Ball, JE 1987, 'A comparison of the hydraulics in three urban drainage models.'.
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Modelling of urban drainage systems is becoming an increasingly important aspect of the management and operation of drainage systems. An important feature of the modelling process is the techniques used in the modelling of both free surfaces and pressurized flow and the different results which alternative techniques will predict. The predicted hydrographs from three models, i.e. ILSAX, SWMM and PIPENET, are compared for situations where free surface and pressurized flow conditions exist in the network. Also discussed will be the theoretical basis for each of the routing techniques employed by these models.
Ball, JE 1987, 'Importance of dynamic wave components for pipe flows.'.
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Presented are the results of an investigation into the magnitude of the terms in the full dynamic wave equation of motion and the influence of neglecting terms upon the predicted hydrograph propagation. A pipe Froude number is proposed as a criteria for selection of the terms in the equation of motion to be included for accurate prediction of hydrograph propagation.
Durance, G, Hogg, GR, Tendys, J & Watterson, PA 1987, 'Studies of equilibrium in the AAEC rotamak', Plasma Physics and Controlled Fusion, vol. 29, no. 2, pp. 227-244.
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LOGANATHAN, P & SUTTON, PM 1987, 'PHOSPHORUS FRACTIONS AND AVAILABILITY IN SOILS FORMED ON DIFFERENT GEOLOGICAL DEPOSITS IN THE NIGER-DELTA AREA OF NIGERIA', SOIL SCIENCE, vol. 143, no. 1, pp. 16-25.
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We investigated in phosphorus (P) status of 12 well-drained to moderately well-drained soil profiles along an east-west transect in the Niger Delta area of Nigeria, by determining available P estimated by the methods of Bray and Kurz no. 1, Bray and Kurtz no. 2, Olsen and Truog, and the various P fractions. Total P in the six profiles of soils developed on Coastal Plain sands (CPS) ranged from 281 to 1469 ppm mean, 821), and total P in the four profiles of soils developed on Meander Belt deposits (MBD) and Sombreiro Warri deposits (SWD) ranged from 63 to 293 ppm (mean, 133). The two profiles in the transitional zone between CPS and SWD had total P of 326 to 595 ppm (mean, 441). Organic P ranged from 11 to 338 ppm and constituted 3 to 44% of total P. Inactive inorganic P accounted for 9 to 65% of total P. The relative abundance of the various active inorganic P forms was, in decreasing or der, Fe-P, Al-P, and Ca-P, except in three of the profiles of MBD-SWD region, where Ca-P was nearly equal to or slightly higher than Al-P. The results showed high availability of P in CPS soils, medium availability of P in the transitional zone, and low P in the MBD and SWD regions. The distribution of P fractions indicated a low degree of development of the soils, especially the MBD and SWD soils. Total P was significantly correlated positively with percentage of clay and negatively with pH and percentage of sand. Fe-P and Al-P had significant correlation with total P, percentage of sands, percent-age of clay, and available P extracted by the methods of Bray and Kurtz no. 1, Bray and Kurtz no. 2, and Truog. © 1987 The Williams & Wilkins Co.
LOGANATHAN, P, ISIRIMAH, NO & NWACHUKU, DA 1987, 'PHOSPHORUS SORPTION BY ULTISOLS AND INCEPTISOLS OF THE NIGER DELTA IN SOUTHERN NIGERIA', SOIL SCIENCE, vol. 144, no. 5, pp. 330-338.
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Phosphorus (P) sorption at equilibrium concentrations of 0.1–2 ppm in 0.01 M CaCl2 by 42 samples of highly acidic surface layers of Ultisols and Inceptisols from three major geomorphological regions of the Niger Delta of Nigeria, West Africa, conformed to the Langmuir isotherm. Langmuir sorption maxima and sorption at 0.2 ppm equilibrium P concentration ranged from 100–767 μ P/g soil and 30–240 fig μ P/g soil, respectively, indicating that the soil samples have low to medium P fertilizer requirements. No significant difference in sorption capacities among the soils of the three geomorphological regions or the two soil orders was noticed. Sorption capacities were significantly correlated with percentages of clay and silt, surface area, and different forms of Fe and Al, but not with pH or organic matter. Multiple regression equations relating P sorption to exchangeable Al, amorphous Al, amorphous Fe, and crystalline Fe are presented, and the relative contributions of these factors in the soils of the three geomorphological regions are discussed. © 1987 The Williams and Wilkins.
Miyanaga, Y, Nagai, N & Miki, N 1987, 'ARMA digital lattice filter based on new criterion', IEEE Transactions on Circuits and Systems, vol. 34, no. 6, pp. 617-628.
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NG, TMJ & HOANG, DB 1987, 'JOINT OPTIMIZATION OF CAPACITY AND FLOW ASSIGNMENT IN A PACKET-SWITCHED COMMUNICATIONS NETWORK', IEEE TRANSACTIONS ON COMMUNICATIONS, vol. 35, no. 2, pp. 202-209.
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Okita, Y, Miyanaga, Y, Nagai, N & Miki, N 1987, 'ARMA digital lattice filters based on geometric approach.', Journal of the Acoustical Society of Japan (E), vol. 8, no. 3, pp. 85-97.
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This paper discusses various ARMA digital lattice filters. The design procedures of these filters have been proposed as various forms. However, if we notice the orthogonal method based on a linear estimation theory, all design procedures are treated with an understandable coherent form. First, this paper examines the ARMA lattice filter whose section increases either AR order or MA order by one independently. The filter section is regarded as elementary. In order to derive this section, the subspace used in the orthogonal projection method is carefully processed with the other subspaces. In other words, this paper shows the implicit dependency in each elementary section. In addition, this paper develops the ARMA filter associated with the Mullis-Roberts' algorithm. This algorithm estimates the AR parameters for the ARMA reference model. Thus, it used to have nothing to do with the construction of the lattice filter. However, if an appropriate subspace is selected, we can design a Mullis-Roberts' algorithm type ARMA lattice filter. In this paper, all relations in the design procedures become clear to understand them easily. © 1987, Acoustical Society of Japan. All rights reserved.
Popolo, SD & Shannon, AG 1987, 'Some aspects of mathematical underachievement in secondary education', International Journal of Mathematical Education in Science and Technology, vol. 18, no. 2, pp. 165-175.
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The purpose of this paper is to demonstrate, in a preliminary fashion, that even though the causes are many, the dynamics of underachievement show a common core of cognitive and motivational factors which are interrelated and which are found in all underachievers. The study involved three groups of selfreferred Year 10 students of mathematics from the lower two of the four classes in the Year 10 at a Sydney high school. Although these students' assessed IQs on Australian Council for Educational Research (ACER) forms ML and MQ ranged from 98 to 130+, their performance, overall, was below expectations when the study commenced. Remedial assistance totalling six hours (nine 45-minute sessions) over a six-week period produced significant improvements in achievement as well as in self-esteem and general study habits. © 1987 Taylor and Francis Group, LLC.
PULMANO, VA, BAKOSS, SL & SHIN, YS 1987, 'A SIMPLIFIED NONLINEAR-ANALYSIS OF CONCRETE FRAMES', MAGAZINE OF CONCRETE RESEARCH, vol. 39, no. 138, pp. 29-34.
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This paper presents a simplified method for the analysis of reinforced concrete frames subjected to sustained service loads. The finite element model used takes into account the non-linearities due to cracking and the time-dependent effects due to creep and shrinkage. It is based on methods widely used by designers at present to analyse short-term linear behaviour. The method is suitable for implementation on microcomputers for applications in the design of medium-rise reinforced concrete frames. Predictions of the behaviour of laboratorytested frames are shown to be in good agreement with measured values. © 1987, Thomas Telford Ltd. All rights reserved.
Pulmano, VA, Bakoss, SL, Shin, YS & Espion, B 1987, 'Discussion: A simplified non-linear analysis of concrete frames', Magazine of Concrete Research, vol. 39, no. 141, pp. 231-234.
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ROPER, H & BAWEJA, D 1987, 'CARBONATION OF CONCRETE AND ITS PREDICTION - DISCUSSION', CEMENT AND CONCRETE RESEARCH, vol. 17, no. 6, pp. 1003-1004.
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SHANNON, AG, CLARKE, JH & HILLS, LJ 1987, 'CONTINGENCY RELATIONS FOR INFECTIOUS-DISEASES', COMPUTERS & MATHEMATICS WITH APPLICATIONS, vol. 14, no. 9-12, pp. 829-833.
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This paper outlines a discrete-time model for the spread of an infectious disease. A partial recurrence relation, which extends the Fibonacci model, is developed from a three-stage process: an immature stage; an infectious stage and a recovery stage. The approach adopted here is essentially aimed at facilitating computational procedures. © 1987.
Sleet, RJ, Shannon, AG & Irvine, B 1987, 'A systematic approach to solving closed problems', International Journal of Mathematical Education in Science and Technology, vol. 18, no. 5, pp. 705-715.
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An investigation of students' unsuccessful attempts to solve a mathematical problem is described, where the students possessed all the prerequisite skills. The results of this study are combined with evidence from previous research to propose a three-stage nine-step procedure for solving closed problems. © 1987 Taylor and Francis Group, LLC.
Song, S-M & Waldron, KJ 1987, 'An Analytical Approach for Gait Study and Its Applications on Wave Gaits', The International Journal of Robotics Research, vol. 6, no. 2, pp. 60-71.
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In the past, the determination of the gait stability margins of legged locomotion systems depended mainly on numerical computation assisted by graphical methods. Although some of these results were expressed as empirically derived equa tions, analytical derivations were lacking. The only exception was the equation of the longitudinal stability margin for quadruped wave gaits derived by McGhee and Frank (1968). They applied a complicated, nonlinear programming ap proach to the derivation. In this paper, we describe an ana lytical approach that has proved to be more efficient than previous gait study techniques. This analytical approach de fines the foot positions by means of the concept of local phase, which is the fraction of a cycle period by which the current foot position follows the placement of that foot. Based on this concept, basic theorems that simplify the study of periodic gaits are developed. This analytical approach is then applied to derive a general equation for the longitudinal stability margin for the 2n-legged wave gait. Also, this ap proach is applied to study the effects on the stability margin of the wave gait by varying the stroke and the pitch of the leg.
Song, S-M & Waldron, KJ 1987, 'Geometric Design of a Walking Machine for Optimal Mobility', Journal of Mechanisms, Transmissions, and Automation in Design, vol. 109, no. 1, pp. 21-28.
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The design of the geometry of a walking machine depends to a considerable extent on the applications for which the machine is intended. Nevertheless, there are some very general principles and approaches which may be applied. This paper deals with the geometric design of a hexapodal walking machine which is to possess optimum mobility on varied terrain. This problem both illustrates, and serves as a vehicle for, the development of these general principles. Since one of the most important features of legged locomotion is the gait, the fundamental gaits of a 2N-legged (N≥2) walking machine on both flat and irregular terrain are introduced first. The motion of the machine is assumed to be quasi-static. The mobility of a walking machine using these gaits, mainly centered on the hexapodal case, is then discussed. The principles obtained in gait and mobility studies are then applied to the design of the geometry of a hexapod, which includes both body-leg layout and leg walking volumes (working spaces), so that the hexapod may possess the optimum mobility.
Song, S-M, Lee, J-K & Waldron, KJ 1987, 'Motion study of two- and three-dimensional pantograph mechanisms', Mechanism and Machine Theory, vol. 22, no. 4, pp. 321-331.
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Vigneswaran, S & Suazo, RB 1987, 'A detailed investigation of physical and biological clogging during artificial recharge', Water, Air, and Soil Pollution, vol. 35, no. 1-2, pp. 119-140.
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An attempt was made to study the physical and biological clogging during artificial recharge with an experimental model that simulates the artificial recharging practice by considering factors such as effective infiltration rate, media size and depth, and inundation period. Recharging was investigated experimentally in terms of suspended solids (SS) removal, 3-day biological oxygen demand (BOD3) removal and chemical oxygen demand (COD) removal at different sand sizes and infiltration rates. To understand the physical phenomenon involved, the effect of suspended solids concentration and initial infiltration rate on cumulative discharge was studied and verified using a simple mathematical model. The simulated cumulative discharge profiles were comparable with the experimental profiles. This indicates that an empirical relationship can be successfully used to predict the biological clogging at different recharge rates. The effect on headloss was also discussed. © 1987 D. Reidel Publishing Company.
Vigneswaran, S & Tien, C 1987, 'Transient behavior of deep-bed filtration of brownian particles', Chemical Engineering Science, vol. 42, no. 11, pp. 2729-2739.
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A new model is proposed for deep-bed filtration of Brownian particles. The model incorporates the unit-collector concept for estimating particle deposition rates and the application of the effective medium approximation (EMT) theory for predicting the instantaneous pressure drop across the filter bed. Case studies are used to show the effects of various variables on filter performance. © 1987.
Voinov, AA & Tonkikh, AP 1987, 'Qualitative model of eutrophication in macrophyte lakes', Ecological Modelling, vol. 35, no. 3-4, pp. 211-226.
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Wang, SL & Waldron, KJ 1987, 'STUDY OF THE SINGULAR CONFIGURATIONS OF SERIAL MANIPULATORS.', Journal of mechanisms, transmissions, and automation in design, vol. 109, no. 1, pp. 14-20.
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A manipulator is at a singular configuation when the screws representing the instanteous joint motions of the manipulator are linearly dependent, and the manipulator cannot be moved along an exact path with specified orientation in world coordinates. There are infinity **3 singular configurations for a six-degree-of-freedom manipulator, and all these configurations constitute the singularity field. An algorithm is derived to trace the singularity field. Another algorithm presented in this paper finds all the joint screws reciprocal to a given wrench screw. Some new robotic applications are then possible using the principle of aligning a power tool with the screw of the reciprocal wrench.
Wang, S-L & Waldron, KJ 1987, 'A Study of the Singular Configurations of Serial Manipulators', Journal of Mechanisms, Transmissions, and Automation in Design, vol. 109, no. 1, pp. 14-20.
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A manipulator is at a singular configuration when the screws representing the instantaneous joint motions of the manipulator are linearly dependent, and the manipulator cannot be moved along an exact path with specified orientation in world coordinates. There are ∞3 singular configurations for a six-degree-of-freedom manipulator, and all these configurations constitute the singularity field. An algorithm is derived to trace the singularity field. Another algorithm presented in this paper finds all the joint screws reciprocal to a given wrench screw. Some new robotic applications are then possible using the principle of aligning a power tool with the screw of the reciprocal wrench.
Kumar, V & Waldron, KJ 1970, 'ACTIVELY COORDINATED VEHICLE SYSTEMS.', American Society of Mechanical Engineers, Design Engineering Division (Publication) DE, pp. 1-10.
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The use of independent actuation of suspension and locomotion degrees of freedom offers significant potential for improved performance vehicles. In this paper, the mathematics of active coordination of such systems is explored. Two different, actively coordinated mobility system configurations are used as examples to elucidate the principles involved.
Kumar, V & Waldron, KJ 1970, 'SUB-OPTIMAL ALGORITHMS FOR FORCE DISTRIBUTION IN MULTIFINGERED GRIPPERS.', pp. 252-257.
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The authors address the problem of the determination of the fingers of a multifingered gripper grasping an object. The system is statically indeterminate and an optimal solution for this problem is desired for force control. A fast and efficient suboptimal method for computing the grasping forces is presented. This method is based on the superposition of finger-interaction forces on equilibrating forces. An interaction force is defined as the component of the vector difference of the finger contact forces at any two fingers along the line joining the two contact points. They are computed based on the assumption that the normals at the point of contact pass through the centroid of the contact points and are therefore independent of the actual geometry of the object. The contact interaction is modeled as a point contact. The problems associated with making the algorithm independent of the object geometry are explored.
Lai, JY, Nair, SS, Singh, R & Waldron, KJ 1970, 'DYNAMIC SIMULATION AND CONTROL OF WALKING MACHINE LEG.', American Society of Mechanical Engineers, Dynamic Systems and Control Division (Publication) DSC, pp. 117-126.
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Mobility and computer control of legs is one of the most important design considerations in mobile robotic systems. Their characteristics and limitations can be studied using a mathematical simulation model. In this study, a nonlinear dynamic model of a hydraulically controlled leg of a walking vehicle is developed. It includes the leg dynamics, the actuation system dynamics, modes of operation and control aspects. Comparison of experimental data with that from the simulation shows that the model predicts the system behaviour accurately. The model has been used to study and improve system response characteristics.
Pandy, MG, Kumar, V, Berme, N & Waldron, KJ 1970, 'DYNAMICS OF QUADRUPEDAL LOCOMOTION.', American Society of Mechanical Engineers, Applied Mechanics Division, AMD, pp. 365-368.
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This study aims at providing a foundation for the understanding of the dynamics of quadrupedal locomotion. The motivation for such an undertaking is the design, and eventual construction of a fully autonomous vehicle possessing a level of agility competitive with that observed in nature. Specifically, two types of ungulate gait are analysed - a walk and a trot. The primary aim is to characterize the locomotory functions of the individual joints. To this end, video tape was used to capture the movements of the animal on level terrain. In addition, ground reaction forces were measured and a segmental free body analysis was carried out to compute the corresponding joint intersegmental forces and muscle moments. These, together with considerations of energy and power, provide the beginnings of an experimental database upon which the above goals may rest.
