The application of the inverse definite minimum time (IDMT) overcurrent relay to power system protection is reviewed, and the present methods for determining its settings are briefly described. A computer program to c...
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The application of the inverse definite minimum time (IDMT) overcurrent relay to power system protection is reviewed, and the present methods for determining its settings are briefly described. A computer program to calculate relay settings based on a generalised procedure, and therefore suitable for both radial and interconnected ring systems, is then proposed. Its application to a specific interconnected system is explained. Two further programs have been developed to be used in conjunction with the first one. These assess, by a simulated circuit breaker tripping facility, how the IDMT protection would perform on an interconnected ring power system when there occurs either a failure of the main protection or a circuit breaker on the faulted section.
A finite-element procedure for the determination of buckling pressure of thin-walled cylindrical shells used in ocean structures is presented. The derivation of the elastic and geometric stiffness matrices is discusse...
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A finite-element procedure for the determination of buckling pressure of thin-walled cylindrical shells used in ocean structures is presented. The derivation of the elastic and geometric stiffness matrices is discussed in detail followed by a succinct description of the computer program developed by the authors during the course of this study for the determination of the buckling pressure. Particular attention is paid to the boundary conditions which strongly influence the buckling pressure. Applications involving the interstiffener buckling in submersible hulls and cylindrical shells with stepwise variation in wall thickness are considered and the results compared with the solutions and procedures available in the literature.
The application of the theory of voltage regulation on a distribution network to the problem of optimising the various voltage control facilities available is generally assumed to be well understood. However, with com...
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The application of the theory of voltage regulation on a distribution network to the problem of optimising the various voltage control facilities available is generally assumed to be well understood. However, with complex network arrangements, the wide variety and numbers of distribution transformers, and differing load patterns, a distribution engineer is faced with a major problem when attempting to optimise the voltage performance of a distribution network, while maintaining the voltages supplied to consumers within declared limits. The paper covers a theoretical approach to distribution network voltage performance, leading to the derivation of a parallelogram theory linking primary substation source busbar voltage and the tap setting on each distribution transformer on the network. Based on this parallelogram theory, a computer program has been developed which enables distribution networks to be surveyed in greater depth, thus enabling engineers to more readily identify problem areas. Overall the program provides a powerful and efficient means of assessing and optimising the voltages on existing networks, or modifying networks to accommodate additional loads, or for designing new networks. The program is adaptable for use on any MV/LV distribution network. The paper thus provides both a theoretical and practical approach to the problem of improving the voltage performance of distribution networks.
A package program was developed for the estimation of Michaelis-Menten parameters for enzymes that conform to different kinetic mechanisms. Data from different experimental schemes can be fitted with appropriate weigh...
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A package program was developed for the estimation of Michaelis-Menten parameters for enzymes that conform to different kinetic mechanisms. Data from different experimental schemes can be fitted with appropriate weighting factors to any of 6 mathematical models, corresponding to 5 kinetic mechanisms: ordered bi-bi, Theorell-Chance, rapid equilibrium random bi-bi, rapid equilibrium ordered bi-bi and ping pong bi-bi. The program also performs a significance test to discriminate between different candidate models. To illustrate the performance of the program, real data from kinetic experiments with glucose 6-phosphate dehydrogenase from Leuconostoc mesenteroides were fitted to different mathematical models, and the results are discussed. The program can be easily implemented for the fitting of kinetic data to any other model.
The paper presents a general computational method and the relevant computer program which can be easily used to perform availability/unavailability analysis on power-system configurations. The mathematical availabilit...
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The paper presents a general computational method and the relevant computer program which can be easily used to perform availability/unavailability analysis on power-system configurations. The mathematical availability formulation of the program is based primarily on: the tie sets (or cut sets) of the system configuration, the component failure rates and repair and maintenance times, some aspects of a Markov model of two states and the functional block concept. A real prerequisite for the successful utilisation of the program is the availability of realistic statistical data for the system components. For purposes of illustration, the computer program has been applied to evaluate the availability of two practical high-voltage/medium-voltage (HV/MV) substation configurations, from the standpoint of design, practical functionality and repair and maintenance procedures. The program is suitable in performing system availability/unavailability sensitivity analysis, based on value variations of system-component failure rates and repair and maintenance times.
A FORTRAN computer program, running on a Digital PDP 11-34 minicomputer, was developed for use in conjunction with a Cambridge Quantimet 720 image analyzer for the investigation of metaphase preparations in routine cy...
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A FORTRAN computer program, running on a Digital PDP 11-34 minicomputer, was developed for use in conjunction with a Cambridge Quantimet 720 image analyzer for the investigation of metaphase preparations in routine cytogenetics. During a short initiation phase the program is adapted to the type of metaphase being analyzed. The program is fast and its performance is good, even at low microscopic magnifications. It has other uses in biology for all investigations and characterizations of groups of small distinct elements widely spread within a preparation (e.g., autoradiography, bacteriology).
The approximate theory of ELF propagation in the Earth-ionosphere transmission line described by Booker (1980) is applied to a simplified worldwide model of the D and E regions, and of the Earth's magnetic field. ...
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The approximate theory of ELF propagation in the Earth-ionosphere transmission line described by Booker (1980) is applied to a simplified worldwide model of the D and E regions, and of the Earth's magnetic field. At 1000 Hz by day, reflection is primarily from the gradient on the underside of the D region. At 300 Hz by day, reflection is primarily from the D region at low latitudes, but it is from the E region at high latitudes. Below 100 Hz by day, reflection is primarily from the gradient on the underside of the E region at all latitudes. By night, reflection from the gradient on the topside of the E region is important. There is then a resonant frequency (∼ 300 Hz) at which the optical thickness of the E region for the whistler mode is half a wavelength. At the Schumann resonant frequency in the Earth-ionosphere cavity (∼ 8 Hz) the nocturnal E region is almost completely transparent for the whistler mode and is semi-transparent for the Alfvén mode. Reflection then takes place from the F region. ELF propagation in the Earth-ionosphere transmission line by night is quite dependent on the magnitude of the drop in ionization density between the E and F regions. Nocturnal propagation at ELF therefore depends significantly on an ionospheric feature whose magnitude and variability are not well understood. A comparison is made with results based on the computer program of the United States Naval Ocean Systems Center.
The photoperiod response characteristics of 2 cultivars each of seven long-day species of crop plants [wheat, barley, oats, rye, Polish rape, Argentine rape and flax] were determined by seeding at 33 biweekly interval...
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The photoperiod response characteristics of 2 cultivars each of seven long-day species of crop plants [wheat, barley, oats, rye, Polish rape, Argentine rape and flax] were determined by seeding at 33 biweekly intervals in a greenhouse at ***. 43'' N latitude. Parameters of segmented linear regression were estimated using a non-linear computer program. This gave good estimates of the length of the basic vegetative and reproductive phases, the photoperiod sensitivity and minimum optimal photoperiods. The photoperiod of importance apparently was that of the day of floral initiation. If the plant is old enough and the photoperiod of the day is not inhibitory, initiation will occur. At certain times of the year, the photoperiod changes so rapidly that flower initiation is prevented. Using this method of analysis, comparisons of large numbers of genotypes can be made.
Automatic computer programs (BASIC-PLUS) are developed to calculate Debye functions also for non integer exponents. Functions of this type occur in the heat capacity analysis of polymer crystals, if simple continuum a...
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Automatic computer programs (BASIC-PLUS) are developed to calculate Debye functions also for non integer exponents. Functions of this type occur in the heat capacity analysis of polymer crystals, if simple continuum approximations are used. The heat capacity of completely crystalline polyethylene is calculated and compared with experimental data.
A computer program for the assignment of13C resonances to the respective carbons of a known structure is presented. The algorithm is based on the prediction of chemical shift ranges from a data base containing carbon-...
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A computer program for the assignment of13C resonances to the respective carbons of a known structure is presented. The algorithm is based on the prediction of chemical shift ranges from a data base containing carbon-centered substructural environments and their corresponding chemical shifts. The method permits a stepwise solution of the assignment problem using chemical shift arguments up to a five-bond radius.
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