Academic literature on the topic 'Quasi-Physical Methods'
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Journal articles on the topic "Quasi-Physical Methods":
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Önen, Onursal. "Dispersion and Sensitivity Analysis of Quasi-Scholte Wave Liquid Sensing by Analytical Methods." Journal of Sensors 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/9876076.
Abstract:
Ultrasonic-guided wave sensing relies on perturbation of wave propagation by changing physical properties of the target media. Solid waveguides, through which guided waves can be transduced between the transducer and the target media, are frequently employed for liquid sensing and several other applications. In this manuscript, liquid sensing sensitivity of dispersive quasi-Scholte waves, which are guided interface waves that travel at the solid-liquid boundary, is investigated. Dispersion analysis of quasi-Scholte waves is done and sensitivities of quasi-Scholte waves to changes in fluid density and speed of sound in a dipstick configuration are analyzed. An experimentally verified analytical model based on a global matrix approach is employed in a nondimensional manner to generate representative dispersion and sensitivity surfaces. Optimum configurations with respect to the material properties of the liquid and of the waveguide are illustrated, which would enable optimal quasi-Scholte liquid sensing.
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Davis, Kyle, Miriam Schulte, and Benjamin Uekermann. "Enhancing Quasi-Newton Acceleration for Fluid-Structure Interaction." Mathematical and Computational Applications 27, no. 3 (May 6, 2022): 40. http://dx.doi.org/10.3390/mca27030040.
Abstract:
We propose two enhancements of quasi-Newton methods used to accelerate coupling iterations for partitioned fluid-structure interaction. Quasi-Newton methods have been established as flexible, yet robust, efficient and accurate coupling methods of multi-physics simulations in general. The coupling library preCICE provides several variants, the so-called IQN-ILS method being the most commonly used. It uses input and output differences of the coupled solvers collected in previous iterations and time steps to approximate Newton iterations. To make quasi-Newton methods both applicable for parallel coupling (where these differences contain data from different physical fields) and to provide a robust approach for re-using information, a combination of information filtering and scaling for the different physical fields is typically required. This leads to good convergence, but increases the cost per iteration. We propose two new approaches—pre-scaling weight monitoring and a new, so-called QR3 filter, to substantially improve runtime while not affecting convergence quality. We evaluate these for a variety of fluid-structure interaction examples. Results show that we achieve drastic speedups for the pure quasi-Newton update steps. In the future, we intend to apply the methods also to volume-coupled scenarios, where these gains can be decisive for the feasibility of the coupling approach.
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Gorbunova, Natalya V., and Rimma R. Globenko. "Improving the Organization of Quasi-Professional Activities of Masters of Adaptive Physical Education as a Guarantee of Increasing Professional Competence." Journal of Pedagogical Innovations, no. 2 (June 3, 2024): 60–69. http://dx.doi.org/10.15293/1812-9463.2402.06.
Abstract:
Introduction. The article discusses the problem: what are the effective forms and methods of work of developing professional competence among masters of the department of physical education in the field of training “Physical education for persons with health problems (adaptive physical education)” of the Sevastopol Institute of Economics and Humanities (branch) of the Crimean Federal University named after V. I. Vernadsky. The purpose of the study is to substantiate the importance of organizational and methodological improvement of the quasi-professional sector of the educational process. Methodology. Using scientific methods of pedagogical observation, questioning, studying the products of pedagogical activity and pedagogical documents, the authors substantiate the role of inclusive competence as an integral part of professional competence, as well as the possibility of its optimal improvement at the quasi-professional stage of the educational process using special pedagogical technologies and methods, including conducting sociocultural inclusive events. Results. It was revealed that masters of the Faculty of Physical Culture have, in general, sufficient and strong theoretical knowledge in the field of inclusion. At the same time, masters who carried out educational activities in traditional forms and in standard organizational and methodological conditions demonstrated unstable, weak skills in applied, practical activities related to inclusive competence. Conclusions. The main reserves for increasing the inclusive competence of master of physical education lie in the quasi-professional sector of the educational process, and the task of increasing the level of inclusive competence of master of physical education, and therefore increasing their overall professional level, can be solved by intensifying and optimizing educational and applied activities at the quasi-professional stage formation of inclusive competence.
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Murphy, Paula, Tim Persoons, Seamus O’Shaughnessy, and Darina Murray. "A comparison of postprocessing methods for hot film sensors for the heat transfer analysis of impinging jet flows." Journal of Physics: Conference Series 2116, no. 1 (November 1, 2021): 012043. http://dx.doi.org/10.1088/1742-6596/2116/1/012043.
Abstract:
Abstract The aim of this investigation is to optimise the data post-processing techniques associated with hot film sensors when intended to be used as a means of accurate, high-resolution heat flux measurement. More specifically, this project focuses on the performance of hot film sensors operated in a constant temperature anemometer bridge, used in conjunction with impinging jet air flows. The characteristic heat transfer behaviour in this impinging jet flow provides the reference against which the heat flux data attained using the hot film sensor is compared. As part of this investigation, three hot film calibration methods are examined for a range of sensor overheat values: (A) a wall shear correction method, (B) a physical quasi 1-D conduction model and (C) a physical quasi 2-D fin conduction model. The results show that the method C, when used in conjunction with a 5 K sensor overheat, best replicated that of the reference heat flux sensor for the jet configurations investigated.
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Fedotov, M. Yu. "METHODS FOR THE FORMATION OF SPATIAL TOPOLOGY AND INTERROGATION OF FIBER-OPTIC SENSORS FOR DIAGNOSTICS OF COMPOSITE STRUCTURES (Review)." Kontrol'. Diagnostika, no. 298 (April 2023): 24–37. http://dx.doi.org/10.14489/td.2023.04.pp.024-037.
Abstract:
The paper formulates general requirements for the formation of spatial topologies of quasi-distributed fiber-optic systems of embedded monitoring based on fiber Bragg gratings for monolithic and three-layer structures made of polymer composite materials. The main types of spatial topologies of fiber-optic sensors for the implementation of an effective quasi-distributed system of embedded diagnostics of composite structures are considered. The main methods for interrogating arrays of fiber-optic sensors that form a quasi-distributed system of embedded diagnostics of composite structures are analyzed, an overview and analysis of the technical characteristics of foreign and domestic interrogation equipment is given. It has been established that for practical applications, taking into account the relative simplicity of physical implementation and the availability of interrogation equipment, it is advisable to use a mixed topology of fiber-optic sensors, which includes elements of serial and star topologies, with he spectral channel separation method being the most optimal.
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Sil'chenko, Ol'ga, Marina Siluyanova, and Petr Hopin. "STRENGTH PROPERTIES INVESTIGATION OF COMPOSITE COATINGS WITH QUASI-CRYSTALS OBTAINED THROUGH METHODS OF GAS DYNAMIC SPUTTERING." Bulletin of Bryansk state technical university 2020, no. 12 (December 1, 2020): 11–18. http://dx.doi.org/10.30987/1999-8775-2020-12-11-18.
Abstract:
The work purpose is to investigate strength properties of composite coatings with quasi-crystals obtained through the method of gas dynamic sputtering.
The object of development: quasi-crystals based on titanium carbonitride clad with nickel. In the course of the work there is offered a method for investigations of coating strength based on a pin and adhesive method with composites based on titanium carbonitride.
The novelty of this investigation consists in obtaining new materials and investigations of their physical-mechanical properties.
Composite coating on the basis of titanium carbonitride has shown high separation properties. The destruction took place in an intermediate layer between VN20 and KNTP35.
During 10 mm bending there is a fine even mesh. At the impact load made there were not observed chips and separations that allow using coating data in heavy-loaded parts.
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Zul Fadli Rambe, Ahmad, Phil Yanuar Kiram, Arsil Arsil, Ridho Bahtra, and Yovhandra Ockta. "Improvement of basic soccer techniques with training methods and physical condition." Jurnal SPORTIF : Jurnal Penelitian Pembelajaran 10, no. 1 (April 23, 2024): 76–89. http://dx.doi.org/10.29407/js_unpgri.v10i1.21575.
Abstract:
This study aims to investigate the effect of small-sided games and rondo training methods, as well as physical conditions, on the basic technique skills of passing, controlling, and dribbling soccer players. This research mode is a Quasi-Experiment with a factorial research design. The sample consisted of 38 child soccer athletes aged 10-12 years from the Wijaya men's soccer team, with purposive sampling from young soccer players (10-12 years) from the Wijaya men's soccer team in Padang. Skill measurements are performed with bounce board instruments for passing control, dribbling tests, agility tests (Illinois Agility Run Test), and speed tests (30-meter run) to measure physical condition. Data analysis using a two-track ANOVA test with a significance level of α 0.05. The results showed that there was a significant difference in the effect of the Small-Sided Games and Rondo methods on passing control (F = 5.931, p = 0.025 < 0.05) and dribbling (F = 61.588, p = 0.000 < 0.05) soccer players. In addition, there is a difference between high and low physical conditions for passing control and dribbling (α < 0.05). Furthermore, there was a significant interaction between training methods and physical condition on passing control (F = 9.481, p = 0.007 < 0.05) and dribbling (F = 88.817, p = 0.000 < 0.05). This study concluded that small-sided games, rondo training methods, and physical conditions have a significant effect on the basic skills of soccer players.
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Sabchevski, S., I. Zhelyazkov, E. Benova, V. Atanassov, P. Dankov, M. Thumm, A. Arnold, J. Jin, and T. Rzesnicki. "Quasi-optical converters for high-power gyrotrons: a brief review of physical models, numerical methods and computer codes." Journal of Physics: Conference Series 44 (July 1, 2006): 102–9. http://dx.doi.org/10.1088/1742-6596/44/1/012.
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dos Santos Azevedo, Juarez, and Saulo Pomponet Oliveira. "A Numerical Comparison Between Quasi-Monte Carlo and Sparse Grid Stochastic Collocation Methods." Communications in Computational Physics 12, no. 4 (October 2012): 1051–69. http://dx.doi.org/10.4208/cicp.260111.230911a.
Abstract:
AbstractQuasi-Monte Carlo methods and stochastic collocation methods based on sparse grids have become popular with solving stochastic partial differential equations. These methods use deterministic points for multi-dimensional integration or interpolation without suffering from the curse of dimensionality. It is not evident which method is best, specially on random models of physical phenomena. We numerically study the error of quasi-Monte Carlo and sparse grid methods in the context of ground-water flow in heterogeneous media. In particular, we consider the dependence of the variance error on the stochastic dimension and the number of samples/collocation points for steady flow problems in which the hydraulic conductivity is a lognormal process. The suitability of each technique is identified in terms of computational cost and error tolerance.
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Nkwocha, Francis Kehinde, and Wasiu Owolabi. "Demonstration Methods in Primary Schools: A Study of Academic Achievement in Physical and Health Education." Journal of Innovation and Research in Primary Education 2, no. 1 (June 30, 2023): 7–13. http://dx.doi.org/10.56916/jirpe.v2i1.408.
Abstract:
This research aimed to investigate how the demonstration method influences the academic performance of primary school students in physical and health education in Kwara State, Nigeria. The study followed a quasi-experimental design, involving 79 pupils from two public primary schools. The research utilized the 'Physical and Health Education Achievement Test (PHEAT)' as the assessment tool, which was carefully validated and tested for its reliability, showing a reliability index of 0.76 using the test-retest method. Two hypotheses were formulated and examined using Analysis of Covariance (ANCOVA). The results of the study revealed a significant positive impact of the demonstration method on pupils' academic achievement in Physical and Health Education. However, when considering gender as a factor, the interaction between treatment and gender did not show a significant effect on pupils' academic achievement in the same subject. In conclusion, the findings suggest that using the demonstration method can enhance the academic achievement of primary school pupils in physical and health education, irrespective of their gender. Based on these results, it is recommended that teachers receive training in utilizing the demonstration method while teaching Physical and Health Education.
Dissertations / Theses on the topic "Quasi-Physical Methods":
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Gamot, Juliette. "Algorithms for Conditional Search Space Optimal Layout Problems." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILB042.
Abstract:
Cette thèse s'inscrit dans le cadre de l'optimisation d'agencement, une étape importante dans la conception de systèmes multidisciplinaires complexes tels que les véhicules aérospatiaux. Les problèmes d'agencement optimal (OLP) consistent à trouver la meilleure disposition d'un ensemble de composants dans un système ou un espace, afin d'atteindre certains objectifs (réduction des coûts, amélioration des performances, etc.) tout en satisfaisant diverses contraintes (géométriques, fonctionnelles, etc.). Le traitement des OLP est encore un défi aujourd'hui, tant en termes de formulation que de résolution. En effet, les OLP sont souvent très contraints et impliquent de nombreuses variables de décision (continues, discrètes, catégorielles), qui peuvent être fixes ou conditionnelles. Les variables conditionnelles sont utiles pour définir différents choix de conception qui doivent être faits en même temps que l'optimisation de l'agencement des composants. Ainsi, la résolution des OLP nécessite l'utilisation d'algorithmes d'optimisation avancés combinant différentes catégories de méthodes, comme par exemple les métaheuristiques et l'optimisation bayésienne.L'objectif global de la thèse est d'étudier les OLP, leur formulation dans différents contextes, leur résolution à l'aide de diverses méthodes d'optimisation et hybridations, ainsi que la validation de ces méthodes dans le cadre de la conception de véhicules aérospatiaux. Les contributions de la thèse sont organisées en deux parties correspondant à deux types d'OLP. Dans la première (respectivement deuxième) partie, la liste de composants à agencer est fixe (resp. variable), impliquant des OLP à espace de recherche fixe ou FSS-OLP, (resp. des OLP à espace de recherche conditionnel ou CSS-OLP). Dans les deux cas, le système/l'espace dans lequel les composants sont agencés est considéré comme mono ou multi-contenant.Dans la première partie, une étude des FSS-OLP est proposée, incluant leurs formulations génériques, leurs applications et méthodes de résolution, avec un focus particulier sur les méthodes quasi-physiques et les métaheuristiques. Basés sur un système de force virtuelle (VF), les algorithmes quasi-physiques simulent les lois de la dynamique et traitent efficacement les problèmes fortement contraints. Une variante (nommée CSO-VF) de de ces algorithmes est développée afin de résoudre les FSS-OLP à un seul contenant. Dans CSO-VF, la position et l'orientation des composants évoluent grâce au VF. Pour traiter les systèmes multi-contenants, CSO-VF est hybridé à un algorithme génétique (GA) dans un algorithme à deux étages qui affecte les composants aux contenants puis optimise leur disposition dans chacun des contenants. Ces deux algorithmes sont évalués grâce à des problèmes d'agencement de satellites.Dans la deuxième partie, une étude des CSS-OLP est proposée avec la même approche que dans la première partie. Les variables conditionnelles engendrent des OLP plus complexes. Par exemple, dans le contexte de la conception aérospatiale, une quantité donnée de carburant peut être incluse dans le système, soit dans un grand réservoir, soit dans deux plus petits. Par conséquent, le nombre de composants à positionner n'est pas le même dans les deux cas et le nombre de variables de conception et de contraintes varie donc au cours du processus d'optimisation. Deux approches ont été développées pour traiter les CSS-OLP à un seul contenant : la première est un GA modifié pour introduire des variables cachées dans les chromosomes. La seconde est une approche bi-niveaux combinant optimisation bayésienne et l'algorithme CSO-VF. L'optimisation bayésienne sélectionne les composants et CSO-VF optimise leur agencement. Cette dernière approche a été hybridée avec un GA dans un algorithme tri-niveaux afin de traiter les CSS-OLP multi-contenants. Enfin, tous les algorithmes sont évalués et comparés grâce à des problèmes d'agencement de satellitesThis thesis falls within the scope of layout optimization, which is an important stage in the design of complex multidisciplinary engineering systems such as aerospace vehicles. Optimal layout problems (OLPs) involve finding the best arrangement of a set of components within a single- or multi-container system or space to meet specific objectives (cost reduction, performance enhancement, etc.) while satisfying various constraints (geometrical, functional, etc.). Dealing with OLPs is challenging both in terms of their formulation and their efficient and effective resolution. Actually, OLPs are often highly constrained and involve many mixed decision variables (continuous, discrete/categorial) which may be fixed or conditional. Conditional variables are highly useful to define different design choices when the set of components to be arranged is variable and dynamic. Consequently, their resolution requires the use of advanced optimization algorithms combining different classes of (mixed-variable) methods including metaheuristics and Bayesian optimization.The overall objective of the thesis is to investigate OLPs, their formulation in different contexts, their resolution using various optimization methods and their hybridization, and their validation within the framework of aerospace vehicle design. The contributions of the thesis are organized in two parts corresponding to two types of OLPs. In the first (resp. second) part, the set of components to be arranged is fixed (variable or conditional) involving fixed search space OLPs or FSS-OLPs (resp. conditional search space OLPs or CSS-OLPs). In both cases, the system/space in which the components are arranged is considered single- or multi-container.In the first part, a survey of constrained mixed-variable FSS-OLPs is proposed including their generic formulations, applications and resolution methods with a particular focus on quasi-physical methods and population-based metaheuristics. Based on a virtual force system (VF) quasi-physical algorithms emulate the principle of physical laws in system dynamics and deal efficiently with highly constrained problems. A variant (namely CSO-VF) of these algorithms is devised for solving single-container FSS-OLPs. In CSO-VF, the positions and orientations of the components are evolved using VF. To deal with multi-container systems, CSO-VF is combined with a Genetic Algorithm (GA) in a two-stage algorithm that assigns the components to the containers and optimizes their layout. These single- and multi-container algorithms are assessed considering satellite module FSS-OLPs that are representative benchmarks.In the second part, a survey of constrained mixed-variable CSS-OLPs is proposed in the same way than in the first part. Conditional variables involve more complex OLPs. Actually, for instance, in the context of aerospace concept design, a given amount of fuel could be included in a container in either one large tank or two smaller ones. Therefore, as the number of components to position is not the same in both cases the number of design variables as well as constraint functions vary during the optimization process. To deal with single-container CSS-OLPs, two approaches have been investigated: the first one is a GA revisited considering hidden variables, leading to variable-geometry OLPs (in objective and constraint functions). The second approach is a two-stage surrogate guided-CSO-VF algorithm combining Bayesian Optimization with CSO-VF. Bayesian Optimization selects the components with are considered by CSO-VF for layout optimization. This latter approach has been extended with a GA in a three-stage algorithm to tackle multi-container CSS-OLPs. Finally, all the algorithms are evaluated and compared based on their application to CSS variants of satellite module OLPs
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Ye, Zhen. "Using TPR Method in Teaching English Adjectives." Thesis, Högskolan Kristianstad, Sektionen för lärande och miljö, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-8744.
Abstract:
The topic of this study is using Total Physical Response (TPR) in teaching English adjectives to 11-year-old pupils. The objective of this study is to investigate whether the TPR method is effective in teaching English adjectives. The researcher used a quasi-experiment to design this study. The population was the pupils aged 11 in a middle school in Kristianstad. 30 pupils were selected as samples and divided into two groups: one experimental group and one control group. The steps of this experiment were: (1) the experimental group was taught by the TPR method; (2) the control group and the experimental group were given the same post-test. In order to investigate whether there is a necessity to adopt new English vocabulary teaching technique for these pupils, two questionnaires were deliberated; the first questionnaire was for all testees and the second questionnaire was just for the experimental group. The result of the study showed the pupils’ achievements in the experimental group were improved by the TPR method. The mean score of the experimental group was much higher than that of the control group. The p-value of this test was 0.0002 less than 0.01 which showed strong evidence that the results were not achieved coincidentally. The effect size of this study was 2.59 more than 0.8 which indicated that the TPR method has significant effectiveness in teaching English adjectives. The questionnaires indicated that TPR was the new English vocabulary teaching technique that the pupils need.
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Král, Petr. "Verifikace nelineárních materiálových modelů betonu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227601.
Abstract:
Diploma thesis is focused on the description of the parameters of nonlinear material models of concrete, which are implemented in a computational system LS-DYNA, interacting with performance of nonlinear test calculations in system LS-DYNA on selected problems, which are formed mainly by simulations of tests of mechanical and physical properties of concrete in uniaxial compressive and tensile on cylinders with applying different boundary conditions and by simulation of bending slab, with subsequent comparison of some results of test calculations with results of the experiment. The thesis includes creation of appropriate geometric models of selected problems, meshing of these geometric models, description of parameters and application of nonlinear material models of concrete on selected problems, application of loads and boundary conditions on selected problems and performance of nonlinear calculations in a computational system LS-DYNA. Evaluation of results is made on the basis of stress-strain diagrams and load-displacement diagrams based on nonlinear calculations taking into account strain rate effects and on the basis of hysteresis curves based on nonlinear calculations in case of application of cyclic loading on selected problems. Verification of nonlinear material models of concrete is made on the basis of comparison of some results of test calculations with results obtained from the experiment.
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張啟聖. "A study of physical characteristics of chicken eggshell of local breeds by a quasi-static compression method." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/86150096121108128069.
Book chapters on the topic "Quasi-Physical Methods":
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Creech, Calvin, Erik Mosselman, Jean-Michel Hiver, and Nils Huber. "Sustainable Management of the Navigability of Natural Rivers (PIANC WG 236)." In Lecture Notes in Civil Engineering, 232–42. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_21.
Abstract:
AbstractThe PIANC InCom/EnviCom Working Group 236 was established in early 2021 to develop PIANC guidelines for improving navigability conditions on natural or quasi-natural rivers, while maintaining morphological processes and natural river form and function. Its key objectives include: 1) development of guidelines to improve and maintain the navigability in natural rivers; 2) assess the sustainability of river training works designed to improve the navigability; 3) assess the sustainability of dynamic river management (monitoring and shifting of navigation aids to adapt the navigation channel to the river dynamics); 4) highlight the technical, operational, economic and environmental considerations for navigation in natural rivers compared to that in regulated rivers and canals; and 5) improve the understanding of the physical processes in natural rivers, developed with or without river training works. The developed guidance includes a planning framework for developing a navigability improvement masterplan for a natural or quasi-natural river system, and the integrated and adaptive management strategies that can be applied at a system scale. Specific interventions and measures have been identified to meet the dual goals of maintaining morphological river function and improving navigability conditions. These measures include dynamic charting; morphological dredging and disposal management; Temporary, Adaptable, and Flexible Training Structures (TAFTS); riverbed armoring and sediment nourishment; rock excavation; meander cutoffs and oxbow development; localized traditional river training structures; and channel closure structures. The impacts and strategies for mitigation associated with some of the measures are analyzed and discussed. Finally, the continual monitoring, management, and operational tools available for improving navigability in a morphologically active river system is presented. It is recognized that natural and quasi-natural rivers will typically be more fluvially active and dynamic than systems that have used traditional methods for navigability improvements including heavily trained rivers or systems with locks and dams. These unrestricted and unconfined river systems, therefore, will require new and innovative strategies to monitor the fluvial and geomorphic changes of the system in order to inform managers and navigators of the river. Case studies are presented that include the Madeira River (Brazil); Magdalena River (Colombia); Niger Delta (Nigeria); Yangtze River (China); the Brahmaputra-Jamuna River (India); and the Red River (Vietnam).
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Marvuglia, Antonino, and Mohamed Laib. "Exploratory Analysis of Building Stock: A Case Study for the City of Esch-sur-Alzette (Luxembourg)." In Computational Science and Its Applications – ICCSA 2023 Workshops, 374–91. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-37105-9_25.
Abstract:
AbstractOne of the main steps in developing urban building energy models (UBEM) is the classification of the building stock according to building archetypes. Different approaches have been proposed to accomplish this task, some based on the application of clustering techniques, or a combination of expert knowledge, deterministic classification, and data driven approaches. This paper proposes the utilization of a hybrid approach where exploratory data analysis is combined with feature extraction and feature selection to support clustering. The proposed methodology was applied to the building stock of the city of Esch-sur-Alzette (Grand Duchy of Luxembourg). The used data set includes buildings’ geometrical and physical characteristics, preassigned occupancy estimates, and final energy use simulated with a quasi-steady-state model. According to the variables’ combination and deterministic building stock fragmentation schemes used, the number of archetypes identified varied between 12 and 89. The paper shows the potential of clustering techniques for the development of archetypes, even though this must be combined with other (deterministic) fragmentation methods because clustering alone does not allow for the differentiation of building use typologies and construction periods, both of which must be considered to characterize buildings properly.
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Diestmann, Thomas, Nils Broedling, Benedict Götz, and Tobias Melz. "Surrogate Model-Based Uncertainty Quantification for a Helical Gear Pair." In Lecture Notes in Mechanical Engineering, 191–207. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77256-7_16.
Abstract:
AbstractCompetitive industrial transmission systems must perform most efficiently with reference to complex requirements and conflicting key performance indicators. This design challenge translates into a high-dimensional multi-objective optimization problem that requires complex algorithms and evaluation of computationally expensive simulations to predict physical system behavior and design robustness. Crucial for the design decision-making process is the characterization, ranking, and quantification of relevant sources of uncertainties. However, due to the strict time limits of product development loops, the overall computational burden of uncertainty quantification (UQ) may even drive state-of-the-art parallel computing resources to their limits. Efficient machine learning (ML) tools and techniques emphasizing high-fidelity simulation data-driven training will play a fundamental role in enabling UQ in the early-stage development phase.This investigation surveys UQ methods with a focus on noise, vibration, and harshness (NVH) characteristics of transmission systems. Quasi-static 3D contact dynamic simulations are performed to evaluate the static transmission error (TE) of meshing gear pairs under different loading and boundary conditions. TE indicates NVH excitation and is typically used as an objective function in the early-stage design process. The limited system size allows large-scale design of experiments (DoE) and enables numerical studies of various UQ sampling and modeling techniques where the design parameters are treated as random variables associated with tolerances from manufacturing and assembly processes. The model accuracy of generalized polynomial chaos expansion (gPC) and Gaussian process regression (GPR) is evaluated and compared. The results of the methods are discussed to conclude efficient and scalable solution procedures for robust design optimization.
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Viba, Janis, Vitaly Beresnevich, and Martins Irbe. "Methods and Devices for Wind Energy Conversion." In Wind Turbines - Advances and Challenges in Design, Manufacture and Operation [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103120.
