Regular Stream Research Articles

Resonance penetration of gas bubbles through a thin liquid layer: a capillary resonator and its use for the generation of droplets

As it is well known, a bounded layer of liquid forms an oscillatory system (resonator) for surface waves. We consider a capillary wave resonator that is composed by a thin liquid layer placed on a substrate and surrounded by a solid ring. The dimensions of the system are chosen so that gravity forces are small compared with forces from surface tension. Standing capillary waves are excited by a gas flow supplied through a small orifice in the substrate. Stable oscillations in various resonator modes are described which are accompanied by ordered formation and destruction of gas bubbles producing the regular streams of identical droplets. The mechanism of self-oscillatory behaviour based on the correspondence between bubble growth time and oscillation period is proposed and analysed. Possible applications of the phenomenon, in particular, for the generation of monodisperse droplets without special periodic stimulation, are discussed.

Measurement and Analysis of Laboratory Generated Steep Waves

In many offshore locations, storm generated steep waves are common and the survival of offshore structures in their presence is an important design condition. The design environment in depth-limited waters often includes waves of breaking and near-breaking conditions, in which currents may be present. Experiments were carried out in a wave tank with simulated steep waves with and without steady in-line current in which the wave profiles and the corresponding kinematics were simultaneously measured. The waves included both regular and random waves and often approached the breaking wave height for the water depth. These waves were analyzed by higher-order wave theory. In particular, the regular waves were simulated by the regular and irregular stream function theory. Especially steep wave profiles within the random waves were computed using the irregular stream function theory. The theory allows inclusion of steady current in its formulation for computation of wave kinematics. The correlation of the measured wave kinematics with the higher-order stream function wave theory showed that the wave theory could predict the kinematics of these steep waves (with and without the presence of current) well. However, in breaking waves, the vertical water particle velocity was not predicted well, especially near the trough. The effect of breaking and near-breaking steep waves on a fixed vertical caisson was also studied. The forces measured on the vertical caisson from the wave tank testing were analyzed to determine the effect of these waves and currents on the forces. It was found that the measured forces (and overturning moments) on the caisson model matched fairly well by the proper choice of force coefficients from the design guideline and the nonlinear stream function theory of appropriate order.

Investigation of Shallow Water Kinematics and Local Loading Effects on Reliability of Minimum Structures

In shallow water, and specifically for minimum structures, the critical wave height exponent α has been shown to vary significantly with structural configuration. Because of the strong relationship to the wave kinematics, α is also sensitive to the wave theory chosen. The North West Shelf offshore Australia has numerous minimum structures located in relatively shallow water, which requires non-linear wave theory. In the near-breaking condition, estimation of the wave crest kinematics is difficult, with Stream Function theory being the most widely used. However, various other wave theories and nonlinear numerical techniques have been developed to predict wave kinematics for shallow water conditions. The following wave theories are compared: regular Stream Function theory, Cnoidal wave theory, Stokes’ theory, NewWave theory, and a second-order correction to NewWave theory. Kinematics, loads and α results are presented for a cylinder in three different water depths.

Local systemic intervention

This paper reviews Local Systemic Intervention (LSI). LSI results from learning about Total Systems Intervention (TSI). Learning followed application of TSI and by putting TSI through a postmodern critique. LSI is a complementarist approach. It encourages diversity through local decision making about the relevance of designs, consideredness of decisions and astuteness of judgements. It encourages developing discourse around these three centres of learning and designing action accordingly. There is a regular stream of applications of LSI in many types of organisations.

Super-Streaming: A New Object Delivery Paradigm forContinuous Media Servers

A number of studies have focused on the design of continuous media, CM, (e.g., video and audio) servers to support the real-time delivery of CM objects. These systems have been deployed in local environments such as hotels, hospitals and cruise ships to support media-on-demand applications. They typically stream CM objects to the clients with the objective of minimizing the buffer space required at the client site. This objective can now be relaxed due to the availability of inexpensive storage devices at the client side. Therefore, we propose a Super-streaming paradigm that can utilize the client side resources in order to improve the utilization of the CM server. To support super-streaming, we propose a technique to enable the CM servers to deliver CM objects at a rate higher than their display bandwidth requirement. We also propose alternative admission control policies to downgrade super-streams in favor of regular streams when the resources are scarce. We demonstrate the superiority of our paradigm over streaming with both analytical and simulation models. Moreover, new distributed applications such as distant-learning, digital libraries, and home entertainment require the delivery of CM objects to geographically disbursed clients. For quality purposes, recently many studies proposed dedicated distributed architectures to support these types of applications. We extend our super-streaming paradigm to be applicable in such distributed architectures. We propose a sophisticated resource management policy to support super-streaming in the presence of multiple servers, network links and clients. Due to the complexity involved in modeling these architectures, we only evaluate the performance of super-streaming by a simulation study.

ATLAS PROJECT: An incentive to reach an ecological, demographic and economic balance in the mediterranean region

The International Institute for the Study of Man has promoted a research theme charged with a project of reforestation of the Atlas Mountains to be proposed to the E.C.The Atlas Project relies on three fundamental assumptions:a. there is the need to build CO2 sinks that, at the same time, are a source of energy and income in regions from which, due to the lack of both, vast migratory flows start. The state members of the European Community are not able to absorb the quantity of CO2 produced by industrial combustion, the heating system and cars, and they still do not follow the international agreement on pollution control;b. a regular stream of air from Northern Europe discharges its humidity on the Atlas Mountains, before it re-ascends over Europe. This stream of air could be a natural carrier for conveying and immobilising the CO2 produced in the industrial regions of Europe through its fixation in timber on the Atlas Mountains before it re-ascends over the European continent;c. the Moroccan area, and North Africa in general, are the source of a large number of immigrants into Europe due to the high population pressure and the lack of employment.

Particle mass distribution in the new Perseid 1987–1994 filament

Observations of the Perseid meteor stream in the period 1987–1994 were characterized by an appearance of a new filament the maximum activity of which was found near solar longitude L ⊙ = 138.9° (eq. 1950.0). Its activity culminated in 1993 while 1991 and 1995 observations showed no abnormal increase of meteors in that region. The mass distribution within the new filament has been studied in the interval 138.62° ⩽ L ⊙ < 139.10° during the period of its activity and compared with analogous results from 1958–1986, 1991, and 1995 within the same L ⊙ interval. The mass distribution indices, s, for overdense radio-meteor echoes associated with the new filament show slightly lower values comared with those determined during the activity of the regular stream.

Perceptual attenuation of nonfocused auditory streams.

The aim of this study was to measure the perceptual attenuation, measured in decibels, resulting from the focusing of attention on one stream within a multistream auditory sequence. The intensity of a nonfocused stream was increased until the accuracy of detecting a temporal irregularity in this stream was the same as in a focused stream. Eight subjects were required to detect a temporal irregularity created by delaying or advancing one tone which could be situated in one of three temporally regular streams played simultaneously to create a multistream sequence. The three streams differed in tempo and frequency. Subjects' attention was focused on one of the streams by preceding the multistream sequence with one of the single streams (a cue). We first established the size of temporal irregularity detected at a 90% level in cued streams, confirming that subjects were able to focus on one particular stream. Second, an irregularity of this size was not detected above chance level in noncued streams, demonstrating that listeners focus only on the cued stream. Third, for 5 subjects, a 15-dB increase in the level of one of the noncued streams was necessary to bring detection up to that found in the cued streams. This gain provides an equivalent measure of the perceptual attenuation of nonfocused streams. For 3 other subjects, detection in the noncued stream remained at chance performance whatever the level. For all subjects, detection in the cued stream decreased slightly as the level of the noncued stream increased. We conclude that the attenuation of nonfocused auditory streams can attain as much as 15 dB, at least for some subjects.

