in teaching and consulting.

  5. Comparative sequence and structural analyses of G-protein-coupled receptor crystal structures and implications for molecular models.

    Directory of Open Access Journals (Sweden)

    Catherine L Worth

    Full Text Available BACKGROUND: Up until recently the only available experimental (high resolution structure of a G-protein-coupled receptor (GPCR was that of bovine rhodopsin. In the past few years the determination of GPCR structures has accelerated with three new receptors, as well as squid rhodopsin, being successfully crystallized. All share a common molecular architecture of seven transmembrane helices and can therefore serve as templates for building molecular models of homologous GPCRs. However, despite the common general architecture of these structures key differences do exist between them. The choice of which experimental GPCR structure(s to use for building a comparative model of a particular GPCR is unclear and without detailed structural and sequence analyses, could be arbitrary. The aim of this study is therefore to perform a systematic and detailed analysis of sequence-structure relationships of known GPCR structures. METHODOLOGY: We analyzed in detail conserved and unique sequence motifs and structural features in experimentally-determined GPCR structures. Deeper insight into specific and important structural features of GPCRs as well as valuable information for template selection has been gained. Using key features a workflow has been formulated for identifying the most appropriate template(s for building homology models of GPCRs of unknown structure. This workflow was applied to a set of 14 human family A GPCRs suggesting for each the most appropriate template(s for building a comparative molecular model. CONCLUSIONS: The available crystal structures represent only a subset of all possible structural variation in family A GPCRs. Some GPCRs have structural features that are distributed over different crystal structures or which are not present in the templates suggesting that homology models should be built using multiple templates. This study provides a systematic analysis of GPCR crystal structures and a consistent method for identifying

  6. Comparative sequence and structural analyses of G-protein-coupled receptor crystal structures and implications for molecular models.

    Science.gov (United States)

    Worth, Catherine L; Kleinau, Gunnar; Krause, Gerd

    2009-09-16

    Up until recently the only available experimental (high resolution) structure of a G-protein-coupled receptor (GPCR) was that of bovine rhodopsin. In the past few years the determination of GPCR structures has accelerated with three new receptors, as well as squid rhodopsin, being successfully crystallized. All share a common molecular architecture of seven transmembrane helices and can therefore serve as templates for building molecular models of homologous GPCRs. However, despite the common general architecture of these structures key differences do exist between them. The choice of which experimental GPCR structure(s) to use for building a comparative model of a particular GPCR is unclear and without detailed structural and sequence analyses, could be arbitrary. The aim of this study is therefore to perform a systematic and detailed analysis of sequence-structure relationships of known GPCR structures. We analyzed in detail conserved and unique sequence motifs and structural features in experimentally-determined GPCR structures. Deeper insight into specific and important structural features of GPCRs as well as valuable information for template selection has been gained. Using key features a workflow has been formulated for identifying the most appropriate template(s) for building homology models of GPCRs of unknown structure. This workflow was applied to a set of 14 human family A GPCRs suggesting for each the most appropriate template(s) for building a comparative molecular model. The available crystal structures represent only a subset of all possible structural variation in family A GPCRs. Some GPCRs have structural features that are distributed over different crystal structures or which are not present in the templates suggesting that homology models should be built using multiple templates. This study provides a systematic analysis of GPCR crystal structures and a consistent method for identifying suitable templates for GPCR homology modelling that will

  7. Analytical modelling and experimental studies of SIS tunnel solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheknane, Ali [Laboratoire de Valorisation des Energies Renouvelables et Environnements Agressifs, Universite Amar Telidji de Laghouat, BP 37G route de Ghardaia, Laghouat (03000) Algerie (Algeria)], E-mail: cheknanali@yahoo.com

    2009-06-07

    This paper presents an experimental and computational study of semiconductor-insulator-semiconductor (SIS) tunnel solar cells. A transparent and conductive film of thallium trioxide Tl{sub 2}O{sub 3} has been deposited by anodic oxidation onto an n-Si(1 0 0) face to realize the SIS tunnel solar cells based on Si/SiO{sub x}/Tl{sub 2}O{sub 3}. An efficiency of 8.77% has been obtained under an incident power density of 33 mW cm{sup -2} illumination condition. A PSPICE model is implemented. The calculated results show that the theoretical values are in good agreement with experimental data. Moreover, the simulation clearly demonstrates that the performance of the tested device can be significantly improved.

  8. Experimental limits from ATLAS on Standard Model Higgs production.

    CERN Multimedia

    ATLAS, collaboration

    2012-01-01

    Experimental limits from ATLAS on Standard Model Higgs production in the mass range 110-600 GeV. The solid curve reflects the observed experimental limits for the production of a Higgs of each possible mass value (horizontal axis). The region for which the solid curve dips below the horizontal line at the value of 1 is excluded with a 95% confidence level (CL). The dashed curve shows the expected limit in the absence of the Higgs boson, based on simulations. The green and yellow bands correspond (respectively) to 68%, and 95% confidence level regions from the expected limits. Higgs masses in the narrow range 123-130 GeV are the only masses not excluded at 95% CL

  9. Experimental investigations and modelling of sodium-concrete interaction

    International Nuclear Information System (INIS)

    Schultheiss, G.F.; Deeg, H.J.