Abstract:
The chapter deals with the analysis and optimization of the operational safety and efficiency of wind energy conversion equipment. The newly proposed method of wind energy conversion involves flat blades or space prisms that perform translation motion due to the interaction with air flow. Air flow interactions with 2D moving prisms (convex, concave) are studied by computer simulation. Optimization of prism shape is made using as criteria maximum of generating force and power. Theoretical results obtained are used in the designing of new devices for energy extraction from airflow. Models of wind energy conversion devices equipped with one vibrating blade are developed (quasi translatory blade’s motion model; model with vibrating blade equipped with crank mechanism). The operation of the system due to the action of air flow is simulated with computer programs. Possibilities to obtain energy with generators of different characteristics, using mechatronic control, have been studied. The effect of wind flow with a constant speed and also with a harmonic or polyharmonic component is considered. Partial parametric optimization of the electromechanical system has been performed. The serviceability and main advantages of the proposed methods and devices are confirmed by experiments with physical models in a wind tunnel.
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"Nonlinear quasi-geostrophic models." In Inverse Methods in Physical Oceanography, 181–202. Cambridge University Press, 1992. http://dx.doi.org/10.1017/cbo9780511600807.008.
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"Open-ocean modelling: quasi-geostrophy." In Inverse Methods in Physical Oceanography, 203–56. Cambridge University Press, 1992. http://dx.doi.org/10.1017/cbo9780511600807.009.
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Ferreirós, José. "Advanced Math." In Mathematical Knowledge and the Interplay of Practices. Princeton University Press, 2015. http://dx.doi.org/10.23943/princeton/9780691167510.003.0006.
Abstract:
This chapter proposes the idea that advanced mathematics is based on hypotheses—that far from being a priori, it is based on hypothetical assumptions. The concept of quasi-empiricism is often linked with the view that inductive methods are at play when the hypotheses are established. The presence of hypotheses at the very heart of mathematics establishes an important similitude with physical theory and undermines the simple distinction between “formal” and “empirical” sciences. The chapter first elaborates on a hypothetical conception of mathematics before discussing the ideas (and ideals) of certainty and objectivity in mathematics. It then considers the modern problems of the continuum that exist in ancient Greek geometry, along with the so-called methodological platonism of modern mathematics and its focus on mathematical objects. Finally, it describes the Axiom of Completeness and the Riemann Hypothesis.
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Netzer, Falko P., and Claudine Noguera. "Two-dimensional oxides." In Oxide Thin Films and Nanostructures, 127–65. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198834618.003.0005.
Abstract:
The novel physical and chemical properties and functionalities of two-dimensional (2-D) oxide materials are assessed. The synthesis of one unit-cell thick 2-D oxides poses particular challenges, since in contrast to other 2-D materials, which can be fabricated by exfoliation of layered bulk compounds, the majority of oxides do not occur in layered bulk structures. Most 2-D oxides are therefore prepared by thin-film deposition methods on substrates. However the fabrication of free-standing quasi-2-D oxide nanosheets, with less restrictive several monolayer thickness, has been successfully achieved by wet chemical procedures. New geometry concepts and electronic properties are observed in 2-D oxides, due to quantum confinement and interface proximity effects. Atomic geometries, electronic structure, ferroic properties and catalytic behaviour of 2-D oxides are discussed, together with promising prototypical proof-of-concept experiments for prospective applications. The edge states in oxide nanoribbons, 2-D objects of limited width, and their polarity aspects are discussed.
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Dixon, J. M., J. A. Tuszynski, and P. A. Clarkson. "Conclusions." In From Nonlinearity to Coherence, 554–57. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780198539728.003.0008.
Abstract:
Abstract The motivation for this book was to emphasize the importance of nonlinearity in many-body systems, especially in condensed-matter physics. This approach is based on the belief that interactions between particles play a dominant role in solid state phenomena and that the constituent particles, in most cases, may not be treated as nearly independent entities. While the introduction of quasi-particles, representing collective modes of behaviour of the solid, goes a long way towards understanding the physics of such systems, there are always limitations to this approach. The first limitation is the stability of the underlying structure, e.g. the crystal lattice, which cannot be recovered using independent particle approaches. A related limitation is that, in most cases, collective modes interact, which may lead to the emergence of localized excitation modes that cannot be derived from a perturbative approach. Our strategy or philosophy, therefore, has been to complement the traditional methods of linearizing physical problems and instead explore new possibilities that nonlinear physics affords.
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Luo, Xian Fan, Kien Tsong Chau, Siti Nazleen Abdul Rabu, and Ye Bei. "Investigating the Potential of Integrating 2D Animation and Augment Reality Technology in Promoting Learning Motivation and Achievement on Chaozhou Opera." In Integrating Cutting-Edge Technology Into the Classroom, 184–202. IGI Global, 2024. http://dx.doi.org/10.4018/979-8-3693-3124-8.ch010.
Abstract:
This research aims to explore the impact of the joint application of 2D animation and augmented reality technology on the learning motivation and achievement of third-year college students learning traditional culture courses. AR is a technology that augments a live view of reality with computer-generated sound, images, or video. It allows users to interact with virtual objects in a real physical environment. Therefore, the researchers developed a learning system called “OperaAR-E” for the “Chaozhou Opera Learning” unit. This research adopts a quasi-experimental design with a pre-test and post-test control group, and uses ARCS questionnaires, achievement tests, observation and interview methods for data collection and research. The independent variable of this research is the “OperaAR-E” learning system, and the dependent variables are learning motivation and learning achievement. The researchers hope to use this learning system to inspire young people to learn traditional culture and gain an in-depth understanding of Chaozhou opera, a traditional Chinese opera form.
Conference papers on the topic "Quasi-Physical Methods":
1
Lu, David X., Behrooz K. Shahidi, Cliff M. Rivard, and Rihua Li. "Some Studies for the Application of Explicit FE Codes in Simulation of Quasi-Static Tests." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1192.
Abstract:
Abstract Explicit algorithms have been applied to study quasi-static large deformation contact problems with the use of some non-physical acceleration methods for the improvement of computation efficiency. Numerical errors caused by those non-physical acceleration methods are studied in this paper. It is found that oscillation will be introduced if one uses dynamic approach to study a quasi-static problem. Numerical errors caused by dynamic approach will be increased when non-physical acceleration techniques, such as Speed-Up-Loading and Mass-Scaling, are applied.
2
Porto, Stefano, Anthony Hartin, and Gudrid Moortgat-Pick. "Methods for evaluating physical processes in strong external fields at e+e? colliders: Furry picture and quasi-classical approach." In Proceedings of the Corfu Summer Institute 2012. Trieste, Italy: Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.177.0039.
3
Xu, YiBing, Ruizhe Cao, Lei Gao, Qiujun Wang, Chong Yan, and Ying Piao. "Quasi-steady state CFD simulation method for the ac/deceleration process of gas turbine engine." In GPPS Hong Kong23. GPPS, 2023. http://dx.doi.org/10.33737/gpps23-tc-292.
Abstract:
Acceleration and deceleration characteristics reflect the ability of the engine to switch operating states, which is an important performance parameter of gas turbine engine. The development of computational fluid dynamics (CFD) technology provides a new paradigm for engine simulation and makes it possible to carry out unsteady simulations of gas turbine engine in a more physical way. From the perspective of physical equations, three feasible schemes for simulating the ac/deceleration process are presented and analysed: transient coupled scheme, transient decoupled scheme and quasi-steady state scheme. The difference between the three methods lies in the level of the coupling between the rotor motion equation and N-S equations. The quasi-steady state simulation method can realize rapid simulation of engine transient process by considering rotor motion inertia while ignoring the fluid inertia in the engine. Taking KJ66 micro turbojet as an example, the ac/deceleration process is simulated based on the quasi-steady state CFD simulation. With different ac/deceleration fuel supply rules, the duration time from the idling state to the design state is estimated and the whole engine flow field is obtained. This simulation of the engine ac/deceleration characteristics can provide an important forecasting method for designing the ac/deceleration control rules of the gas turbine engine.
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Gezork, Tobias, and Stefan Völker. "Applicability of Quasi-3D Blade Design Methods to Profile Shape Optimizaton of Turbine Blades." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95467.
Abstract:
The performance of gas turbine airfoils is continually improved by creating advanced aerodynamic and thermal designs. Optimization methods are used to handle the increasing complexity of such a design. However, optimization is expensive when performed based on 3D CFD calculations. Therefore, an optimization strategy based on simpler, less expensive analysis methods is desirable. Oftentimes, a so-called quasi-3D (Q3D) approach is used, where 2D calculations are carried out on multiple, radially stacked meridional blade sections. This paper investigates the applicability of such an approach for optimization with regard to blade profile loss. Obviously, certain physical effects are neglected using this approach, leading to errors in the predicted blade performance. Still, optimization based on Q3D calculations might be possible if the error is consistent, i.e. not random. For this purpose, a design of experiment (DOE) was carried out to compare and correlate loss predictions from Q3D calculations and high-fidelity 3D CFD calculations for gas turbine blades. It is shown that the total pressure loss coefficients found with both the Q3D and 3D calculations correlate well (75–90%) to warrant the use of a Q3D method for profile shape optimization. Subsequently, an optimization is performed to demonstrate the applicability of the method.
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Ibrahim, Zakaria N. "Piping Fluid Transients Made Simple: Part II — Application of the SSFFC Methods." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71788.
Abstract:
Piping systems transporting fluid between plant components are subjected to a variety of anticipated and/or postulated flow changes that disturb their steady state operations. These changes cause the fluid flow to accelerate and/or decelerate. However, consideration of fluid elasticity transforms these disturbances into weak and/or strong propagating sound waves, depending upon the abruptness level of the fluid state change. This generates dynamic forces on the pipe segments of the piping system. A simple concept for understanding the piping fluid transient phenomenon from its physical perspective is presented. The piping system consists of several pipe segments, each segment having a constant cross-sectional flow area. The pipe segment is further divided into a consecutive series of zones. Each zone comprises two or three sub-zones of quasi steady state flow. The sub-zones are separated by interface fronts into which the jump in fluid pressure and velocity occurs across them. These fronts propagate and clash with each other to create the next temporal set of sub-zones quasi steady state flow. This method is denoted in this paper as steady state flow fronts clashing ‘SSFFC’. Clashing between the incident, transmitted and/or reflected wave fronts within the zone are introduced. As a follow-up to the first part of this two-part publication, this paper demonstrates two sample applications of SSFFC method utilizing the proposed wave front bookkeeping technique.
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Hohenberg, Karl G., Peter J. Newton, Ricardo F. Martinez-Botas, Martin Halamek, Kotaro Maeda, and Julien Bouilly. "Development and Experimental Validation of a Low Order Turbine Model Under Highly Pulsating Flow." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63983.
Abstract:
The flow through radial turbines in automotive turbocharging applications is inherently highly unsteady, exhibiting high amplitude pulsations of varying frequencies. This can have a significant effect on the performance of the turbine, and therefore accurate modelling of these effects is key in good engine design, particularly in the realm of 1-D modelling. Assuming that the turbine stage acts in a quasi-steady manner can result in modelling errors. To better capture the physical effects of unsteady flow, a novel 1-D model of a radial turbine volute was developed, within the engine modelling software GT-Power. A meanline model was developed and integrated into the volute model as a means of modelling the rotor, which was assumed to be quasi steady. Experimental work was done to characterise the unsteady performance of the turbine, and the results were used to validate the model. The model showed good agreement with experimental data as well as some small improvements compared to industry standard methods of modelling.
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Huang, Jiacai, YangQuan Chen, and Zhuo Li. "Mathematical Model of Human Operator Using Fractional Calculus for Human-in-the-Loop Control." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-47464.
Abstract:
Mathematical models of human operator play a very important role in the Human-in-the-Loop manual control system. For several decades, modeling human operator’s dynamic has been an active research area. The traditional classical human operator models are usually developed using the Quasi-linear transfer function method, the optimal control theory method, and so on. The human operator models established by the above methods have deficiencies such as complicated and over parameterized, even for basic control elements. In this paper, based on the characteristics of human brain and behaviour, two kinds of fractional order mathematical models for describing human operator behavior are proposed. Through validation and comparison by the actual data, the best_fit model with smallest root mean squared error (RMSE) is obtained, which has simple structure with only few parameters, and each parameter has definite physical meaning.
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Liu, Yujia, Sifan Peng, Nan Gui, Xingtuan Yang, Jiyuan Tu, and Shengyao Jiang. "Experimental Study on Gravity Driven Discharging of Quasi-Two-Dimensional Pebble Bed Based on Mathematical Morphology." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16367.
Abstract:
Abstract The pebbles flow is a fundamental issue for both academic investigation and engineering application in reactor core design and safety analysis. In general, experimental methods including spiral X-ray tomography and refractive index matched scanning technique (RIMS) are applied to obtain the identification of particles’ positions within a three-dimensional pebble bed. However, none of the above methods can perform global bed particles’ position identification in a dynamically discharging pebble bed, and the corresponding experimental equipment is difficult to access due to the complication and high expense. In this research, the experimental study is conducted to observe the gravity driven discharging process in the quasi two-dimensional silos by making use of the high-speed camera and the uniform backlight. A mathematical morphology-based method is applied to the pre-processing of the captured results. After being increased the gray value gradient by the threshold segmentation, the edges of the particles are identified and smoothed by the Sobel algorithm and the morphological opening operation. The particle centroid coordinates are identified according to the Hough circle transformation of the edges. For the whole pebble bed, the self-programmed process has a particle recognition accuracy of more than 99% and a particle centroid position deviation of less than 3%, which can accurately obtain the physical positions of all particles in the entire dynamically discharge process. By analyzing the position evolution of individual particles in consecutive images, velocity field and motion events of particles are observed. The discharging profiles of 5 conditions with different exit are analyzed in this experiment. The results make a contribution to improving the understanding of the mechanism of pebbles flow in nuclear engineering.
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He, L. "An Euler Solution for Unsteady Flows Around Oscillating Blades." In ASME 1989 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1989. http://dx.doi.org/10.1115/89-gt-279.
Abstract:
A time-marching Euler calculation for 2-D and quasi 3-D unsteady flows in oscillating blade rows is presented, based on a finite volume scheme with cell-vertex discretization in space and 2-step Runge-Kutta integration in time. Extra fluxes due to the deformation of the moving finite volumes are directly included in the conservation equations in the physical coordinate system. A zonal moving grid technique is used, in which only sub-regions near oscillating blades are moved to fit both the moving (blade) boundaries and fixed regions. For phase-shifted periodic conditions, the conventional ‘Direct Store’ method is used as a basis for comparison. Two alternative methods to save computer storage are proposed and preliminary demonstrations of their usefulness are given in the present calculations. Calculated results for unsteady flows in an oscillating flat plate cascade are in good agreement with those from two well-established linear methods, LINSUB and FINEL. The unsteady pressure distribution and aerodynamic damping calculated by the present method for a turbine blade test case (Aeroelasticity Workshop Standard Configuration No.4 cascade) agree well with the corresponding experimental data. Computations for an oscillating biconvex cascade in transonic flow conditions are performed, which show some strong nonlinear behavior of shock wave movement.
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Florio, Catherine S. "The Use of the Discrete Element Method to Study the Response of Packed Particles to a Pressure Wave." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-69041.
Abstract:
Abstract While a system of particles confined in a container forms a structure-like system, its response to mechanical loads has characteristics that are both similar to a comparable continuum and unique to the discrete nature of the particles. Even when packed together, local interactions are often discontinuous throughout the system and over time, resulting in complex local and bulk behaviors. The effects of the properties of the particles and their interactions may, therefore, result in local forces and stresses in response to a pressure wave that cannot be readily modeled by continuum based computational modeling methods. This work uses the discrete element method (DEM) to improve the understanding of the model and system parameters that influence the local interactions of individual particles, the forces that develop, and the energy that is stored or dissipated as a pressure wave passes through a confined system of particles. Loads with durations that varied over four orders of magnitude, from quasi-static to near-impulse, were applied to particle systems with and without a pre-compression load. The results of this study and methods described may help in the selection of appropriate modeling parameters for solution stability and accuracy and can guide the determination of physical properties to tailor the local and bulk behavior of a confined particle system.
Reports on the topic "Quasi-Physical Methods":
1
Karstensen, Johannes, Alexandra Andrae, Ludwig Bitzan, Jakob Deutloff, Christiane Lösel, Paul J. Witting, Nils O. Niebaum, et al. Student cruise: Observing techniques for Physical Oceanographers Cruise No. AL529. GEOMAR, 2020. http://dx.doi.org/10.3289/cr_al529.
Abstract:
Oct. 07 2019 – Oct. 10, 2019 Kiel (Germany) – Kiel (Germany) MNF-Pher-110The main purpose of the ALKOR cruise AL529 was the training of students in observational techniques applied by physical oceanographers. The students who participated in the trip attend the module "Measurement Methods of Oceanography" which is offered in the Bachelor program "Physics of the Earth System" at CAU Kiel. During the AL529 the students were instructed in instrument calibration and in the interpretation of measurement data at sea. In addition, the students had the opportunity to learn about working and living at sea and to explore and study the impact of physical processes in the western Baltic Sea, the sea at their doorstep. The observations show a quasi-synoptic picture of the hydrography and currents in the western Baltic Sea. Twice-repeated hydrographic and current sections across the Fehmarn Belt show well the short time scales where significant changes occur. A zonal section along the deepest topography, from about 10°40'E to 014°21'E, shows very nicely the two-layer system of outflowing low salinity and inflowing North Sea water. A bottom shield anchorage shows the currents in the water column and the near-bottom temperature and salinity variations in the Fehmarnbelt area.
2
Zanoni, Wladimir, and Ailin He. Citizenship and the Economic Assimilation of Canadian Immigrants. Inter-American Development Bank, March 2021. http://dx.doi.org/10.18235/0003117.
Abstract:
In this paper, we examine whether acquiring citizenship improves the economic assimilation of Canadian migrants. We took advantage of a natural experiment made possible through changes in the Canadian Citizenship Act of 2014, which extended the physical presence requirement for citizenship from three to four years. Using quasi-experimental methods, we found that delaying citizenship eligibility by one year adversely affected Canadian residents' wages. Access to better jobs explains a citizenship premium of 11 percent in higher wages among naturalized migrants. Our estimates are robust to model specifications, differing sampling windows to form the treatment and comparison groups, and whether the estimator is a non-parametric rather than a parametric one. We discuss how our findings are relevant to the optimal design of naturalization policies regarding efficiency and equity.
3
Schiller, Brandon, Tara Hutchinson, and Kelly Cobeen. Cripple Wall Small-Component Test Program: Dry Specimens (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, November 2020. http://dx.doi.org/10.55461/vsjs5869.
Abstract:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measures and documents seismic performance of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Three primary tasks support the earthquake loss-modeling effort. They are: (1) the development of ground motions and loading protocols that accurately represent the diversity of seismic hazard in California; (2) the execution of a suite of quasi-static cyclic experiments to measure and document the performance of cripple wall and sill anchorage deficiencies to develop and populate loss models; and (3) nonlinear response history analysis on cripple wall-supported buildings and their components. This report is a product of Working Group 4: Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. This present report focuses on non-stucco or “dry” exterior finishes. Paralleled by a large-component test program conducted at the University of California, Berkeley (UC Berkeley) [Cobeen et al. 2020], the present report involves two of multiple phases of small-component tests conducted at University of California San Diego (UC San Diego). Details representative of era-specific construction–specifically the most vulnerable pre-1960s construction–are of predominant focus in the present effort. Parameters examined are cripple wall height, finish style, gravity load, boundary conditions, anchorage, and deterioration. This report addresses all eight specimens in the second phase of testing and three of the six specimens in the fourth phase of testing. Although conducted in different testing phases, their results are combined here to co-locate observations regarding the behavior of all dry finished specimens. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load onto eleven cripple walls. Each specimen was 12 ft in length and 2-ft or 6-ft in height. All specimens in this report were constructed with the same boundary conditions on the top, bottom, and corners of the walls. Parameters addressed in this report include: dry exterior finish type (shiplap horizontal lumber siding, shiplap horizontal lumber siding over diagonal lumber sheathing, and T1-11 wood structural panels), cripple wall height, vertical load, and the retrofitted condition. Details of the test specimens, testing protocol (including instrumentation), and measured as well as physical observations are summarized. Results from these experiments are intended to support advancement of numerical modeling tools, which ultimately will inform seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100 Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings.
4
Wang, Wei, Michael Brown, Matteo Ciantia, and Yaseen Sharif. DEM simulation of cyclic tests on an offshore screw pile for floating wind. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001231.
Abstract:
Screw piles need to be upscaled for offshore use e.g. being an alternative foundation and anchor form for offshore floating wind turbines, although the high demand of vertical installation forces could prevent its application if conventional pitch-matched installation is used. Recent studies, using numerical and centrifuge physical tests, indicated that the vertical installation force can be reduced by adopting over-flighting which also improved axial uplift capacity of the screw pile. The current study extends the scope to axial cyclic performance with respect to the installation approach. Using quasi-static discrete element method (DEM) simulation it was found that the over-flighted screw pile showed a lower displacement accumulation rate, compared to a pitch-matched installed pile, in terms of load-controlled cyclic tests. Sensitivity analysis of the setup of the cyclic loading servo shows the maximum velocity during the tests should be limited to avoid significant exaggeration of the pile displacement accumulation but this may lead to very high run durations.
5
Schiller, Brandon, Tara Hutchinson, and Kelly Cobeen. Cripple Wall Small-Component Test Program: Wet Specimens I (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, November 2020. http://dx.doi.org/10.55461/dqhf2112.
Abstract:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4: Testing and focuses on the first phase of an experimental investigation to study the seismic performance of retrofitted and existing cripple walls with sill anchorage. Paralleled by a large-component test program conducted at the University of California [Cobeen et al. 2020], the present study involves the first of multiple phases of small-component tests conducted at the UC San Diego. Details representative of era-specific construction, specifically the most vulnerable pre-1960s construction, are of predominant focus in the present effort. Parameters examined are cripple wall height, finish materials, gravity load, boundary conditions, anchorage, and deterioration. This report addresses the first phase of testing, which consisted of six specimens. Phase 1 including quasi-static reversed cyclic lateral load testing of six 12-ft-long, 2-ft high cripple walls. All specimens in this phase were finished on their exterior with stucco over horizontal sheathing (referred to as a “wet” finish), a finish noted to be common of dwellings built in California before 1945. Parameters addressed in this first phase include: boundary conditions on the top, bottom, and corners of the walls, attachment of the sill to the foundation, and the retrofitted condition. Details of the test specimens, testing protocol, instrumentation; and measured as well as physical observations are summarized in this report. In addition, this report discusses the rationale and scope of subsequent small-component test phases. Companion reports present these test phases considering, amongst other variables, the impacts of dry finishes and cripple wall height (Phases 2–4). Results from these experiments are intended to provide an experimental basis to support numerical modeling used to develop loss models, which are intended to quantify the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100, Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings.
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Schiller, Brandon, Tara Hutchinson, and Kelly Cobeen. Cripple Wall Small-Component Test Program: Wet Specimens II (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, November 2020. http://dx.doi.org/10.55461/ldbn4070.
Abstract:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4 (WG4): Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. This report focuses stucco or “wet” exterior finishes. Paralleled by a large-component test program conducted at the University of California, Berkeley (UC Berkeley) [Cobeen et al. 2020], the present study involves two of multiple phases of small-component tests conducted at the University of California San Diego (UC San Diego). Details representative of era-specific construction, specifically the most vulnerable pre-1960s construction, are of predominant focus in the present effort. Parameters examined are cripple wall height, finish style, gravity load, boundary conditions, anchorage, and deterioration. This report addresses the third phase of testing, which consisted of eight specimens, as well as half of the fourth phase of testing, which consisted of six specimens where three will be discussed. Although conducted in different phases, their results are combined here to co-locate observations regarding the behavior of the second phase the wet (stucco) finished specimens. The results of first phase of wet specimen tests were presented in Schiller et al. [2020(a)]. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load onto ten cripple walls of 12 ft long and 2 or 6 ft high. One cripple wall was tested with a monotonic loading protocol. All specimens in this report were constructed with the same boundary conditions on the top and corners of the walls as well as being tested with the same vertical load. Parameters addressed in this report include: wet exterior finishes (stucco over framing, stucco over horizontal lumber sheathing, and stucco over diagonal lumber sheathing), cripple wall height, loading protocol, anchorage condition, boundary condition at the bottom of the walls, and the retrofitted condition. Details of the test specimens, testing protocol, including instrumentation; and measured as well as physical observations are summarized in this report. Companion reports present phases of the tests considering, amongst other variables, impacts of various boundary conditions, stucco (wet) and non-stucco (dry) finishes, vertical load, cripple wall height, and anchorage condition. Results from these experiments are intended to support advancement of numerical modeling tools, which ultimately will inform seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100,Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings.
7
Schiller, Brandon, Tara Hutchinson, and Kelly Cobeen. Comparison of the Response of Small- and Large-Component Cripple Wall Specimens Tested under Simulated Seismic Loading (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, November 2020. http://dx.doi.org/10.55461/iyca1674.
Abstract:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4: Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. Two testing programs were conducted; the University of California, Berkeley (UC Berkeley) focused on large-component tests; and the University of California San Diego (UC San Diego) focused on small-component tests. The primary objectives of the tests were to develop descriptions of the load-deflection behavior of components and connections for use by Working Group 5 in developing numerical models and collect descriptions of damage at varying levels of drift for use by Working Group 6 in developing fragility functions. This report considers two large-component cripple wall tests performed at UC Berkeley and several small-component tests performed at UC San Diego that resembled the testing details of the large-component tests. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load on cripple wall assemblies. The details of the tests are representative of era-specific construction, specifically the most vulnerable pre-1945 construction. All cripple walls tested were 2 ft high and finished with stucco over horizontal lumber sheathing. Specimens were tested in both the retrofitted and unretrofitted condition. The large-component tests were constructed as three-dimensional components (with a 20-ft 4-ft floor plan) and included the cripple wall and a single-story superstructure above. The small-component tests were constructed as 12-ft-long two-dimensional components and included only the cripple wall. The pairing of small- and large-component tests was considered to make a direct comparison to determine the following: (1) how closely small-component specimen response could emulate the response of the large-component specimens; and (2) what boundary conditions in the small-component specimens led to the best match the response of the large-component specimens. The answers to these questions are intended to help identify best practices for the future design of cripple walls in residential housing, with particular interest in: (1) supporting the realistic design of small-component specimens that may capture the response large-component specimen response; and (2) to qualitatively determine where the small-component tests fall in the range of lower- to upper-bound estimation of strength and deformation capacity for the purposes of numerical modelling. Through these comparisons, the experiments will ultimately advance numerical modeling tools, which will in turn help generate seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings. To this end, details of the test specimens, measured as well as physical observations, and comparisons between the two test programs are summarized in this report.