Rate-optimal schedule for multi-rate DSP computations

In this paper we present a novel framework ofmulti-rate scheduling of signal processing programs represented by regular stream flow graphs (RSFGs). The main contribution of this paper is translating the scheduling problem of RSFGs into an equivalent problem in the domain of Karp-Miller computation graphs. A distinct feature of our scheduling framework--called themulti-rate software pipelining--is to allow maximum overlapping of operations from successive iterations, subject only to precedence constraints caused by data dependences. p ]We demonstrate that the scheduling of regular stream flow graphs can be formulated as a mathematical problem by capturing data dependences between two actors as a precedence relation between the firing of these actors. Using linear schedules, the problem is further translated into a linear program formulation. An efficient solution for the linear programming problem is obtained by first constructing what is called theprecedence graph. A polynomial-time solution is obtained by observing that the optimal computation rate is theminimum cost-to-time ratio cycle (MCTRC) in the precedence graph and using the well-established solution methods for the MCTRC problem. Finally, to minimize the buffer requirement for the obtained rate-optimal schedule, a graph coloring method based on thecyclic interval graph representation has been proposed.

10 Gbit/s data switched semiconductor laser amplifier nonlinear loop mirror

Error-free optical modulation of a regular stream of data pulses at 10 GHz by optical data at 10 Gbit/s is demonstrated using a semiconductor laser amplifier within a loop mirror. This is achieved without patterning despite an amplifier recovery time of several bit periods by positioning the amplifier near to the centre of the loop. This approach removes sensitivity to the optical polarisation of incoming data.

Cortical Cells Should Fire Regularly, But Do Not

When a typical nerve cell is injected with enough current, it fires a regular stream of action potentials. But cortical cells in vivo usually fire irregularly, reflecting synaptic input from presynaptic cells as well as intrinsic biophysical properties. We have applied the theory of stochastic processes to spike trains recorded from cortical neurons (Tuckwell 1989) and find a fundamental contradiction between the large interspike variability observed and the much lower values predicted by well-accepted biophysical models of single cells.

Spiral Detection of Periodicity and the Spiral Form of Musical Scales

The purpose of this paper is to suggest that the neural part of the auditory system employs a temporal mechanism, referred to as a spiral processor, to determine whether sounds are periodic, and that this type of mechanism would explain the form of consonance observed in Western music. Pitch is our perception of periodicity in a sound wave, and harmony is the set of rules that explain which pitches go well together. The octave, the diatonic scale and its modes are the basic ingredients of harmony in Western music. For over a hundred years we have known that the logarithmic spiral (base 2) provides a good description of the cyclic aspect of musical scales, that is, the octave. But the implications for the internal structure of the octave, that is the diatonic scale and its two main modes, have largely been ignored. A periodic sound like a musical note generates regular streams of pulses in primary auditory neurones. As these pulse streams flow through the spiral processor they form a pattern of spokes radiating from the centre of the spiral. The shape of the pattern is fixed; the orientation of the pattern determines the pitch. The primary intervals of the diatonic scale are produced by pairs of notes whose main spokes coincide, and the intervals fall naturally into two groups, major and minor.

Russell on Arbitration (Twentieth Edition) by Anthony Walton QC and Mary Vitoria, Barrister

Russell on Arbitration, Twentieth Edition, by Anthony Walton QC and Mary Vitoria, Barrister (London, Stevens & Sons, 1982, viii and 602 pp:, inclusive Statutes, New York Convention 1958, RSC, Forms and Index ). Hardback £51. Russell is a hallowed text. None is more familiar to the English and Commonwealth commercial practitioner. It has reposed on the bookshelves of lawyers and nestled in the grasp of counsel for some 136 years. The first edition, by the initial author whose name the text carries, appeared in 1849 and since its launch there has followed a regular stream of new editions, no doubt reflecting both the popularity of Russell and the importance of the subject with which it is concerned. It is now in its twentieth edition and under the senior editorship of Anthony Walton, QC, who has been associated with Russell since 1957, and is now for the first time assisted by Dr Mary Vitoria. In the UK (but less so in Scotland) and many of the common law jurisdictions Russell is synonymous with the institution of arbitration, at least from the legal perspective. It is teacher to the apprentice, aid to the lawyer, friend to the advocate and endorsing authority for the judge. It has been so frequently cited in the judgments of the judiciary that one is readily led to speculate that it is probable that no text has been more frequently cited and adopted by the English judiciary, and this is all the more remarkable when the reluctance of the English judiciary even to acknowledge secondary authority is recalled. But the legal profession is not the sole beneficiary. The benefits have extended more broadly into arbitral practice and no arbitrator worth his salt can be unaware of the counsel to be gained from a perusal of Russell . Against this historical background and establishment acceptance a reviewer of Russell tends to approach the task with awe. But if there is cause, and regrettably there is, the courage must be mustered to …

A temporal model of pitch perception based on spiral periodicity detection

The logarithmic spiral (base 2) offers a simple passive means of detecting the regularity observed in the streams of nerve pulses produced when phase locked fibers respond to periodic sounds. That is, if time is wrapped into a spiral with time zero at the spiral's origin, then when nerve pulses‐flow outwards along the path of the spiral, the pulses of a regular stream will coalesce onto spokes emanating from the center of the spiral once per cycle. The spoke pattern has a fixed shape and it rotates around the spiral as the periodicity of the pulse stream varies. Secondary units can be used to detect coalescence on spoke patterns with specific orientations and so convert the temporal pitch information into spatial pitch information. The spoke pattern completes one revolution as the pulse rate rises or falls an octave, and the primary intervals of the Just diatonic scale produce the simplest combined spoke patterns. Thus, the logarithmic spiral provides a basis for a temporal model of pitch perception which can also predict musical harmony.

Parent Participation within an Independent School

“It has been typical within the history of special education, particularly in the area of learning disabilities, that the motivation and emphasis for program development has come from parents and their organizations rather than from educators” (Baldauf, 1980, p. 179). The Special Education Centre at Christ Church Grammar School is no exception as it was established as a result of the vocally expressed needs of parents. Prior to its inception, there was a remedial class in the preparatory school, the then Headmaster, Mr. P. M. Moyes, being firmly committed to education for the less able as well as the academically able. Parents who wanted boys enrolled at the school, and those who wanted sons from the remedial class to continue their education at the school, pressed for the establishment of a special centre. Funding was available from the Commonwealth Government and from the private sector.The Centre is an integral part of the regular school, based on a model of integrated education at primary and secondary levels. A committee consisting of the Headmaster, the headmaster of the preparatory school, the director of the Centre and, of recent years, the school counsellor, decides placement in the Special Education Centre. These placements are made after consideration of the psychological, medical and educational documentation accompanying each application, and with regard to keeping a balance of ages and grades within the Centre. Selection is dependent on the applicants satisfying the criteria for special education as opposed to remedial education. Priority is also given to country boys needing special education and boarding facilities where no appropriate alternatives are available to them. It must be felt that the programme and facilities available are likely to benefit the applicant. There are 16 full-time places available. Some boys are able to pursue certain subjects with their regular school peers. Some boys are placed into the regular stream after a period of time in the Centre. These boys then receive continuing support in their area of specific need. I have worked in the Centre as its director for five years.

Unstable flow of amorphous polymers through capillaries I. Velocity profiles of polymer having discontinuous flow curve

AbstractCiné film was employed for recording the movement of tracer particles, thus directly determining the velocity profile in the capillary flow of model materials of polybutadiene over a range of shear stresses relating to (1.) flow conditions in which there is no distortion of the regular stream of melt emerging from a capillary, (2.) severe surface fracture, (3.) elastic turbulence, (4.) oscillatory flow of melts with discontinuous flow curves. No qualitative difference was found between the velocity profiles in conditions (1) and (2); surface fracture is not related to laminar flow disturbances and originates at the capillary exit. