ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677280

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This paper presents a method of eigen analysis to evaluate the accuracy of the time integration method in the structural dynamic analysis of both transient and steady state responses. Accuracy measure for transient response is evaluated by period elongation and amplitude decay after a complete cycle of response of an undamped system. The proposed method is a unique measure, independent of the initial conditions. Accuracy measure for steady state response is evaluated by the amplitude decay and phase angle of a frequency response. The accuracy measure proposed by this method can be applied to all ranges of ?t/T.The significance of the large range ?t/Tis discussed. The proposed method is used to evaluate the accuracy of three commonly used time integration methods: the Wilson method, the Newmark method and the Houbolt method.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677281

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A detailed numerical analysis is performed to investigate the effects of latent heat exchange, in connection with evaporation of the liquid film on the wall, on the natural convection heat transfer in vertical concentric annuli. Major governing parameters identified areGrT, GrM, Pr, Sc,andN.Results are specifically presented for an air‐water system under various heating conditions to illustrate the latent heat transport during the evaporation process. The effects of the channel length, ratio of radiiNand wetted wall temperature on the momentum, heat and mass transfer are examined in detail. Tremendous enhancement in heat transfer due to the exchange of latent heat was clearly demonstrated.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677282

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A developing system for supporting the construction of software prototypes should provide some automatic tools in order that the prototypes can be generated in shorter time and with lower cost. We present an integrated knowledge‐based rapid prototyping system (KBRPS). This system contains a graphic conceptual model for describing system behaviors; a frame‐based software requirements specification language (FSRSL) to represent the internal forms of the conceptual model and to further specify detailed activities and constraints; a database for storing specification files; and a knowledge base for storing rules of specification analysis and specification transformation. The specification analysis can check the consistency and completeness of requirements specifications. Specifications written in FSRSL can also be executed as a software prototype. If the prototype specifications meet the user's requirements, they can be automatically transformed into C language programs; otherwise the original specifications can be modified iteratively until a satisfactory prototype or system is obtained.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677283

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The fundamental theory of shear wave velocity was studied in this paper to select proper parameters for the regression model. Previous regression equations were examined, and the most rational regression model was pointed out. Regression equations were recommended for the clayey, silty, and sandy soils of the Taipei basin. The research showed (1) thatN‐value was not the best parameter if the effects of soil type and geologic effect were considered, (2) that the multiple regression model with parameters ofN‐value and depth implied a form of shear wave velocity with specific physical meaning, but these two parameters were not independent of each other, and (3) that the intrinsically linear model with the parameter of depth was acceptable when the local soils were first classified according to soil type and geologic effect – then itsR‐square value was comparable to theR‐square value of the multiple regression model.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677284

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In this paper, the problems of multiplicity and uniqueness of steady states in a nonadiabatic CSTR are discussed, using the Cholette's model. The result shows that the parametersm(the fraction of the total volume which is perfectly mixed) andn(the fraction of the feed entering the zone of perfect mixing) of Cholette's model seem to strongly determine the multiplicity and uniqueness region. When parametersmandnare changed, the exact region of multiplicity will be shifted. In addition, we derive the necessary and sufficient conditions for steady state multiplicity and uniqueness in the non‐ideal mixing of CSTR. As the non‐ideal mixing takes place in a real reactor, our results will be of significant use in chemical reactor design.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677285

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This study investigates theoretically and experimentally the mixing characteristics of a flow with initial momentum and density differences ejected from a multiple‐port diffuser into a uniform cross flow of a density stratified fluid. With the integral approach, the governing equations are established by taking the cross‐section integral over the jet and closed the problem with the specification of the entrainment function. The model predicts the trajectory and dilution of the jet as a function of horizontal position. In the laboratory experiment, a salt‐water filling process was used to create a linearly density‐stratified environment. The experimental results were obtained by towing a multiple‐port buoyant jet discharged at constant velocity through a stagnant, stratified fluid. Results show good agreement between the model prediction and the laboratory experiments.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677286

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Both batch and MSMPR (mixed‐suspension, mixed‐product removal) reactor systems were used in this study on particle size distributions and crystallization kinetics for zinc sulfide precipitation. The solution pH value was found to be the major factor influencing the particle size distribution and crystallization behavior of zinc sulfide. Temperature and presence of calcium also influence the crystallization kinetics, but the significant effects were found to be highly dependent on solution pH value. The MSMPR crystallization model gives a fairly good approximation of zinc sulfide precipitation.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677287

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

For the purpose of establishing seismic design criteria for engineering structures, it is desirable to assess the expected intensity of seismic strong ground motion at a site for various probability levels (i.e., Seismic Hazard Analysis). In order to consider the seismic hazard at a site, the predictive equations of ground motion are needed. A number of predictive relationships derived from regression analysis of strong‐motion data are available for horizontal peak acceleration, response spectral value, and Fourier amplitude value. Of the earthquake data recorded in the Taiwan area, the “rock site” data are chosen for the determination of ground motion parameters. By using the predictive equation of peak ground acceleration, the seismic hazard curve at a site can be calculated, and by using the model of spectral acceleration attenuation, the uniform hazard spectrum is developed. Finally, by using the proposed Fourier amplitude attenuation model and the mathematical theory of the maximum response of a single‐degree‐of‐freedom linear system, the non‐exceedance probability of the earthquake response spectrum at a site at a certain lifetime can also be developed. Comparisons between the effects of different ground motion parameters on the results of seismic hazard analysis are made.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677288

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

It is well‐known that a real system is always subject to the impact of unmodeled dynamics. In this paper, a cost function of weighting output error (i.e., the difference between the reference model output and the plant output) and control input is minimized by the theory of minimax optimization to reduce the effect of unmodeled dynamics. Furthermore, the stability and robustness of an adaptive controller are achieved by the utilization of a modified dead‐zone least‐squares parameter estimator with non‐vanishing gain matrices, and the constraint of plant parameter in a finite set of convex sets. The choice of the size of the dead zone and its effect on tracking error are also discussed.

ISSN:0253-3839    

DOI:10.1080/02533839.1990.9677289

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor