摘要:

Two numerical calculation procedures are presented for computing the wave diffraction by a surface‐piercing structure in an ocean of finite depth: a finite element method which incorporates circular boundary dampers and a finite element method which incorporates infinite elements as the radiation boundary condition. The present results agree with those available from analytical solution and integral equation method. Computational savings in CPU suggest that the application of the finite element methods may be extended to more complicated systems of multiple structures.

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676798

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The governing equations for the non‐linear vibrations of machine‐isolator‐floor systems are derived from the principle of virtual work. The averaging technique and the method of multiple scales are used to solve the problem. The main purpose of the present paper is to deal with the second harmonic and the ½ subharmonic excitations. The Routh‐Hurwitz criterion is used to check the stability of the ½ subharmonic excitations. It is found that there exists a threshold value of the dynamic loading beyond which the system becomes unstable. The numerical results show that the threshold values become larger for a stiff isolator or/and for a large supporting area of the machine, but become smaller for a heavy machine.

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676799

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Dowex MSC‐1 is a porous polymeric resin with uniform pore size in the range of 200–400Å. It is a specially prepared copolymer of styrene and divinyl‐benzene. A functional group of the nature of ‐SO3H is incorporated in the polymer matrix. Its two pertinent properties, diffusivity and equilibrium sorption capacity, are of paramount concern to chemical processes. A batch reactor of about 1‐liter size, equipped with stirrer and baffle, was used for the experimental study of the sorption and diffusion in Dowex MSC‐1. A constant temperature water bath with temperature controller was used to maintain the isothermal condition of the runs. Alcohols of C3, C4and C5were used as the solutes and benzene was used as the solvent. The temperatures chosen for this study were 10 to 40°C, all at atmospheric pressure. The pore diffusion coefficients obtained were in the order of magnitude of 10‐6‐10‐7cm2/sec, activation energies of diffusion were approximately 4–7 kcal/g‐mole, and heats of adsorption were 1–3 kcal/g‐mole. It is of interest to note that the diffusion rate of the alcohols is in the following order:

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676800

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The elastic stresses due to homogeneous long elliptical cylinder inclusions have been solved by using the Eshelby method. The coefficientSijkeinside the inclusion is consistent with that of Brown and Clarke.

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676801

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676802

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The reduction of response deviation due to plant parameter changes is investigated. The algorithms are developed based on the frequency domain design technique of optimal theory. The obtained controllers are in transfer‐function matrix form. The approach for obtaining the low sensitivity controller gain is different from the methods presented in the literature since the types of controller gain were prespecified and the design were carried out in the time domain. From the example, it shows that the trajectory sensitivity has been reduced significantly.

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676803

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Since the trajectory sensitivity can not be modeled accurately in a closed‐loop formulation, the linear preregulator design techniques are investigated to approximate the sensitivity information, and two methods leading to transfer‐function matrix form are developed. The obtained control systems have shown much improvement in reducing the sensitivity, specially for Method B. The advantages of Method B over Method A are that the difficulty of obtaining the steady state control law in terms of the reference input can be prevented and that the controller containing an integral action can be obtained to ensure that there is no steady‐state error.

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676804

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676805

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Imbalance on early and late channels of full‐time PN (pseudorandom noise) code tracking loops always incurs a certain amount of error bias. Imbalance phenomena are due to the dissimilarity of channel corrrelators, filters in general and squaring circuits in noncoherent loops. In this paper, a quantitative analysis of the error‐bias and imbalance relationship is derived. It is worth noting that error bias is strongly dependent on signal to noise ratio (SNR), signal loss, and the difference between the filter responses. An illustrative example considering one‐pole filter imbalance is also described. The result shows that the noise‐induced error bias term is inversely proportional to SNR and to the difference between the cut‐off frequencies for certain code lengths.

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676806

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1985.9676807

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor