Towards Computer-Based Microstructure Models for Cement-Based Systems

1986 ◽  
Vol 85 ◽  
Author(s):  
Hamlin M. Jennings
Keyword(s):  
Computer Model ◽  
Specific Problem ◽  
Computer Models ◽  
Scientific Basis ◽  
Incremental Change ◽  
Important Development ◽  
Computer Based

ABSTRACTComputer-based models represent an important development that should provide a scientific basis for in-depth predictions of the behavior of materials. Aspects of microstructure models for cement-based systems are described. A computer model is described that can incorporate many assumptions in the form of sub-models. Specific algorithms are selected to solve specific parts of the problem. The algorithm chosen depends on specific problem requirements at each stage of calculation, and these problem requirements may not be anticipated in advance. An important part of these computer models is that they incorporate a file of numbers, representing the microstructure, which can be operated on to effect an incremental change in the system.

Interpreting Open- and Closed-Loop Transfer Relations Between Cardiorespiratory Parameters: Lessons Learned from a Computer Model of Beat-to-Beat Cardiovascular Regulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 237-240
Author(s):  
P. Hammer ◽  
D. Litvack ◽  
J. P. Saul
Keyword(s):  
Computer Model ◽  
Closed Loop ◽  
Computer Models ◽  
Cardiovascular Regulation ◽  
Cardiovascular Control ◽  
Lessons Learned ◽  
Multiple Systems ◽  
Response Characteristics ◽  
Similarities And Differences

Abstract:A computer model of cardiovascular control has been developed based on the response characteristics of cardiovascular control components derived from experiments in animals and humans. Results from the model were compared to those obtained experimentally in humans, and the similarities and differences were used to identify both the strengths and inadequacies of the concepts used to form the model. Findings were confirmatory of some concepts but contrary to some which are firmly held in the literature, indicating that understanding the complexity of cardiovascular control probably requires a combination of experiments and computer models which integrate multiple systems and allow for determination of sufficiency and necessity.

scholarly journals Computer models of spiral structure

1970 ◽  
Vol 38 ◽  
pp. 368-372 ◽  
Author(s):  
F. Hohl
Keyword(s):  
Motion Picture ◽  
Computer Model ◽  
Spiral Structure ◽  
Galactic Disk ◽  
Equations Of Motion ◽  
Computer Models ◽  
The Self ◽  
Large Numbers ◽  
Self Consistent

A computer model for isolated disks of stars is used to study the self-consistent motion of large numbers of point masses as they move in the plane of the galactic disk. The Langley Research Center's CDC 6600 computers are used to integrate the equations of motion for systems containing from 50000 to 200000 stars. The results are presented in the form of a motion picture.

Parameter Screening in Statistical Dynamic Computer Model Calibration Using Global Sensitivities

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Dorin Drignei ◽  
Zissimos P. Mourelatos
Keyword(s):  
Sensitivity Analysis ◽  
Computer Model ◽  
Model Calibration ◽  
Simulation Models ◽  
Computer Models ◽  
Automotive Application ◽  
Transient Signals ◽  
Sensitivity Indices ◽  
Calibration Algorithm ◽  
Computationally Intensive

Computer, or simulation, models are ubiquitous in science and engineering. Two research topics in building computer models, generally treated separately, are sensitivity analysis and computer model calibration. In sensitivity analysis, one quantifies the effect of each input factor on outputs, whereas in calibration, one finds the values of input factors that provide the best match to a set of test data. In this article, we show a connection between these two seemingly separate concepts for problems with transient signals. We use global sensitivity analysis for computer models with transient signals to screen out inactive input factors, thus making the calibration algorithm numerically more stable. We show that the computer model does not vary with respect to parameters having zero total sensitivity indices, indicating that such parameters are impossible to calibrate and must be screened out. Because the computer model can be computationally intensive, we construct a fast statistical surrogate of the computer model which is used for both sensitivity analysis and computer model calibration. We illustrate our approach with both a simple example and an automotive application involving a road load data acquisition (RLDA) computer model.