    1990-01-01

    The use of sodium as a coolant in liquid metal fast breeder reactors, fusion reactors, and solar plants requires special consideration of its chemical reactivity and related safety problems in the case of sodium leckage. On contact between hot sodium and concrete an interaction takes place resulting in energy release and hydrogen generation, which may contribute to containment loading by pressurization in a hypothetical accident situation. For this reason, sodium-concrete interactions were investigated experimentally and theoretically. The experiments revealed important effects of quartzitic material within the concrete and of the sodium temperature on the interaction mechanisms, the energy release and the consequent hydrogen production. The numerical model shows good agreement with the experimental results. (orig.) [de

  10. The echinoderm larval skeleton as a possible model system for experimental evolutionary biology.

    Science.gov (United States)

    Koga, Hiroyuki; Morino, Yoshiaki; Wada, Hiroshi

    2014-03-01

    The evolution of various body plans results from the acquisition of novel structures as well as the loss of existing structures. Some novel structures necessitate multiple evolutionary steps, requiring organisms to overcome the intermediate steps, which might be less adaptive or neutral. To examine this issue, echinoderms might provide an ideal experimental system. A larval skeleton is acquired in some echinoderm lineages, such as sea urchins, probably via the co-option of the skeletogenic machinery that was already established to produce the adult skeleton. The acquisition of a larval skeleton was found to require multiple steps and so provides a model experimental system for reproducing intermediate evolutionary stages. The fact that echinoderm embryology has been studied with various natural populations also presents an advantage. Copyright © 2014 Wiley Periodicals, Inc.

  11. EXPERIMENTAL RESEARCH OF THE THREE-DIMENSIONAL PERFORMANCE OF COMPOSITE STEEL AND CONCRETE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Zamaliev Farit Sakhapovich

    2012-12-01

    steel-concrete slabs limits their use in the construction of residential housing. This article describes the composition, geometry, reinforcement, and anchors to enable the use of concrete slabs and steel beams. The article contains photographs that illustrate the load distribution model. Methods of testing of fiber strains of concrete slabs and steel profiles, deflections of beams, shear stresses in the layers of the "steel-to-concrete" contact area that may involve slab cracking are analyzed. Dynamics of fiber deformations of concrete slabs, steel beams, and layers of the "steel-to-concrete" contact areas, deflection development patterns, initial cracking and crack development to destruction are analyzed. The author also describes the fracture behavior of the floor model. Results of experimental studies of the three-dimensional overlapping of structural elements are compared to the test data of individual composite beams. Peculiarities of the stress-strain state of composite steel and concrete slabs, graphs of strains and stresses developing in sections of middle and external steel-and-concrete beams, deflection graphs depending on the loading intensity are provided. The findings of the experimental studies of the three-dimensional performance of composite steel-and-concrete slabs are provided, as well.

  12. Continuum damage modeling through theoretical and experimental pressure limit formulas

    Directory of Open Access Journals (Sweden)

    Fatima Majid

    2018-01-01

    Full Text Available In this paper, we developed a mathematical modeling to represent the damage of thermoplastic pipes. On the one hand, we adapted the theories of the rupture pressure to fit the High Density Polyethylene (HDPE case. Indeed, the theories for calculating the rupture pressure are multiple, designed originally for steels and alloys. For polymer materials, we have found that these theories can be adapted using a coefficient related to the nature of the studied material. The HDPE is characterized by two important values of pressure, deduced from the ductile form of the internal pressures evolution until burst. For this reason, we have designed an alpha coefficient taking into account these two pressures and giving a good approximation of the evolution of the experimental burst pressures through the theoretically corrected ones, using Faupel㒒s pressure formula. Then, we can deduce the evolution of the theoretical damage using the calculated pressures. On the other hand, two other mathematical models were undertaken. The first one has given rise to an adaptive model referring to an expression of the pressure as a function of the life fraction, the characteristic pressures and the critical life fraction. The second model represents a continuum damage model incorporating the pressure equations as a function of the life fraction and based on the burst pressure�s static damage model. These models represent important tools for industrials to assess the failure of thermoplastic pipes and proceed quick checks

  13. Short note: the experimental geopotential model XGM2016

    Science.gov (United States)

    Pail, R.; Fecher, T.; Barnes, D.; Factor, J. F.; Holmes, S. A.; Gruber, T.; Zingerle, P.

    2018-04-01

    As a precursor study for the upcoming combined Earth Gravitational Model 2020 (EGM2020), the Experimental Gravity Field Model XGM2016, parameterized as a spherical harmonic series up to degree and order 719, is computed. XGM2016 shares the same combination methodology as its predecessor model GOCO05c (Fecher et al. in Surv Geophys 38(3): 571-590, 2017. doi: 10.1007/s10712-016-9406-y). The main difference between these models is that XGM2016 is supported by an improved terrestrial data set of 15^' × 15^' gravity anomaly area-means provided by the United States National Geospatial-Intelligence Agency (NGA), resulting in significant upgrades compared to existing combined gravity field models, especially in continental areas such as South America, Africa, parts of Asia, and Antarctica. A combination strategy of relative regional weighting provides for improved performance in near-coastal ocean regions, including regions where the altimetric data are mostly unchanged from previous models. Comparing cumulative height anomalies, from both EGM2008 and XGM2016 at degree/order 719, yields differences of 26 cm in Africa and 40 cm in South America. These differences result from including additional information of satellite data, as well as from the improved ground data in these regions. XGM2016 also yields a smoother Mean Dynamic Topography with significantly reduced artifacts, which indicates an improved modeling of the ocean areas.

  14. Short note: the experimental geopotential model XGM2016

    Science.gov (United States)

    Pail, R.; Fecher, T.; Barnes, D.; Factor, J. F.; Holmes, S. A.; Gruber, T.; Zingerle, P.

    2017-10-01

    As a precursor study for the upcoming combined Earth Gravitational Model 2020 (EGM2020), the Experimental Gravity Field Model XGM2016, parameterized as a spherical harmonic series up to degree and order 719, is computed. XGM2016 shares the same combination methodology as its predecessor model GOCO05c (Fecher et al. in Surv Geophys 38(3): 571-590, 2017. doi: 10.1007/s10712-016-9406-y). The main difference between these models is that XGM2016 is supported by an improved terrestrial data set of 15^' × 15^' gravity anomaly area-means provided by the United States National Geospatial-Intelligence Agency (NGA), resulting in significant upgrades compared to existing combined gravity field models, especially in continental areas such as South America, Africa, parts of Asia, and Antarctica. A combination strategy of relative regional weighting provides for improved performance in near-coastal ocean regions, including regions where the altimetric data are mostly unchanged from previous models. Comparing cumulative height anomalies, from both EGM2008 and XGM2016 at degree/order 719, yields differences of 26 cm in Africa and 40 cm in South America. These differences result from including additional information of satellite data, as well as from the improved ground data in these regions. XGM2016 also yields a smoother Mean Dynamic Topography with significantly reduced artifacts, which indicates an improved modeling of the ocean areas.

  15. Basics of Structural Equation Modeling

    CERN Document Server

    Maruyama, Dr Geoffrey M

    1997-01-01

    With the availability of software programs, such as LISREL, EQS, and AMOS, modeling (SEM) techniques have become a popular tool for formalized presentation of the hypothesized relationships underlying correlational research and test for the plausibility of hypothesizing for a particular data set. Through the use of careful narrative explanation, Maruyama's text describes the logic underlying SEM approaches, describes how SEM approaches relate to techniques like regression and factor analysis, analyzes the strengths and shortcomings of SEM as compared to alternative methodologies, and explores

  16. A two-Higgs-doublet model facing experimental hints

    Directory of Open Access Journals (Sweden)

    Crivellin Andreas

    2016-01-01

    Full Text Available Physics beyond the Standard Model has so far eluded our experimental probes. Nevertheless, a number of interesting anomalies have accumulated that can be taken as hints towards new physics: BaBar, Belle, and LHCb have found deviations of approximately 3:8σ in B → Dτν and B → D*τν; the anomalous magnetic moment of the muon differs by about 3σ from the theoretic prediction; the branching ratio for τ → μνν is about 2σ above the Standard Model expectation; and CMS and ATLAS found hints for a non-zero decay rate of h → μτ at 2.6σ. Here we consider these processes within a lepton-specific two-Higgs doublet model with additional non-standard Yukawa couplings and show how (and which of these excesses can be accommodated.

  17. Experimentation and numerical modeling of forging induced bending (FIB) process

    Science.gov (United States)

    Naseem, S.; van den Boogaard, A. H.

    2016-10-01

    Accurate prediction of the final shape using numerical modeling has been a top priority in the field of sheet and bulk forming. Better shape prediction is the result of a better estimation of the physical stress and strain state. For experimental and numerical investigations of such estimations, simple benchmark processes are used. In this paper a benchmark process involving forging (flattening) of sheet metal between punch and die with negative clearance is proposed. The introduced material flow results in bending. Easy measurability of the angle of this bend makes this process suitable for validation purpose. Physical experiments are performed to characterize this bending angle due to flattening. Furthermore a numerical model is developed to capture this phenomenon. The main focus of this paper is the validation of the numerical model in terms of accurate prediction of the physical results.

  18. Multiplicity Control in Structural Equation Modeling

    Science.gov (United States)

    Cribbie, Robert A.

    2007-01-01

    Researchers conducting structural equation modeling analyses rarely, if ever, control for the inflated probability of Type I errors when evaluating the statistical significance of multiple parameters in a model. In this study, the Type I error control, power and true model rates of famsilywise and false discovery rate controlling procedures were…

  19. A first course in structural equation modeling

    CERN Document Server

    Raykov, Tenko

    2012-01-01

    In this book, authors Tenko Raykov and George A. Marcoulides introduce students to the basics of structural equation modeling (SEM) through a conceptual, nonmathematical approach. For ease of understanding, the few mathematical formulas presented are used in a conceptual or illustrative nature, rather than a computational one.Featuring examples from EQS, LISREL, and Mplus, A First Course in Structural Equation Modeling is an excellent beginner's guide to learning how to set up input files to fit the most commonly used types of structural equation models with these programs. The basic ideas and methods for conducting SEM are independent of any particular software.Highlights of the Second Edition include: Review of latent change (growth) analysis models at an introductory level Coverage of the popular Mplus program Updated examples of LISREL and EQS A CD that contains all of the text's LISREL, EQS, and Mplus examples.A First Course in Structural Equation Modeling is intended as an introductory book for students...

  20. Image-Based Structural Modeling of the Cardiac Purkinje Network

    Directory of Open Access Journals (Sweden)

    Benjamin R. Liu

    2015-01-01

    Full Text Available The Purkinje network is a specialized conduction system within the heart that ensures the proper activation of the ventricles to produce effective contraction. Its role during ventricular arrhythmias is less clear, but some experimental studies have suggested that the Purkinje network may significantly affect the genesis and maintenance of ventricular arrhythmias. Despite its importance, few structural models of the Purkinje network have been developed, primarily because current physical limitations prevent examination of the intact Purkinje network. In previous modeling efforts Purkinje-like structures have been developed through either automated or hand-drawn procedures, but these networks have been created according to general principles rather than based on real networks. To allow for greater realism in Purkinje structural models, we present a method for creating three-dimensional Purkinje networks based directly on imaging data. Our approach uses Purkinje network structures extracted from photographs of dissected ventricles and projects these flat networks onto realistic endocardial surfaces. Using this method, we create models for the combined ventricle-Purkinje system that can fully activate the ventricles through a stimulus delivered to the Purkinje network and can produce simulated activation sequences that match experimental observations. The combined models have the potential to help elucidate Purkinje network contributions during ventricular arrhythmias.

  1. MODEL OF STRATEGIC MANAGEMENT STRUCTURE OF AGROHOLDING

    Directory of Open Access Journals (Sweden)

    Александр Витальевич ШМАТКО

    2015-06-01

    Full Text Available This article describes the main problems of functioning of the agricultural holding, the analysis of literature on strategic management of agricultural holdin gs. Revealed the main disadvantage of the existing approaches, namely - they rely on the existing structure of the holding, not considering that the structure itself is a complex for the analysis and understanding. The basic methods and models of organizational structure of agricultural holdings. Are discrete model of the management structure of agricultural holdings, which minimizes costs associated with attracting candidates to work.

  2. Estresse oxidativo e alterações estruturais pulmonares no diabetes mellitus experimental Experimental diabetes mellitus: oxidative stress and changes in lung structure

    Directory of Open Access Journals (Sweden)

    Luiz Alberto Forgiarini Junior

    2009-08-01

    Full Text Available O diabetes mellitus é uma desordem endócrino-metabólica caracterizada pela hiperglicemia. O seu impacto no sistema respiratório é caracterizado por alterações funcionais e na troca gasosa. O objetivo deste estudo foi avaliar o aumento do estresse oxidativo e os possíveis danos na estrutura pulmonar no modelo de diabetes experimental induzido por estreptozotocina. Foram realizadas análises histológicas, bioquímicas e gasométricas no pulmão de ratos diabéticos. Concluiu-se que o estresse oxidativo está presente no diabetes mellitus experimental e que ocorrem alterações estruturais no tecido pulmonar, bem como alterações na troca gasosa.Diabetes mellitus is an endocrine/metabolic disorder characterized by hyperglycemia. Its impact on the respiratory system is characterized by functional changes and alterations in gas exchange. The objective of this study was to evaluate the increase in oxidative stress and the potential damages to the lung structure in an experimental model of streptozotocin-induced diabetes. We conducted histological, biochemical and blood gas analyses in the lungs of diabetic rats. We concluded that the effects of experimental diabetes mellitus include oxidative stress, structural changes in the lung tissue and altered gas exchange.

  3. Experimental Modal Analysis and Dynaic Strain Fiber Bragg Gratings for Structural Health Monitoring of Composite Aerospace Structures

    Science.gov (United States)

    Panopoulou, A.; Fransen, S.; Gomez Molinero, V.; Kostopoulos, V.

    2012-07-01

    The objective of this work is to develop a new structural health monitoring system for composite aerospace structures based on dynamic response strain measurements and experimental modal analysis techniques. Fibre Bragg Grating (FBG) optical sensors were used for monitoring the dynamic response of the composite structure. The structural dynamic behaviour has been numerically simulated and experimentally verified by means of vibration testing. The hypothesis of all vibration tests was that actual damage in composites reduces their stiffness and produces the same result as mass increase produces. Thus, damage was simulated by slightly varying locally the mass of the structure at different zones. Experimental modal analysis based on the strain responses was conducted and the extracted strain mode shapes were the input for the damage detection expert system. A feed-forward back propagation neural network was the core of the damage detection system. The features-input to the neural network consisted of the strain mode shapes, extracted from the experimental modal analysis. Dedicated training and validation activities were carried out based on the experimental results. The system showed high reliability, confirmed by the ability of the neural network to recognize the size and the position of damage on the structure. The experiments were performed on a real structure i.e. a lightweight antenna sub- reflector, manufactured and tested at EADS CASA ESPACIO. An integrated FBG sensor network, based on the advantage of multiplexing, was mounted on the structure with optimum topology. Numerical simulation of both structures was used as a support tool at all the steps of the work. Potential applications for the proposed system are during ground qualification extensive tests of space structures and during the mission as modal analysis tool on board, being able via the FBG responses to identify a potential failure.

  4. Exploratory experimental investigations on post-tensioned structural glass beams

    Directory of Open Access Journals (Sweden)

    Christian Louter

    2014-06-01

    Full Text Available Corresponding author: Dr. ir. Christian Louter, Steel Structures Laboratory (ICOM, School of Architecture, Civil and Environmental Engineering (ENAC, École Polytechnique Fédérale de Lausanne (EPFL, GC B3 505, Station 18, Lausanne CH-1015, Switzerland. Tel.: +41 21 6932427; Fax: +41 21 6932868; E-mail: christian.louter@epfl.ch The mechanical response of post-tensioned glass beams is explored in this paper. This is done through bending experiments on post-tensioned glass beam specimens with either mechanically anchored or adhesively bonded steel tendons by which a beneficial pre-stress is inflicted on the glass beams. In addition, reference beams with identical geometry but without tendons are tested. From the results of the bending experiments it can be seen that the post-tensioned glass beams reach higher initial fracture loads than the reference glass beams. Furthermore, the post-tensioned glass beams develop a significant post-fracture reserve. From this it is concluded that post-tensioning a glass beam is a feasible concept, which provides increased initial fracture strength and enhanced post-fracture performance.

  5. Experimental Evaluation of the Training Structure of the Picture Exchange Communication System (PECS)

    Science.gov (United States)

    Cummings, Anne R.; Carr, James E.; LeBlanc, Linda A.

    2012-01-01

    The Picture Exchange Communication System (PECS) is a picture-based alternative communication method that is widely accepted and utilized with individuals with disabilities. Although prior studies have examined the clinical efficacy of PECS, none have experimentally evaluated its manualized training structure. We experimentally evaluated the…

  6. Structure functions in the chiral bag model

    Energy Technology Data Exchange (ETDEWEB)

    Sanjose, V.; Vento, V.

    1989-07-13

    We calculate the structure functions of an isoscalar nuclear target for the deep inelastic scattering by leptons in an extended version of the chiral bag model which incorporates the qanti q structure of the pions in the cloud. Bjorken scaling and Regge behavior are satisfied. The model calculation reproduces the low-x behavior of the data but fails to explain the medium- to large-x behavior. Evolution of the quark structure functions seem inevitable to attempt a connection between the low-energy models and the high-energy behavior of quantum chromodynamics. (orig.).

  7. Active vibration control of a cylindrical structure using flexible piezoactuators: experimental work in air and water environments

    Science.gov (United States)

    Sohn, Jung Woo; Choi, Seung-Bok

    2014-10-01

    In the present work, the modal characteristics and vibration control performance of a cylindrical structure in air and water are experimentally investigated, and the results are presented in time and frequency domains. In order to achieve this goal, an end-capped cylindrical shell structure is considered as a host structure, and MFC (macro fiber composite) actuators, which are flexible, are bonded on the surface of the structure. After manufacturing a cylindrical shell structure with aluminum, a modal test is carried out, and the natural frequencies of the proposed structure are obtained and analyzed. To verify the modal test results, a finite element analysis is also performed, and the results are compared with the modal test results. By using the experimentally obtained modal characteristics, a state space control model is established. An optimal controller is then designed in order to control the unwanted vibration and is experimentally realized. It has been shown that the structural vibration can be effectively decreased with the optimal control methodology in both air and water environmental conditions.

  8. A comprehensive experimental and modeling study of 2-methylbutanol combustion

    KAUST Repository

    Park, Sungwoo

    2015-05-01

    2-Methylbutanol (2-methyl-1-butanol) is one of several next-generation biofuels that can be used as an alternative fuel or blending component for combustion engines. This paper presents new experimental data for 2-methylbutanol, including ignition delay times in a high-pressure shock tube and premixed laminar flame speeds in a constant volume combustion vessel. Shock tube ignition delay times were measured for 2-methylbutanol/air mixtures at three equivalence ratios, temperatures ranging from 750 to 1250. K, and at nominal pressures near 20 and 40. bar. Laminar flame speed data were obtained using the spherically propagating premixed flame configuration at pressures of 1, 2, and 5. bar. A detailed chemical kinetic model for 2-methylbutanol oxidation was developed including high- and low-temperature chemistry based on previous modeling studies on butanol and pentanol isomers. The proposed model was tested against new and existing experimental data at pressures of 1-40. atm, temperatures of 740-1636. K, equivalence ratios of 0.25-2.0. Reaction path and sensitivity analyses were conducted for identifying key reactions at various combustion conditions, and to obtain better understanding of the combustion characteristics of larger alcohols.

  9. Neuroinflammatory targets and treatments for epilepsy validated in experimental models.

    Science.gov (United States)

    Aronica, Eleonora; Bauer, Sebastian; Bozzi, Yuri; Caleo, Matteo; Dingledine, Raymond; Gorter, Jan A; Henshall, David C; Kaufer, Daniela; Koh, Sookyong; Löscher, Wolfgang; Louboutin, Jean-Pierre; Mishto, Michele; Norwood, Braxton A; Palma, Eleonora; Poulter, Michael O; Terrone, Gaetano; Vezzani, Annamaria; Kaminski, Rafal M

    2017-07-01

    A large body of evidence that has accumulated over the past decade strongly supports the role of inflammation in the pathophysiology of human epilepsy. Specific inflammatory molecules and pathways have been identified that influence various pathologic outcomes in different experimental models of epilepsy. Most importantly, the same inflammatory pathways have also been found in surgically resected brain tissue from patients with treatment-resistant epilepsy. New antiseizure therapies may be derived from these novel potential targets. An essential and crucial question is whether targeting these molecules and pathways may result in anti-ictogenesis, antiepileptogenesis, and/or disease-modification effects. Therefore, preclinical testing in models mimicking relevant aspects of epileptogenesis is needed to guide integrated experimental and clinical trial designs. We discuss the most recent preclinical proof-of-concept studies validating a number of therapeutic approaches against inflammatory mechanisms in animal models that could represent novel avenues for drug development in epilepsy. Finally, we suggest future directions to accelerate preclinical to clinical translation of these recent discoveries. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

  10. Protection of estrogen in portal hypertension gastropathy: an experimental model

    Directory of Open Access Journals (Sweden)

    Maria Isabel Morgan-Martins

    2011-09-01

    Full Text Available CONTEXT: Portal hypertension is a complication secondary to cirrhosis that is characterized by increased blood flow and/or vascular resistance in the portal system, causing the appearance of a hyperdynamic collateral circulation. Partial portal vein ligation is an experimental model used in rats to study the pathophysiological mechanisms involved in pre-hepatic portal hypertension. Estrogen E2 is an antioxidant molecule with various physiological actions. OBJECTIVES: To evaluate the antioxidant activity of endogenous estrogen in an experimental model of partial portal vein ligation by comparing intact with castrated rats. METHODS: Twenty Wistar rats, weighing on average 250 g were used and divided into four groups: sham-operated (SO; intact (I with partial portal vein ligation (I + PPVL, castrated (C and castrated with partial ligation of the vein (C + PPVL. Day 1: castration or sham-operation; day 7, PPVL surgery; on day 15 post-PPVL, portal pressure in the mesenteric vein of rats was measured on polygraph Letica. Lipid peroxidation in the stomach was assessed using the technique of thiobarbituric acid reactive substances and activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. Statistical analysis was done with ANOVA - Student-Newman-Keuls (mean ± SE, and P<0.05 was considered as significant. RESULTS: Portal pressure was significantly increased in C + PPVL as compared to the other groups. There was no significant difference in the group of intact rats. TBARS showed significant damage in C and C + PPVL in relation to others. Antioxidant enzymes were significantly increased in the castrated rats with subsequent PPVL as compared to the other groups. CONCLUSION: We suggest that estrogen E2 plays a protective role in intact compared with castrated rats because it presents hydrophenolic radicals in its molecule, thus acting as an antioxidant in this experimental model.

  11. Combining experimental and simulation data of molecular processes via augmented Markov models.

    Science.gov (United States)

    Olsson, Simon; Wu, Hao; Paul, Fabian; Clementi, Cecilia; Noé, Frank

    2017-08-01

    Accurate mechanistic description of structural changes in biomolecules is an increasingly important topic in structural and chemical biology. Markov models have emerged as a powerful way to approximate the molecular kinetics of large biomolecules while keeping full structural resolution in a divide-and-conquer fashion. However, the accuracy of these models is limited by that of the force fields used to generate the underlying molecular dynamics (MD) simulation data. Whereas the quality of classical MD force fields has improved significantly in recent years, remaining errors in the Boltzmann weights are still on the order of a few [Formula: see text], which may lead to significant discrepancies when comparing to experimentally measured rates or state populations. Here we take the view that simulations using a sufficiently good force-field sample conformations that are valid but have inaccurate weights, yet these weights may be made accurate by incorporating experimental data a posteriori. To do so, we propose augmented Markov models (AMMs), an approach that combines concepts from probability theory and information theory to consistently treat systematic force-field error and statistical errors in simulation and experiment. Our results demonstrate that AMMs can reconcile conflicting results for protein mechanisms obtained by different force fields and correct for a wide range of stationary and dynamical observables even when only equilibrium measurements are incorporated into the estimation process. This approach constitutes a unique avenue to combine experiment and computation into integrative models of biomolecular structure and dynamics.

  12. Structure and property relationships of amorphous CN sub x a joint experimental and theoretical study

    CERN Document Server

    Santos, M C D

    2000-01-01

    Amorphous CN sub x and CN sub x :H have been prepared by the ion beam assisted deposition technique. Samples were characterized through X-ray and UV photoemission, IR absorption and Raman spectroscopies. These spectra have been interpreted with the aid of quantum chemical calculations based upon the Hartree-Fock theory on several molecular models. The understanding of the electronic and structural properties of the amorphous alloy as a function of nitrogen content could help in the task of synthesizing the metastable silicon-nitride like-phase beta-C sub 3 N sub 4 , a solid which has been predicted to be as hard as diamond. The physical picture emerging from the present study helps to clarify the difficulties in obtaining the crystalline phase of the material, suggesting new experimental directions for syntheses.

  13. Amphoteric trap modeling of multidielectric scaled SONOS nonvolatile memory structures

    Science.gov (United States)

    Libsch, Frank R.; Roy, Anirban; White, Marvin H.

    1987-10-01

    We have characterized multidielectric scaled SONOS nonvolatile memory structures with the quasi-static linear voltage ramp (LVR) technique and dynamic pulse measurements. We have formulated physically-based ERASE/WRITE and retention methods with deep level amphoteric traps which capture and emit carriers to the bands in the silicon nitride film. Amphoteric trap parameters are extracted by the LVR technique. ERASE/WRITE and retention amphoteric trap model simulations agree well with the experimental dynamic pulse measurements. Experimental scaled SONOS structures have been fabricated with tunnel oxide XOT=20 Å, nitride XN=30 Å and blocking oxide XOB=55 Å and demonstrated a static flatband shift of 3.6 V with ±5 V programming voltages. These structures may be used as the nonvolatile memory element in high density VLSI circuits.

  14. Local structure refinement of disordered material models: ion pairing and structure in YCl3 aqueous solutions.

    Science.gov (United States)

    Bowron, D T; Diaz-Moreno, S

    2007-10-04

    Hydrogen/deuterium isotopic neutron diffraction techniques have been used to investigate the structure of a 1 m aqueous solution of YCl3 at room temperature. Empirical potential structure refinement (EPSR) has been used to build a three-dimensional model of the solution structure that is consistent with the bulk solvent correlations strongly probed by the neutron scattering technique. Optimization of the local structural environment of the Y3+ ion sites within the model has been performed through calculations of the yttrium K-edge, extended X-ray absorption fine structure (EXAFS) spectrum of the solution, and detailed information has been extracted on the structure of the ion hydration shell and the extent of inner-sphere ion pairing within the solution. The results demonstrate the significant potential of this hybrid data analysis approach to circumvent the limitations of the individual experimental methods, to refine atomic potential models, and to produce accurate, quantitative structural models of the local environment of dilute atomic species within tightly constrained bulk network structures.

  15. Antibody structural modeling with prediction of immunoglobulin structure (PIGS)

    DEFF Research Database (Denmark)

    Marcatili, Paolo; Olimpieri, Pier Paolo; Chailyan, Anna

    2014-01-01

    applications in all of these areas. Over the years, we have developed or collaborated in developing a strategy that enables researchers to predict the 3D structure of antibodies with a very satisfactory accuracy. The strategy is completely automated and extremely fast, requiring only a few minutes (∼10 min...... on average) to build a structural model of an antibody. It is based on the concept of canonical structures of antibody loops and on our understanding of the way light and heavy chains pack together....

  16. Experimental investigation of tearing-instability phenomena for structural materials

    International Nuclear Information System (INIS)

    Vassilaros, M.G.; Gudas, J.P.; Joyce, J.A.

    1982-08-01

    The objective of this investigation was to extend the range of tearing-instability validation experiments utilizing the compact specimen to include high-toughness alloys. J-Integral tests of ASTM A106; ASTM A516, Grade 70; ASTM A533B; HY-80; and HY-130 steels were performed in a variably compliant screw-driven test machine. Results were analyzed with respect to the materials J/sub I/-R curves and various models of T/sub applied/ for the compact specimen. Tearing instability theory was validated for these high-toughess materials. For the cases of highly curved J/sub I/-R curves, it was shown that the actual value of T/sub material/ at the point of instability should be employed rather than the average T/sub material/ value. The T/sub applied/ analysis of Paris and coworkers applied to the compact specimen appears to be nonconservative in predicting the point of instability; whereas, the T/sub applied/ analysis of Ernst and coworkers appears to be accurate, but requires precision beyond that displayed in this program. The generalized Paris analysis applied to the compact specimen and evaluated at maximum load was most consistent in predicting instability. 16 figures, 3 tables

  17. Experimental investigation of tearing-instability phenomena for structural materials

    International Nuclear Information System (INIS)

    Vassilaros, M.G.; Gudas, J.P.; Joyce, J.A.

    1982-04-01

    Objective was to extend the range of tearing instability validation experiments utilizing the compact specimen to include high toughness alloys. J-Integral tests of ASTM A106; ASTM A516, Grade 70; ASTM A533B; HY-80; and HY-130 steels were performed in a variably compliant screw-driven test machine. Results were analyzed with respect to the materials J/sub I/-R curves and various models of T/sub applied/ for the compact specimen. Tearing instability theory was validated for these high toughness materials. For the cases of highly curved J/sub I/-R curves, it was shown that the actual value of T/sub material/ at the point of instability should be employed rather than the average of T/sub material/ value. The T/sub applied/ analysis of Paris and coworkers applied to the compact specimen appears to be nonconservative in predicting the point of instability; whereas, the T/sub applied/ analysis of Ernst and coworkers appears to be accurate, but requires precision beyond that displayed in this program. The generalized Paris analysis applied to the compact specimen and evaluated at maximum load was most consistent in predicting instability. 16 figures, 3 tables

  18. Experimental models of sepsis and septic shock: an overview

    Directory of Open Access Journals (Sweden)

    Garrido Alejandra G.

    2004-01-01

    Full Text Available Sepsis remains a major cause of morbidity and mortality in surgical patients and trauma victims, mainly due to sepsis-induced multiple organ dysfunction. In contrast to preclinical studies, most clinical trials of promising new treatment strategies for sepsis have fails to demonstrate efficacy. Although many reasons could account for this discrepancy, the misinterpretation of preclinical data obtained from experimental studies, and especially the use of animal models that do not adequately mimic human sepsis may have been contributing factors. In this review, the benefits and limitations of various animal models of sepsis are discussed to clarify the extend to which findings are relevant to human sepsis, particularly with respect to the subsequent design and execution of clinical trials. Such models include intravascular infusion of endotoxin or live bacteria, bacterial peritonitis, cecal ligation and perforation, soft tissue infection, pneumonia or meningitis models, using different animal species including rats, mice, rabbits, dogs, pigs, sheep and nonhuman primates. Despite several limitations, animal models remain essential in the development of all new therapies for sepsis and septic shock, because they provide fundamental information about the pharmacokinetics, toxicity, and mechanism of drug action that cannot be duplicated by other methods. New therapeutic agents should be studies in infection models, even after the initiation of the septic process. Furthermore, debility conditions need to be reproduced to avoid the exclusive use of healthy animals, which often do not represent the human septic patient.

  19. Experimental animal model for late postradiation reaction of the colon

    International Nuclear Information System (INIS)

    Trott, K.R.

    1987-01-01

    Experimental animal model worked out in Muenchen is discussed in which late postradiation reaction in Wistar rats following local irradiation of the colon manifests itself by appearance of colonic stenoses causing death of the animal. Clinical symptoms of this reaction together with results of histopathologic examination of the excised parts of the colon localized in the irradiated area are discussed. The relationships effect-dose obtained in this system for X radiation applying different regimen of dose fractionation and different total times of irradiation are presented. 8 refs., 5 figs., 1 tab. (author)

  20. Modelling N2O dynamics in the engineered N cycle: Evaluation of alternate model structures

    DEFF Research Database (Denmark)

    Smets, Barth F.; Pellicer i Nàcher, Carles; Domingo Felez, Carlos

    2014-01-01

    to minimize the carbon footprint of wastewater treatment plants. The present contribution aims to summarize the recent developments in this field and makes use of standard indentifiability measures to show how the choice of experimental protocols and model structures can potentially impact their calibration....