Showing papers in "Journal of The Chinese Institute of Engineers in 1989"

Residual strength of reinforced concrete columns exposed to fire

Abstract: Several methods were employed to evaluate the residual strength of reinforced concrete columns exposed to different durations of fire. These methods included the analytical method, ultrasonic tests, hammer tests and load tests. Fifty columns were involved in the tests. Calculated temperatures and residual strengths of the test columns were compared with those measured. Comparisons were also made between results from load tests and those from nondestructive tests. The results showed that using analytical procedures is acceptable while the nondestructive test methods are accurate only for shorter durations of fire.

The internal mass transport limited adsorption of cadmium on amorphous aluminum oxide

Abstract: The oxide/water interface of metal oxides has been identified as the most important inorganic mineral phase in water body and soil in controlling trace metal ion concentrations due to their relatively high surface area, abundance, and coating of clay minerals. In this paper, the effects of external and internal mass transport limitations on cadmium adsorption onto porous amorphous aluminum oxide/solution interfaces were studied. A modified two‐stage rate model was developed and used to interpret the time dependent experimental results. The effects of pH, aluminum oxide concentration, metal concentration and background electrolyte were performed and discussed.

Engineering correlations for soil deposits in taipei

Abstract: This study aims at establishing empirical correlations for the soil deposits in Taipei City. These correlations are valuable in the planning and preliminary design stages. For cohesive soils, correlations between (1) virgin compression index and nautral water content, (2) virgin compression index and initial void ratio, (3) coefficient of consolidation and liquid limit, and (4) angle of shearing resistance and plasticity index are proposed. Profiles of overcons‐olidation ratio (OCR) as well as strength ratio are presented. Relationships between the coefficient of earth pressure at rest and the angle of shearing resistance and the plasticity index have also been carefully studied. For cohesionless soils, correlations between (1) permeability and effective particle size, and (2) angle of shearing resistance and standard penetration test (SPT) TV‐value are presented. Due to inherent variations in the Taipei soil deposits, there are practical limitations and the correlations presented in the paper sh...

Reduced‐order modeling of MIMO discrete systems using bilinear block Routh approximants

Abstract: In this paper, a model reduction method based on expanding the matrix fraction description (MFD) of a multi‐input multi‐output (MIMO) discrete system into bilinear block Routh canonical continued fractions is presented. Both the frequency‐domain and time‐domain reduced‐order modeling procedures of the method are given. An example is included to demonstrate the method.

Fault restoration by optimizing switch configuration in distribution systems

Abstract: This paper describes a method of finding the optimal restoration configuration of inter‐feeder switches in a faulted distribution system. A feeder in a distribution system usually has several interfeeder switches properly located along the feeder to link it with other feeders. Under emergency situations, these switches are operated independently to minimize the loss of load and to prevent the distribution feeders from being overloaded or unbalanced. A computer program is developed to restore the faulted system by applying the binary integer programming (BIP) technique to find the optimal switching decisions by minimizing the objective function, which is defined according to the relief of feeder overloading and unbalance. A distribution system comprised of several substations in the Taiwan Power Company (Taipower) was selected for the simulation of optimal switching and to verify the accuracy and efficiency of this algorithm.

Polling of two queues with synchronized correlated inputs and zero walktime

Abstract: This paper studies the polling of two infinite queues by a synchronous server. The inputs to these queues are correlated and restricted to occur only at equally spaced time intervals. For simplicity, the walktime for the server to move from one queue to the other is assumed to be zero in this study. In essence, the problem studied in this paper is equivalent to a fixed service time queueing system which accepts two types of synchronized correlated inputs and adopts an alternating priority discipline. This paper contains a complete analysis of both the busy period and the waiting time. The validity of the analysis has been verified by computer simulations.

Kinetic study of reaction between zirconium and iodine

Abstract: Stress corrosion cracking (SCC) of zircaloy cladding is generally believed to be the major failure mode of current nuclear fuel in light water reactors. Iodine, an abundant fission product, has been identified to possibly cause zircaloy to become susceptible to SCC. An understanding of the kinetics of the reaction between zirconium and iodine is an essential part of the complex iodine induced SCC mechanism. The kinetics of reaction between zirconium and iodine are investigated by TGS‐2 thermogravimetry system at the temperature range of 300∼350°C. Results show that the activation energy, pre‐exponential factor and reaction order of molecular iodine are 43.8 kJ/mole, 3.1 mg/cm2‐min and 1.06, respectively. A study of the effect of surface texture on the kinetics is also performed by using the different cold rolled specimens whose textures are examined by an X‐ray diffraction method. Cold rolling will shift the basal pole to the rolling direction and only influence slightly the pre‐exponential facto...

Design electrically calibrated pyroelectric radiometer

Abstract: The electrically calibrated pyroelectric radiometer (ECPR) has been constructed. The system is composed of a nichrome‐film‐coated LiTaO3 pyroelectric detector, signal conditioning circuits, a heating circuit, a chopper system, and a microprocessor for power computation and synchronization as well as power display. It has been tested and compared with a commercial optical power meter with good consistence. Design considerations of the detector are discussed.

Adsorption of heavy metals from wastewater with waste activated sludge

Abstract: The purpose of this study is the investigation of the adsorption of heavy metals from wastewater with waste activated sludge (WAS) so as to increase the operational flexibility of activated sludge processes for the shock loading problems of heavy metals. By contacting the raw wastewater with WAS, before it entered the activated sludge process unit, some heavy metals in the wastewater were removed, and the pH value of the acidic wastewater rose. Five metals, Cu, Zn, Ni, Cd and Pb, were studied, some factors which affected this biosorption phenomena were investigated, and expressions of the adsorption isotherms were discussed. A semi‐empirical mass transfer‐adsorption model was developed to describe the kinetic experimental data.

The spectrum study of blood pressure during the disturbance of organic vascular beds

Abstract: Like electrical circuit components, the vascular beds in organs present impedance to waves in systemic circulation. In this study, the authors design an animal experiment to study the effect of the impedance to the pressure waves. We view the systemic circulation as an electrical circuit network, and interpret the vascular beds in organs as lumped components in the electrical circuit. Nature's designing of the systemic circulation minimizes the pressure wave reflection, and maximizes blood distribution. This is very similar to the concept adopted by electrical engineers in designing electrical circuits.

Preliminary experiments in acoustoelastic responses of a plastically deformed solid

Abstract: In this paper, the details of the experimental techniques and set‐ups needed in the acoustic birefringence measurement are given. To precisely determine the wave speeds, the Echo‐Overlap method with reflection mode is adopted. The details of the fabrication of a dual‐polarization ultrasonic shear‐wave transducer are also included. The anelastic effect which occurs in the acoustoelastic measurement of a plastically deformed steel (C1018) specimen is examined. The general assumption of slight orthotropy which is used in ultrasonic stress measurement of polycrystalline metal is tested. The annealing experiment shows that the preferred orientation of the cold‐rolled steel plate can not be changed by annealing the specimen at the recovery temperature. The measurement of the third order elastic constants of the steel specimen is also conducted.

Efficient task assignment for distributed computing system

Abstract: In this paper, a cost function considering execution time, communication time and even idle time, is employed to measure the performance of task assignment in a distributed computing system. We successfully develop a new mathematical model to describe this kind of cost function. The task assignment problem is formulated as one of directed‐to‐undirected graph mapping (DU‐mapping) which maps a directed acyclic task graph onto an undirected system graph. The search of optimal DU‐mapping is NP‐complete and is transformed into a state space search problem. Using an underestimation to A* algorithm, we can obtain an optimal DU‐mapping and prune the most nodes in a state space tree. An alternative overesti‐mation is applied to prune more nodes but also obtain a suboptimal DU‐mapping. Results of a wide range of experiments reveal that both estimates perform very well due to close evaluation of the real cost.

Kinetic study of stilbene synthesis with benzyltriphenylphosphonium bromide as phase transfer catalyst

Abstract: A kinetic study of the Wittig reaction for synthesizing stilbene is carried out by reacting benzaldehyde (C6H5CHO) with benzyltri‐phenylphosphonium bromide (BTPPB) in the NaOH(aq)/CH2Cl2(org) two‐phase reaction system. The rate of reaction depends on the agitation speed, the temperature and the concentrations of C6H5CHO, BTPPB, and NaOH. When the agitation speed is low, the reaction is highly affected by interface diffusion. The reactant rate constant, based on the SN 2 substitution mechanism and the activation energy are also determined. It is found that the activation energy obtained from the present study (Ea =11.97 kcal/mole) is less than that of the previously documented data (Ea =12.984 kcal/mole) in which benzyltriphenylphosphonium chloride (BTPPC) was used as a phase transfer catalyst.

Surface waves induced by uniform flow over a bulging bed

Abstract: This study mainly relates the gravity‐surface‐waves generated when a uniform flow passes through a bulging bed. This is done firstly by treating the linear surface waves generated when a uniform flow passing through single wave bed, then, secondly, by making use of the fundamental solution obtained as mentioned above, and coordinating it with the Fourier integral and contour integral, so that the gravity surface wave generated by the more generalized and simple wave bed can be treated. With respect to the analytical solution, the major premise of this assumption is still limited to the uniform and irrotational flow, and at the same time neglecting the influence of surface tension, in order to obtain the analytical result of the flow field. It is important to propose possible methods to analyze the surface wave generated by any form of bulging bed, so that the problem of gravity surface waves generated by the bulging bed can be reasonably solved by the analytical method.

Viscoelastic winding and unwinding mechanics

Abstract: In this paper a viscoelastic analysis of tape systems in winding/ unwinding process is presented. An analytical model is developed to predict stress and displacement fields in the tape system for any winding speed. A three‐parameter solid is used as an illustrated example. Results show that tape velocity is greater than 762 or less than 0.0762 cm/sec, the elastic solutions are applicaple. If the tape velocity is between 0.0762 and 762 cm/sec, the viscoelastic results are applicable.

A comparative study on the performance of several speech recognition techniques applied on the highly confusing mandarin syllables

Abstract: In this paper, the performance of several speech recognition techniques applied on the highly confusing Mandarin syllables were carefully compared, including dynamic time warping (DTW), the newly proposed DTW with superimposed weighting function (DTWW), the discrete hidden Markov models (DHMM) and the continuous hidden Markov models (CHMM) The vocabulary used here consists of 409 first tone isolated Mandarin syllables Due to the fact that many confusing sets exist in this vocabulary, the accurate recognition of these syllables is relatively difficult, and all the recognition experiments were performed in the speaker dependent mode After a series of 13 experiments, it was found that the recognition rate of the newly proposed DTWW (883) is higher than that of DTW (851), DHMM (650) and CHMM (839), and that the CPU time used for DTWW is 103 times that for DTW, 24 times that for DHMM and 43 times that for CHMM In addition, the memory space required for DTWW and DTW is 34 times that of DHMM

Interface‐state density and noise behavior of gamma‐irradiated MOSFET'S

Abstract: MOSFET's and MOS memory devices suffer the increase of interface state density and oxide trapped charge density after ionization radiation such as gamma rays. The drain‐current dependence and the gate‐voltage dependence of the flicker noise of the irradiated MOSFET's are illustrated in this paper. The annealing effect, the bias effect, and the total dose effect on the noise behavior are shown. It is also shown that the change of the interface state density is essential to the noise change and the change of oxide trapped charge density may cause the “apparent” change of MOSFET's flicker noise after gamma irradiation.

Performance study on a new reservation dual‐bus token passing protocol

Abstract: The major advantage of token‐passing‐bus local area networks (LANs) is its collision‐free characteristic but its drawback is the overhead in passing the token to idle users when the channel load is light. It is commonly known that the system performance can be increased considerably by increasing the capacity of the bus. One way of increasing the bus capacity, and also the system reliability, is to increase the number of buses. In this paper, we propose adding a second bus to provide high bandwidth as well as reliable service for token‐passing‐bus LANs. The second bus proposed here normally is used for reservations so that the token on the data bus is dynamically passed to ready users for packet transmission. Furthermore, it will take the place of the data bus when the data bus fails. The protocol discussed here is a reservation token‐passing protocol which not only is collision‐free but also minimizes the token‐passing delay. The analysis of this dynamic token‐passing protocol is provided with b...

A study of uv preionization pulsed tea CO2 laser

Abstract: A uniform volumetric discharge was obtained by means of an auxiliary UV preionization in a home‐made TEA CO2 laser. The maximum output pulse energy of this laser system was about 12J per pulse with a pulse duration of 80 ns. The ratio of electric field to neutral particle density (E/N) in this laser was 7.6×10‐16 V cm2. The peak power and pulse shape of the laser were studied. The time delay between the predischarge and the maindischarge during the stable operation of this laser system has also been studied. It was observed that the laser was operating with uniform glow discharges when the time delayed between the predischarge and the maindischarge was in the range of 1.0 μs to 6.0 μs. The spark array used as a preionizer for producing the UV radiation in this system is new, simple, durable, and can be easily fabricated.

System identification of bridges with nonlinear foundations

Abstract: In the present study, the nonparametric method of system identification proposed by Masri et al. has been used to treat simulated earthquake response data of a bridge with nonlinear foundations. It is found that the method is promising for estimation of functions which represent the dynamic characteristics of bridges and provides a sound basis for study of the safety assessment of a bridge by using earthquake response data of the bridge.

Turbulent boundary layer of water waves near a smooth bottom

Abstract: A one‐layer model describing wave‐induced turbulent flows near a smooth bottom is presented. A time‐invariant effective viscosity model, which is more realistic under natural conditions, is specified near a smooth bottom. The first and second order solutions are presented. These include the velocity profile, shear stress, friction Investigated. These include the velocity profile, shear stress, friction factor and mass transport. The present study simplifies much of the mathematical complexity in many of the existing models. Furthermore, the results compare favorably with available observations, indicating that the approach adopted in the present model is physically sound.

Parameter identification of a class of nonlinear systems with numerical optimization technique

Abstract: A time domain technique for the identification of unknown parameters in the nonlinear system of some given structures is presented. The nonlinearities considered in this paper are in the f...

Combustion and gasification of individual coal particle during pyrolysis

Abstract: This work studies the combustion and gasification behavior of individual coal particles in a hot environment The model contains (1) heat and mass transfer and pyrolysis within the particle, (2) thermal radiation, diffusion and combustion of the reactive gases outside of the particle The stages of preheating, ignition, and combustion are discussed separately An index of t 9550/t 50–5 is proposed and works very well for identifying the border of heat trnasfer controlled regime and the kinetically controlled regime for both the combustion and the gasification processes The conditions of higher temperature and larger particle favor the heat transfer controlled regime and vice versa In the kinetically controlled regime the reactivity is very sensitive to the particle size and the gas temperature, especially for the combustion process The border for combustion is confined to the ranges of smaller particle size and lower surrounding air temperature while compared with the gasification process Th

Multiple roots reverse Cuthill‐McKee method for reducing the bandwidth and profile of finite element systems

Abstract: We present an algorithm which uses a new relation vector called the “adjacent elements of each node” and “multiple roots” to replace the “adjacent nodes of each node” and “single root”, which are used in the reverse Cuthill‐McKee (RCM) method. The “adjacent elements of each node” can be formed easily from the “adjacent nodes of each element” which is a basic given array in a finite element system. The required computer storage is significantly less than the other methods using “adjacent nodes of each node”. The listing of FORTRAN subroutines for the proposed algorithm is given. These subroutines can be used directly in the existing finite element system. Since the required storage is small, these subroutines are extremely effective for microcomputers.

The preparation and characteristics studies of microencapsulated cholesteric liquid crystals (I)

Abstract: This paper deals with the enmicrocapsulation of cholesteric liquid crystals by the colloid coaversation process. This incident light reflection study reveals that the encapsulated liquid crystal films sustain highly sensitive and precise temperature gradients with responding abilities determined by their iridescent coloration.

Analysis for vertical velocity of seismic waves

Abstract: Presented here are the results of seismic wave velocities analyzed using the acceleration time‐histories recorded at the downhole strong motion array of the Lotung large scale seismic test site during the May 20, 1986 Hualien earthquake. The spectral ratios between the surface and downhole accelerograms were used to identify the frequencies of maximum amplification of soil layers, and an elastic 1‐D wave propagation model was proposed to estimate the wave velocities of the ground during the earthquake. The results obtained indicate that significant reduction of shear wave velocity as well as soil modulus was induced by earthquake excitation as compared to the values obtained from low strain level soil testings.

Life test of a sealed-off c02 laser with sn02 coated cathodes

Abstract: A sealed‐off CO2 laser with an intracavity structure and dual discharge sections has been built to test its lifetime under different treatments of cathodes. The output characteristics of this laser system, under different discharge conditions, have also been investigated. Several techniques, such as the sealing of optical components on a laser tube, the coating of tin‐oxide (SnO2) on stainless steel cathodes, and the making of a discharge tube of three layers, are established to construct this tube. By using SnO2 coated SUS 304 cathodes and a gas mixture of CO2:N2:He:Xe:H2= 15:14:65:4:2 in this laser tube, an operational lifetime in excess of 1,800 hours and an output power up to 52W/m are obtained.

Evaluation of turbo and hydro‐generator torques due to electromechanical interaction

Abstract: The computer prediction of turbogenerator behaviour following fault or disturbance conditions has become an important feature in the assessment of machine system design, pre‐commissioning test appraisals, system operational procedures, machine monitoring strategy and post‐event damage diagnoses. In this paper computer methods are described to assess the comparative severity of various electrical faults and disturbances, the effect of specific operational practices together with the prediction of peak torsional transient behaviour. This paper is supported by realistic examples simulating the transient behaviour of a number of generational units.

Deterministic and probabilistic contingency selection

Abstract: Steady‐state contingency selection is performed on the Taiwan power system using both deterministic and probabilistic approaches. In the deterministic approach, both the real power performance index (PIp) and the voltage performance index (PIv) are evaluated to reach the desired ranking lists of line outages. Generator reactive power output limits (Q‐limits) are taken into account throughout the contingency selection procedure. To examine the effect of voltage control on contingency selection, both the case with a fixed tap changer position and the one with a variable tap changer position are considered. An important observation from this study is that the masking problem, which has been reported to take place in real power contingency selection, does not seem to appear in voltage contingency selection. Thus, it is recommended that in voltage contingency selection the summation in PIv be made over all buses while in real power contingency selection the summation in PIp be carried out only on over...