scholarly journals Methodological and computer-based support for choosing underground utility networks renovation method

2018 ◽  
Vol 230 ◽  
pp. 02010
Author(s):  
Dmitriy Goncharenko ◽  
Ihor Shumakov ◽  
Olha Starkova ◽  
Alevtyna Aleinikova ◽  
Revaz Mikautadze
Keyword(s):  
Service Life ◽  
Computer Models ◽  
Software Tools ◽  
Safe Operation ◽  
Multicriterion Optimization ◽  
Repair Method ◽  
The Status ◽  
Computer Based ◽  
Effective Organization

The article is devoted to the methodological and software tools for choosing organizational and technological solutions to maintain sewage collectors in an operable state to increase their service life. Such a tool must take into account a set of factors that affect the operation of sewer collectors and form a system, the implementation of which would improve the existing principles of monitoring the status of sewer collectors, identify effective organization and technological solutions of their renovation by taking into account factors that affect their safe operation, the facilities risk of accidents categories, conditions and parameters of works performance. For determining the optimal options for the renovation of the sewer collector using the developed mathematical and computer models, the results of problems solving were generalized: one-criterion optimization subject to the choice of one repair method; one-criterion optimization subject to the choice of different repair methods for the areas; multicriterion optimization.

Room Acoustic Modelling Techniques: A Comparison of a Scale Model and a Computer Model for a New Opera Theatre

2011 ◽  
Vol 18 (3-4) ◽  
pp. 259-280 ◽  
Author(s):  
Jens Holger Rindel
Keyword(s):  
Satisfactory Agreement ◽  
Computer Simulations ◽  
Computer Model ◽  
Computer Modelling ◽  
Computer Models ◽  
Scale Model ◽  
Acoustic Design ◽  
Acoustic Modelling ◽  
Scale Modelling ◽  
Modelling Techniques

Today most acoustic consultants are using room acoustic computer models as a basis for their acoustic design. However, room acoustic scale modelling is still being used for the design in some major projects, although the costs and the time needed are significantly larger than those related to computer modelling. Both techniques were used by the author in a project for a new opera theatre; first the acoustical design was based on computer simulations using the Odeon software, and next a 1:20 scale model was built and tested. In the paper the results obtained with the two different modelling techniques are compared, and in general a satisfactory agreement has been found. The advantages and drawbacks related to each of the modelling techniques are discussed.

An Interdisciplinary Guided Inquiry on Estuarine Transport Using a Computer Model in High School Classrooms

2012 ◽  
Vol 74 (1) ◽  
pp. 26-33 ◽  
Author(s):  
Kit Yu Karen Chan ◽  
Sylvia Yang ◽  
Max E. Maliska ◽  
Daniel Grünbaum
Keyword(s):  
Computer Model ◽  
Transport Model ◽  
Computer Models ◽  
Thinking Skills ◽  
Critical Thinking Skills ◽  
National Science Education Standards ◽  
Education Standards ◽  
Scientific Methods ◽  
Interdisciplinary Interaction ◽  
K 12

The National Science Education Standards have highlighted the importance of active learning and reflection for contemporary scientific methods in K–12 classrooms, including the use of models. Computer modeling and visualization are tools that researchers employ in their scientific inquiry process, and often computer models are used in collaborative projects across disciplines. The goal of this project was to develop and field-test a module that used a computer model to teach marine sciences content in an applied, inquiry-based, and collaborative manner. Students used an estuarine transport model to explore the question of how circulation patterns affect planktonic organisms, demonstrating the interdisciplinary interaction of physics and biology. Our experience suggests that computer models, when used for inquiry, can help foster students' understanding of the nature of science and critical-thinking skills.

scholarly journals Possibility of using Matlab application to propose fuzzy computer model

2021 ◽  
Vol 1199 (1) ◽  
pp. 012020
Author(s):  
S Hrehova ◽  
J Husár ◽  
V Hladký
Keyword(s):  
Computer Model ◽  
Industry 4.0 ◽  
Fuzzy Logic Controller ◽  
Historical Data ◽  
Computer Models ◽  
Fuzzy Approach ◽  
Software Applications ◽  
Proposed Model ◽  
The Creation ◽  
The Individual

Abstract More and more organizations in various fields apply the principles of the Industry 4.0 philosophy. The result, among other benefits, is the acquisition of a large amount of data. Data can be of great importance to them in terms of decision support, analysis and, last but not least, as a resource for simulations and computer models. Currently, various approaches and software applications can be used to create models. One of the applications that allows the creation of computer models in various fields is Matlab. Diversity of use is ensured by different sets of tools, which are specifically focused on individual areas and thus provide the necessary tools. In the presented paper we focus on the possibilities of using fuzzy approach in the design of a computer model in the field of heating with the tools of the Fuzzy Logic Controller toolbox. The basis for creating the model will be historical data obtained from the real object. The individual tools of the toolbox, the creation and presentation of rules will be described, as well as the connection of the proposed model with the Simulink environment.

Validation of Computer Models for Nuclear Material Shipping Packages

2007 ◽  
Author(s):  
Narendra K. Gupta ◽  
Eugene P. Shine ◽  
Richard C. Tuckfield ◽  
Jeffrey T. Fong
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Computer Model ◽  
Thermal Response ◽  
Mesh Size ◽  
Computer Code ◽  
Computer Models ◽  
Physical Reality ◽  
Nuclear Material ◽  
Convergence Criteria

Computer models are abstractions of physical reality and are routinely used for solving practical engineering problems. These models are prepared using large complex computer codes that are widely used in the industry. Patran/Thermal is such a finite element computer code that is used for solving complex heat transfer problems in the industry. Finite element models of complex problems involve making assumptions and simplifications that depend upon the complexity of the problem and upon the judgment of the analysts. The assumptions involve mesh size, solution methods, convergence criteria, material properties, boundary conditions, etc. that could vary from analyst to analyst. All of these assumptions are, in fact, candidates for a purposeful and intended effort to systematically vary each in connection with the others to determine there relative importance or expected overall effect on the modeled outcome. These kinds of models derive from the methods of statistical science and are based on the principles of experimental designs. These, as all computer models, must be validated to make sure that the output from such an abstraction represents reality [1,2]. A new nuclear material packaging design, called 9977, which is undergoing a certification design review, is used to assess the capability of the Patran/Thermal computer model to simulate 9977 thermal response. The computer model for the 9977 package is validated by comparing its output with the test data collected from an actual thermal test performed on a full size 9977 package. Inferences are drawn by performing statistical analyses on the residuals (test data – model predictions).

Reducing the Complexity When Modelling Damping in Vibrating Systems

2012 ◽  
Author(s):  
Hugh Goyder
Keyword(s):  
Computer Simulations ◽  
Computer Model ◽  
Relative Velocity ◽  
Frequency Response Function ◽  
Usual Method ◽  
Theoretical Interest ◽  
Frequency Spectra ◽  
Computer Based ◽  
Vibrating Systems ◽  
Electrical Theory

If a frequency spectra or frequency response function is known for a structure what physical model can be generated to represent it? This is an important question for computer based simulations where a translation must be made between a spectra and a computer model. This is particularly difficult if damping is to be modelled. Investigation of electrical theory shows that this problem has been examined in detail due to the need to construct circuits that have specific spectra. However, before ideas can be borrowed from electrical theory it is necessary to develop vibration theory so that it aligns perfectly with electrical theory. To achieve this a method for representing mass is suggested which is a generalisation of the usual method and involves using a system of levers so that force is equal to mass times the derivative of relative velocity rather than absolute velocity. It is then shown that following electrical theory a damped spectra may be represented by an undamped sequence of masses and springs terminated by just one dashpot. Such a model is of considerable theoretical interest as well as having utility in computer simulations.

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