Showing papers in "Journal of The Chinese Institute of Engineers in 1986"
TL;DR: In this paper, the effect of fineness, mixing method and content of slag on the strength development of blended-slag mortar was investigated to explain the strength of blended slag mortar.
Abstract: Blast‐furnace slags cooled at different rates were used to study the effect of fineness, mixing method and content of slag on the strength development of blended‐slag mortar. Activator and curing temperature were used to activate the early strength. The microstructure of blended‐slag paste was also investigated in this study to explain the strengthen effect.
45 citations
TL;DR: A new key‐lock‐pair mechanism of access control in information system is proposed that is inspired by Wu and Hwang's result and has the following advantages:.
Abstract: A new key‐lock‐pair mechanism of access control in information system is proposed. Our method is inspired by Wu and Hwang's result. The most important and common advantages of our method are as follows: 1. The memory storage required for keys and locks is small. 2. The determination of an access right value is fast. 3. The construction of keys and locks is simple.
11 citations
TL;DR: A real‐time, speaker‐independent pitch extraction and four‐tone recognition system for isolated Mandarin speech: the pitch periods are extracted from the zero‐crossing interval sequence of speech; and the recognition algorithm is derived from the analysis of pitch contours of the four tones.
Abstract: Mandarin is a type of tone language, i. e., the tones are part of the phonemic make‐up of words (1). Basically, there are four tones in Mandarin. On the basis of the fact that the four individual tones in Mandarin have almost fixed patterns on their pitch variations, we have designed a real‐time, speaker‐independent pitch extraction and four‐tone recognition system for isolated Mandarin speech: The pitch periods are extracted from the zero‐crossing interval sequence of speech; and the recognition algorithm is derived from the analysis of pitch contours of the four tones. The system has been implemented on a microcomputer development system MDS‐286. The average four‐tone recognition rate for the digits “0” to “9”, uttered 10 times by 5 males and 5 females, is 90.2%. The response time is about 1.64s for one digit. Both the recognition rate and the response time can be further improved.
9 citations
TL;DR: In this article, the growth kinetics and cultivation technique of Spirulina platensis were studied by using 1 liter Roux-flask, and the optimum temperature and pH for Spirula platensis under continuous illumination of white fluorescent light were found to be 30°C and 9.2 klux respectively.
Abstract: Growth kinetics and cultivation technique of Spirulina platensis were studied by using 1 liter Roux‐flask. Optimum temperature and pH for Spirulina platensis under continuous illumination of white fluorescent light were found to be 30°C and 9.5 respectively. In the logarithmic growth phase, growth followed Monod's equation; the maximum specific growth rate, μm , and saturation constant, KL , were 2.0 day‐1 and 9.2 klux respectively. During the linear growth phase, it followed the equation: dX/dt=μmln (1+I 0 /KL )/ah 1, where I 0 is the growth limiting factor. Growth yield of the algae ranged 0.01–0.02 g‐cell/kcal. Photosynthesis efficiency ranged 6–12%. Growth was inhibited as Po 2 in the gaseous phase increased to 95%. An automatic controller for pH of culture medium was devised with the feeding of CO2 gas. Such an automatic operation promoted the algae productivity (4.5 g dry wt./l) and also improved the medium utilization.
9 citations
TL;DR: In this article, numerical solutions of the equations governing time-dependent, viscous, incompressible fluid flow past a circular cylinder are presented for Reynolds numbers 100, 200, and 500, based on the use of bodyfitted coordinate systems having a coordinate line coinciding with the body contour regardless of its shape.
Abstract: In this study, numerical solutions of the equations governing time‐dependent, viscous, incompressible fluid flow past a circular cylinder are presented for Reynolds numbers 100, 200, and 500. These solutions are based on the use of body‐fitted coordinate systems having a coordinate line coinciding with the body contour regardless of its shape. The implicit solution utilizes vorticity‐stream function formulation. All field equations are approximated using central differences and are solved simultaneously at each time step by SOR iteration. Numerical computations are carried out for flows of Reynolds number 100, 200, and 500, and the results of these numerical flow simulations illustrate the phenomenon that the vortices of the flow pattern shed alternately from the two sides of the cylinder and evolve toward a periodic configuration. These solutions also reveal the oscillatory character of the drag, the lift, and the torque that are experienced by the cylinder.
7 citations
TL;DR: In this article, the mean velocity and turbulence intensity in various cross-stream planes in a 90° square duct of 1.7 × 104 were measured using laser-Doppler velocimetry.
Abstract: Measurements of mean velocity and turbulence intensity in various cross‐stream planes in a 90° square duct of 1.5 radius ratio for the Reynolds number of 4.7 × 104 are presented. The bend was preceded by a short upstream tangent with air as flowing fluid. The technique used was laser‐Doppler velocimetry. The boundary layer at the bend inlet was found to be less than 0.1 of the hydraulic diameter and resulted in a secondary velocity maximum of 0.35 of the bulk flow velocity. The secondary motion was characterized by four‐vortex and six‐vortex structures near the bend exit. The results also showed that the turbulence intensity was anisotropic in the bend and in the short downstream distance from the bend exit. High levels of turbulence intensity were found near the duct walls and in the regions where Dean vortices appear.
7 citations
TL;DR: In this paper, the authors used the technique of correlation and spectral analysis to develope some basic result for earthquake engineering and building system identification, where the relative time delays as seismic waves propagate from basement to the roof are estimated as the optimum alignment of records.
Abstract: This paper studies the earthquake data which include the building seismic response data as well as the SMART‐1 array data, and use the technique of correlation and spectral analysis to develope some basic result for earthquake engineering and building system identification. In frequency domain analysis, the relative time delays as seismic waves propagate from basement to the roof are estimated as the optimum alignment of records. The ordinary and partial coherent spectrum are also employed to study the correlation of building input/output data. In time domain analysis, the input/output correlation study as well as the input signal management provide data of optimum input for system identification. The SMART‐1 array data was also used to study the spatial‐time correlation of seismic waves. This study can provide information for both building system identification and spatial variation of seismic waves.
6 citations
TL;DR: In this article, the authors apply modified and parallel models to the study of the engineering properties of lateritic gravels, using the reduction in the maximum grain sizes, to estimate the elastic moduli.
Abstract: This study aims to apply modified and parallel models to the study of the engineering properties of lateritic gravels These two models; using the reduction in the maximum grain sizes, are based on the investigation of the in situ grain size distribution of lateritic gravels The elastic moduli are also estimated by the differential scheme of composite materials in different proportions of laterite to gravels The experimental results show that the modified model has a better prediction on both one‐dimensional compressibility and shear strength properties, whereas the parallel one is an effective model for the permeability characteristics The elastic moduli predicted by the differential scheme are in good agreement with the experimental observations
4 citations
TL;DR: In this paper, a mixed method using modified stability array and mean square error (MSE) criterion is proposed for deriving reduced-order 2-transfer functions for discrete-time systems.
Abstract: A new mixed method using modified stability array and mean‐square error (MSE) criterion is proposed for deriving reduced‐order 2‐transfer functions for discrete‐time systems. More precisely, the modified Routh stability array is used to obtain the reduced‐order denominator, thus ensuring stability preservation, while the numerator is obtained by minimizing the mean‐square error between the unit step responses of the original system and reduced model. The main feature of the method is that it does not actually evaluate the system and model responses in the step of minimizing mean‐square error.
4 citations
TL;DR: In this article, a nonlinear fractional program based on a Cobb-Douglas production function is proposed for measuring the productive efficiency of the computer industry in Taiwan. But the model is not suitable for the case of non-constant returns to scale.
Abstract: To improve productive efficiency has long been considered as the main objective by most firms. In this paper, a model for measuring productive efficiency is proposed. So every firm can use its measured efficiency as a base for improvement. The model is a nonlinear fractional program based on a Cobb‐Douglas production function to accommodate non‐constant returns to scale. The model is also applied to measuring the productive efficiency of the computer industry in Taiwan.
3 citations
TL;DR: In this article, a trial and error method was devised to predict theoretically the moment load curves of reinforced concrete frames throughout the loading history, using the trilinear moment curve for critical sections suggested by Macchi [8], as well as the principle of virtual work to express the complexity of the frame behavior.
Abstract: The nonlinear behavior of reinforced concrete frames with sidesway is governed by two effects: first, the nonlinearity of materials due to cracking and the plastic behavior of materials, and second, the nonlinearity of geometry caused by the second‐order deformation. These two effects may interact, and the whole phenomenon is known as the nonlinearity of geometry and materials. Reinforced concrete frames are frequently used to resist wind or earthquake forces. These forces will accentuate the complexity of the frame behavior because of the continuous change of the shape of the bending moment diagram. The change of moment diagram will in turn affect the magnitude of the cumulative plastic rotations. A trial and error method was devised to predict theoretically the moment‐load curves of reinforced concrete frames throughout the loading history. This method utilized the trilinear moment‐curvature curve for critical sections suggested by Macchi [8], as well as the principle of virtual work to express...
TL;DR: The fundamental solutions for boundary element analysis of torsionai problems of a cylindrical anisotropic medium are presented in this article, where a suitable change of variables is suggested to reduce the governing equation to a simple form which is amenable to Hankel transforms.
Abstract: The fundamental solutions for boundary element analysis of torsionai problems of a cylindrical anisotropic medium are presented. The particular form of cylindrical anisotropy considered in this paper is the most general kind possible for axisymmetric torsion deformation. A suitable change of variables is suggested to reduce the governing equation to a simple form which is amenable to Hankel transforms. The explicit form of the fundamental solution for infinite space subjected to an axisymmetric ring of uniformly applied tangential forces is then derived. An existing solution for an isotropic medium is recovered. In addition, simple half‐space fundamental solutions for the torsion of a transversely isotropic medium are determined. The kernel functions obtained herein are readily implemented in the boundary element formulation of the axisymmetric torsionai problems.
TL;DR: The fundamental solutions required in boundary element analysis of torsionai problems of nonhomogeneous transversely isotropic media are derived in this paper, where the elastic constants are assumed to be variables as functions of cylindrical coordinates in the forms rα exp (λz) and rα (z+c) β.
Abstract: The fundamental solutions required in boundary element analysis‐of torsionai problems of nonhomogeneous transversely isotropic media are derived in this paper. The elastic constants of the nonhomogeneous medium are assumed to be variables as functions of cylindrical coordinates in the forms rα exp (λz) and rα (z+c) β . The displacement resulting from an axisymmetric ring of tangential forces applied in the interior of a infinite space and of a half‐space are obtained. The effects of nonhomogeneity are compared and discussed.
TL;DR: In this paper, the linear convective instabilities of a fluid layer of binary alloy, cooled from above and consequently frozen at the bottom, are considered and the effect of thermal buoyancy is insignificant and the freezing interface advances upward at a slow speed.
Abstract: The linear convective instabilities of a fluid layer of binary alloy, cooled from above and consequently frozen at the bottom, are considered. Due to the density jump across the freezing interface, some light material is then released and diffused by pressure and composition gradients. As a result of a low cooling rate, the effect of thermal buoyancy is insignificant and the freezing interface advances upward at a slow speed by accumulating the solidified binary alloy. As Schmidt number PL approaches infinity, instabilities set in stationarily at the marginal state. Cellular convective modes are possible, provided a destabilizing compositional profile occurs in the fluid layer, while morphological modes, associated with non‐cellular convection, require a constitutional supercooling near the freezing interface. In the absence of a constitutional supercooling, morphological modes are not important and cellular convective modes become dominant.
TL;DR: In this article, the finite element solutions of Navier-Stokes and energy equations for steady laminar flow and heat transfer around square prisms, with attack angles of 0° and 45° have been obtained for a gas of Pr=0.7.
Abstract: The finite element solutions of Navier‐Stokes and energy equations for steady laminar flow and heat transfer around square prisms, with attack angles of 0° and 45° have been obtained for a gas of Pr=0.7. The variations of surface shear stress, local pressure and Nusselt number are obtained over the entire prism surface including the zone beyond the point of separation. The predicted values of drag coefficients, the location of. separation, the average Nusselt number and the plots of velocity flow fields and isotherms are also presented. The trend of the present numerical results seems reasonable.
TL;DR: In this paper, the numerical solutions of the frequencies for various modes of waves propagated along the longitudinal axis of elliptical channels with various depths are solved, and the surface wave patterns and free surface displacement are given for the first four longitudinal modes of progressive surface waves.
Abstract: Progressive surface waves in elliptical channels are studied. For the special case of a circular channel, both, analytical and numerical solutions of the frequencies of longitudinal modes of progressive surface waves are considered first. The numerical solutions of the frequencies for various modes of waves propagated along the longitudinal axis of elliptical channels with various depths are solved. The frequencies obtained for elliptical channels are compared with those for rectangular channels and triangular channels for various depths. Also surface wave patterns and the free surface displacement are given for the first four longitudinal modes of progressive surface waves.
TL;DR: In this paper, the authors derived a rate equation based on the theory of Langmuir chemisorption and dealt with the activation energy of wool dyeing under different dyeing temperatures and dyestuff concentrations.
Abstract: In dye liquor, the hydrophobic group of acid dyestuff molecules often interacts with one another to form aggregates. For the purpose of investigating the aggregative effect of acid dyestuff on the activation energy of wool dyeing, this study derives a rate equation based on the theory of Langmuir chemisorption and deals with the activation energy of wool dyeing under different dyeing temperatures and dyestuff concentrations. The Arrhenius plot from the rate of different dyeing temperatures clearly indicates two straight lines which intersect at 60°C. It is clear that the activation energy found at temperatures below 60°C is higher than that at temperatures above 60°C. It is suggested that when temperatures are below 60°C, the acid dyestuff molecules are in an aggregated state, so that the activation energy below 60°C is higher than that above 60°C. It is also suggested that the higher the concentration, the higher will be the activation energy.
TL;DR: In this paper, a comparison between the results of transient velocity field and those of steady velocity field is made, and it is found that the transient velocity fields has the effect of increasing the ignition length and ignition time.
Abstract: In this study, transient ignition on a hot plate is analyzed numerically. In addition to the transient energy and species equations, the transient momentum equation is also considered. A comparison is made between the results of transient velocity field and those of steady velocity field. It is found that the transient velocity field has the effect of increasing the ignition length and ignition time. The effects of wall temperature, Prandtl number and Schmidt number are also studied.
TL;DR: In this paper, a squared magnitude Pade approximation technique is presented for model simplification of stable discrete-time systems, where the simplification is started from the squared magnitude function M(ejTω ) =G(mTω)G(eJTω ), where mTω is the z-transfer function of a given high order discrete time system.
Abstract: A squared magnitude Pade approximation technique is presented for the model simplification of stable discrete‐time systems. The simplification is started from the squared magnitude function M(ejTω ) =G(ejTω )G(e–jTω ), where G(z) is the z‐transfer function of a given high order discrete‐time system. The method is fully computer‐oriented and leads to a satisfactory approximation while preserving stability and minimum‐phase characteristics.
TL;DR: In this article, a modified Hermite polynomials series solution of a functional differential equation of scaled systems is obtained, in which the dependent variable is expressed by an infinite series of the modified Hermites.
Abstract: The modified Hermite polynomials series solution of a functional differential equation of scaled systems is obtained. The Hermite polynomials are modified from the conventional ones by using an additional parameter. In order to simplify the computational algorithm, the stretch operational matrix of the modified Hermite polynomials is introduced to solve such a functional differential equation. The key method is that the dependent variable is expressed by an infinite series of the modified Hermite polynomials. The expansion coefficients of the series are solved by the proposed effective computational algorithm, in which only one matrix inversion is required. An illustrative example is given. Very satisfactory computational results are obtained.
TL;DR: In this article, an unconditionally stable implicit algorithm for the direct integration of a linear structural dynamic equation of motion is presented, based on two simultaneous difference equations and a weighting factor G for solving displacement at the next time step.
Abstract: This paper presents an unconditionally stable implicit algorithm for the direct integration of a linear structural dynamic equation of motion. The algorithm is based on two simultaneous difference equations and a weighting factor G for solving displacement at the next time step. Unconditional stability is proven for the weighting factor G in the range from –0.466 to 0.140 in all undamped and damped cases. The unconditionally stable range of G can be extended, from –1.0 to 0.333, for certain types of structure. The amplitude decay and period variation are used as the basic parameters to compare the accuracy of the present algorithm with various other integration methods. A spring‐mass‐dashpot model is applied to illustrate the algorithm for transient and quasi‐static analyses.
TL;DR: In this article, three different ways of using fly ash, namely, partial replacement of cement, or sand, or both cement and sand in the cement mortar, were studied in this investigation.
Abstract: Three different ways of using fly ash, namely, partial replacement of cement, or sand, or both cement and sand in the cement mortar, were studied in this investigation. The replacement varied from 10 percent to 60 percent by weight. The effects of design parameters such as water‐cement ratio and curing temperature on the replacements were studied. In this paper, strategies of using fly ash in concrete construction were also proposed in order to conserve resources.
TL;DR: In this paper, a numerical analysis of magnetic field distribution in an air gap with the effects of slot depth and width is presented, where a dimensionless parametric approach is utilized to cover wide ranges of parameters that frequently appear in electric machine design.
Abstract: This paper presents a numerical analysis of magnetic field distribution in an air gap with the effects of slot depth and width. A dimensionless parametric approach is utilized to cover wide ranges of parameters that frequently appear in electric machine design. A nonlinear two‐dimensional Maxwell equation is solved by using a finite‐difference successive relaxation technique. Constant fluxes are applied for the investigation of nonlinear effect through the region of study, and average reluctances in the air gap are calculated and compared with the Carter number reported in existing literature. Flux plot with normalized air gap G=0.1; besides, various slot depth D, half slot width W, the Carter number with parameters G=0.1–0.2, D=0.2–3.0, and W=0–0.8 are presented.
TL;DR: In this paper, a two-phase testing technique is presented for analog circuit fault diagnosis systems, which isolates the faulty linear components in the first phase and then uses the computed linear component values obtained by phase 1 to determine the input-output characteristics of nonlinear components during phase 2.
Abstract: A two‐phase testing technique is presented for analog circuit fault diagnosis systems. The proposed technique isolates the faulty linear components in the first phase and then using the computed linear component values obtained by phase 1 to determine the input‐output characteristics of nonlinear components during phase 2. The faulty nonlinear components can thus be located. This two‐phase technique takes great advantage of low computational cost since the complex characteristics of the nonlinear components are not directly involved in the calculation.
TL;DR: In this article, a solution of the extended Graetz problem with prescribed wall heat flux and viscous dissipation in a semi-infinite axial region of a tube is obtained by functional analytic methods.
Abstract: A solution of the extended Graetz problem with prescribed wall heat flux and viscous dissipation in a semi‐infinite axial region of a tube is obtained by functional analytic methods. The energy equation is split into a set of partial differential equations to obtain a self‐adjoint formulism. Then, an algebraic characteristic equation of the eigenvalue problem for an arbitrary velocity profile is obtained by an approximation method in L 2[0, 1]. In addition, a backward recursive formula for calculating the expansion coefficients of the solution is developed.
TL;DR: In this article, the authors developed the asymptotic stability conditions of a closed-loop system with parameter variations and showed that the guaranteed cost can be made to be a Lyapunov function for the closedloop system.
Abstract: Stability study is essential in the control design of optimal quasi‐stationary tracking systems with parameter variations. In this paper, the asymptotic stability conditions of such systems given in the author's previous results [8, 13, 14] are developed. The conditions based on the design methods of traditional technique and model‐following technique can guarantee the closed‐loop system to be stable at the norminal conditions only. However, based on the guaranteed cost design technique, the closed‐loop system with allowable parameter variations is asymptotically stable because the guaranteed cost can be made to be a Lyapunov function for the closed‐loop system.
TL;DR: In this article, the Sturm-Liouville eigenvalue problem is solved as a linear algebraic form by using expansions of orthogonal functions and particular orthogonality.
Abstract: The Sturm‐Liouville eigenvalue problem can be dealt with as a linear algebraic form by using expansions of orthogonal functions and particular orthogonality. Due to the available recursive relation, these linear algebraic equations can be solved as a straightforward substitution. In order to speed up the convergence, an iterative improvement is used for finding eigenvalues.
TL;DR: In this paper, a more general equation was deduced on the orthogonal curvilinear coordinate system to unify the diversities among related theories and investigate the nearshore circulation on an arc-shaped coast.
Abstract: Nearshore circulation, produced by a wave‐induced radiation stress gradient, forms different circulation patterns under different wave characteristics and topographical conditions. A more general equation was deduced on the orthogonal curvilinear coordinate system to unify the diversities among related theories and to investigate the nearshore circulation on an arc‐shaped coast. The results show that circulation patterns depend on the flow torque factor which is in turn determined by both the wave characteristics and the topographical conditions. Due to the differences of this torque factor, the straight coast and the arc‐shaped coast will produce different circulation patterns.
TL;DR: In this article, the dilatancy rate of a sand in the triaxial drained test was proposed to evaluate the liquefaction potential of the sand, based on laboratory test data.
Abstract: In this paper, the dilatancy rate of a sand in the triaxial drained test was proposed to evaluate the liquefaction potential of the sand. Based on laboratory test data, the relationship between the dilatancy rate and the liquefaction resistance was developed. The effects of most of the factors affecting the liquefaction potential, such as relative density, confining pressure, overconsolidation, period of sustained loading, and fines content, are all considered in this relationship. It can be applied to various sands of hard and bulky particles. However, the effect of particle crushing should be taken into account for sands of flaky and friable particles.
TL;DR: In this paper, a self-adjoint formulism for the extended Graetz problem with prescribed wall flux and viscous dissipation between parallel plates is presented, and the expansion coefficients of the solutions on upstream and downstream regions can be explicitly obtained and unnecessary to match at the entrance.
Abstract: Functional analytic methods have been applied to the analysis of the extended Graetz problem with prescribed wall flux and viscous dissipation between parallel plates. First, the non‐self‐adjoint elliptic energy equation is decomposed into a set of first order partial differential equations to obtain a self‐adjoint formulism. Next, the induced eigenvalue problems are solved by applying an approximation method in a Hilbert space, and an algebraic characteristic equation is obtained. In addition, the expansion coefficients of the solutions on upstream and downstream regions can be explicitly obtained and unnecessary to match at the entrance.