No description available.

No description available.

System-on-a-chip (SoC) designs have gained immense popularity as they provide designers with the ability of integrating all components (called IPs) of an application-specific computer system onto a single chip. However, one of the main bottlenecks of the SoC design cycle is the validation of complex designs. As system size grows, validation time increases beyond manageable limits. It is desirable that design inconsistences are found and fixed early in the design process, as validation overheads are significantly higher after IPs are integrated. This thesis presents a range of techniques for the automatic verification and design of SoCs that aim to reduce post-integration validation costs. Firstly, local module checking algorithm, a practical implementation of module checking, is presented. This technique allows for the comprehensive verification of IPs such that they guarantee the satisfaction of critical specifications regardless of the SoC they are used in. Local module checking is shown to be able to validate IPs in much lesser time on average than global module checking, and can help in handling many important validation tasks much before the integration stage. Next, a number of protocol conversion techniques that assist in the composition of IPs with incompatible protocols is presented. The inconsistencies between IP protocols, called mismatches, are bridged by the automatic generation of some extra glue-logic, called a converter. Converters generated by the proposed techniques can handle control, datawidth and clock mismatches between multiple IPs in a unified manner. These approaches ensure that the integration of IPs is correct-by-construction, such that the final system is guaranteed to satisfy key specifications without the need for further validation. Finally, a technique for automatic IP reuse using forced simulation is presented, which involves automatically generating an adaptor that guides an IP such that it satisfies desired specifications. The proposed technique can generate adaptors in many cases where existing IP techniques fail. As it is guaranteed that reused IPs satisfy desired specifications, post-integration validation costs are significantly reduced. For each proposed technique, a comprehensive set of results is presented that highlights the significance of the solution. It is noted that the proposed approaches can help automate SoC design and achieve significant savings in post-integration validation costs.

One of the most important process operations in the pulp and paper industry is the transport of pulp in pipe lines. Because pipe friction losses are much higher than with water under comparable conditions, accurate design correlations for each pulp are important to the industry. The purpose of this investigation was to design and build a flow rig suitable for investigating a wide range of pulp conditions, to obtain pipe friction loss data for New Zealand pulps, and to produce design correlations and procedures for the industry. This thesis is therefore concerned primarily with describing the experimental equipment and procedures, presenting pipe friction loss data for a variety of New Zealand pulps, including a design correlation for them, and developing design methods for computing friction losses. It includes, in addition, data on drag reduction observed at high velocities of flow, and a discussion of flow mechanisms in each regime of flow. The equipment was designed to produce friction loss data from three pipe diameters simultaneously for each consistency of pulp. Flow rate was controlled without throttling the flow. Pipe friction loss data are presented for five Kraft pulps and one neutral sulphite semi-chemical pulp. Data were obtained from 1,2,3 and 4 in. diameter PVC pipes for a wide range of consistencies and flow rates up to 0.8 ft3/sec. Standard Lampen mill evaluations on hand sheets made from the pulps are presented, as well as data on the characteristics of the fibres. The Kraft pulps exhibited the characteristic maxima and minima but the semi-chemical pulp did not exhibit these turning points. For Kraft pulps head losses before the respective maxima were increased by refining the pulp and using rough pipe; and decreased by adding short-fibre Tawa and by drying and reslushing the pulp. In comparison with maxima for the unbeaten Kraft Pulp, the maxima of the head loss curves for all Kraft pulps were shifted to lower velocities by the above-mentioned operations. This would reduce the friction loss in many practical cases. In particular, rough pipe lowers the magnitude of friction loss in this regime, and can therefore yield a considerable economic advantage. A single design correlation for Kraft pulps is presented for the regime of flow before the maxima in the head loss curves. The limits of the correlation are given. Friction losses of New Zealand pulps were found to be lower than those previously reported in the literature. Two methods of design are presented for the regimes at velocities above the maxima in the head loss curves. A procedure is suggested for pulp and paper mills to obtain their own limits for the design correlation and to verify the correlation proposed in this investigation for their own pulps. A design correlation for the Tawa NSSC pulp is also presented. Mechanisms of flow are discussed for Kraft pulps and a semi-chemical pulp. Visual observations in an artificially roughened pipe for the regime of flow before the maxima of the head loss curves have confirmed fibre-wall contact in this regime. Data obtained at the first sign of permanent plug disruption have been correlated with data at the onset of drag reduction. Fully developed turbulence was found to occur at the maximum level of drag reduction. Some velocity profiles are reported for the transition regime using a modified annular-purge probe. In addition the disruptive shear stress of fibre networks has been correlated by three different methods. Data for the onset of drag reduction are presented and compared with data previously obtained from large diameter pipes from other investigations. This correlation is used as a method for designing piping systems at high flow rates.

The investigation reported in this thesis is part of a programme of research concerning the flow behaviour of paper pulp suspensions commenced at the University of Auckland in 1969. A primary aim of the research was to supply the industry with reliable pipe friction data for the pulps manufactured in New Zealand mills. Secondly, it was hoped to increase the fundamental understanding of the mechanisms of flow of the suspensions in pipes and so devise a more satisfactory method of correlation than the one used at present. Pipe friction data were obtained for two N.Z. groundwood pulps, two N.Z. Kraft pulps and one imported Kraft pulp in 1, 2, 3 and 4 inch pipes for a wide range of consistencies and velocities. The data were of the same form as previously reported in the literature, but for a given set of conditions the friction losses were lower for the N.Z. pulps. For Kraft pulps the curves of head loss versus velocity exhibited the usual maxima and minima, but for groundwoods the decrease in head loss from the maximum to the minimum and the subsequent rise were replaced by an approximately level portion. The data in the regime before the maxima in the head loss curves for Kraft pulps were correlated to allow extrapolation to the larger pipes used in the paper mill. This regime incorporates the majority of practical flow situations for consistencies over two per cent. The limits of the regime were approximately defined by values of the dimensionless friction factor. The correlation method used was a slight modification of that employed by previous authors. The data for groundwood pulps were correlated in a similar way. The head losses predicted by the new correlations were consistently lower than those calculated from previous equations. Observation of the flow in perspex pipes confirmed the mechanisms of flow proposed by some previous authors, but disagreed with the mechanisms proposed by others. The mechanisms of flow of groundwood pulps were found to be essentially similar to those of Kraft pulps except that the groundwoods exhibited a plug cleavage phenomenon at very low velocities. The different shapes of friction curve for the two types of pulp were attributed directly to their macroscopic properties. A flow model was developed on the basis of the observed flow behaviour in pipes in which the suspensions move as a fibre/water plug surrounded by a sheared water annulus. The model assumed that the annulus formed as a result of the action of the hydrodynamic shear stress on the fibre network comprising the plug. The analysis resulted in an expression relating the average velocity and the longitudinal pressure gradient in the pipe and also incorporated the pipe radius, the viscosity of the suspending medium μ and a pseudo shear modulus for the fibre network G. The plug flow model was found to apply to the data in the regime before the maximum in the head loss curve. The relation between the pressure gradient and the pipe diameter as predicted by the model was slightly erroneous for some pulps, although it was the same as that in the standard empirical correlation used in design by the industry. This led to the conclusion that the deflection of fibre ends on the plug surface also contributed to the formation of the annulus, as proposed by previous authors. The relative importance of the two mechanisms of annulus formation was used to explain the occurrence of the maxima and minima in the head loss curves for chemical pulps. The plug flow model was found to be closely related to both the direct correlation method used in the past and to the standard pseudoplastic model for non-Newtonian pipe flow. The model was also applied to analogous flow in a rotational viscometer. The values of the pseudo shear modulus G calculated from the rotational viscometry data were the same as those calculated from pipe flow data under certain conditions. However, limitations in the equipment and the effect of gravitational settling restricted the results to a narrow range. The behaviour of the pulp suspensions in batch settling tests varied markedly from pulp to pulp. There was a high correlation between the pseudo shear modulus G obtained from pipe flow data and the final height of the suspension in a settling test. Likewise there was a relationship between the effective viscosity of the suspending medium μ (as modified by the proportion of fines in the pulp) and the initial settling rate in a batch test. This suggested that a simple and accurate method of determining pipe friction data from batch settling test data is possible. Settling tests also showed that air content and the presence of acidic and basic ions, but not the viscosity of the suspending medium, increased the strength of fibre networks. A further correlation method to incorporate all flow regimes was suggested from the results of the present investigation and from indications in the literature that fibre networks behave like Bingham plastics when they are sheared.

No description available.

Linearization of RF power amplifiers is surveyed, reviewed and analyzed. Cartesian feedback is specifically presented as an effective means of linearizing an efficient yet non-linear power amplifier. This reduces amplifier distortion to acceptable levels and enables the transmission of RF signals utilizing spectrally efficient linear modulation schemes with a lower consumption of DC power. Results from constructing experimental hardware shows an intermodulation distortion (IMD) reduction of 44dB (achieving a level of −62dBc) combined with an efficiency of 42% when transmitting ð/4 QPSK. The careful amplifier characterization measurement method presented predicts performance to within 2dB (IMD) and 4% (efficiency) of practical measurements when used in simulations. A comprehensive stability analysis is developed using piecewise amplifier models within a multiple-input, multiple-output block diagram representation of the cartesian feedback loop. The analysis shows how RF amplifier non-linearity, the RF phase adjuster setting, loop gain, bandwidth and delay affect stability. A graphical interpretation of the analysis is given that indicates how stable a given RF amplifier will be when setting up a practical cartesian feedback loop. Instability is shown to result when the amount of RF phase rotation introduced by AM/PM distortion, and by setting error in the RF phase adjuster within the loop, equals the open-loop phase margin. For one of the amplifiers investigated, the analysis predicts that instability results just after the transistor turn-on region when the phase adjuster is adjusted above optimum, and instability also results at transistor saturation when adjusted lower than optimum. This is also demonstrated with experimental hardware. From the analysis, the perturbated behaviour of the non-linear piecewise amplifier model is shown to display two forms of operation when placed in a feedback loop, namely: spiral mode and stationary mode. Spiralling tends to cause the noise floor of the output spectrum to rise on one side depending on the direction of the spiral. The direction is in turn dependent on the setting of the RF phase adjuster within the loop. When the phase adjuster is in the forward path, phase adjustments lower than optimum, will cause the noise to rise on the right side of the output spectrum (anti-clockwise spiralling) and viceversa. With the phase adjuster in the feedback path the reverse is true. Loops with low stability margins are demonstrated to exhibit closed-loop peaking which can affect the out of band noise performance of a cartesian feedback transmitter. In order to achieve a non-peaking condition for a first order loop with delay, the phase margin of the loop needs to be around 60°. It is also possible to approximately predict the degree of peaking from the gain and phase margins. Further investigation of noise performance suggests the loop compensation should be placed as far up the forward chain as possible (i.e. close to the power amplifier) in order to minimize the out-of-band noise floor. This too is demonstrated experimentally. The concept of dynamic bias is also presented as a method to improve cartesian feedback efficiency. The method works by setting up optimum bias conditions for the power amplifier (derived from amplifier characterizations) and then having the cartesian feedback loop make fine adjustments to the RF drive to achieve the exact required output. This way the bias conditions do not have to be applied perfectly, implying simple (i.e low switching frequency) switched mode power supplies can be used to apply the desired collector voltage for example. The simple step-down switch mode power supply constructed achieved an efficiency of 95% at high output levels. Applying it to a cartesian feedback loop markedly improved efficiency. At an output power of 20dBm average, the linearized amplifier efficiency lifted from 45% to 67%, an improvement of over 20% and a reduction in current consumption by 33%.

In this thesis the structural analysis of two basic types of bridge deck systems are discussed: 1. the nmltibeam bridge deck II. the skewed anisotropic bridge deck. The major difficulty in the analysis of I, the multibeam deck, arises from its lack of transverse bending stiffness; load distribution occurs by shear transference at interlocking shear keys. An analysis method, developed from transfer matrix theory is proposed and shown to be satisfactory for such a structure. Model studies on a quarter scale multibeam bridge deck are described together with field tests on the prototype decks - the southern motorway bridges crossing Slippery Creek. Agreement between theory, model studies and field tests is illustrated. The satisfactory analysis of II, the skewed anisotropic deck, is complicated by its anistropic elastic properties and skewed geometry. An analysis procedure is introduced which is an extension of the finite element technique already established in other plate bending and plane stress problems. Using therefore the matrix displacement method and finite element discretization, the method has been programmed for solution by digital computer. Comparison of the computed displacements with those obtained by experiment on skewed isotropic and anisotropic steel plates is given. The finite element method is seen to be a powerful analytical tool, particularly because of its ability to handle elastic anisotropy and arbitrary geometric shapes.

The transverse vibration of a bluff body in a steady fluid flow is a phenomenon that has been observed and discussed through the ages. Named after the Greek God of Wind Aeolius, the Aeolian Tones, such as are emitted by the wind in telephone or power lines, were known to the Greeks, who produced musical sounds from an Aeolian Harp by hanging it in a current of wind. The first recorded association of the transverse vibration with a periodic wake pattern was made by Leonardo Da Vinci, who observed and sketched the process of alternate periodic vortex shedding from a bluff body to form the staggered vortex trail in its wake. It is unlikely that prior to the nineteenth century many structural failures occurred due to hydrodynamic excitation. Wood, stone and brick were the main construction materials, and the elementary design methods used were very conservative ensuring that the structure had high frequency, large mass and a large damping factor. A very high flow velocity was therefore needed to initiate structural oscillations by vortex shedding and, if initiated these structural oscillations would usually be quickly damped out. During the nineteenth century the rapid advancement in the art of civil engineering design and the introduction and development of concrete and steel as a construction material led to the design of streamlined structures with more economical dimensions and consequently lower frequencies, smaller masses and smaller damping factors. Although design codes made a reasonable allowance for static loadings, dynanic loadings caused by earthquakes and hydrodynamic excitation were eirther ignored or underestimated.

Specimens of high-density low-density polyethylene were uniaxially compressed at nominally constant strain-rates ranging from 0.000066 to 0.66 sec-1 at temperatures from 77° to 350°K and hydrostatic pressures from 0.001(latm) to 4 K bar. It was shown that there were significant effects of temperature, pressure and strain rate on both polyethylenes. At small strains (O.O1), the time-temperature and time-pressure superpositions were used successfully to construct the master curves of stress versus reduced strain-rate. These master curves, which were found to have been taken in the range of linear-viscoelastic behaviour of the polymers, were employed to derive the stress-relaxation moduli and the relaxation spectra. The viscoelastic response to temperature and pressure of high-density polyethylene in the transition zone between the γ and α relaxations, and that of low-density polyethylene in the transition zone between the γ and β relaxations have been found to be controlled by the same molecular motion. This motion, an Arrhenius-type activated process, was identified as involving molecular segments of six to eight carbon atoms with an activation energy of 22 Kcal/mole and an activation volume of 110 cm3/mole.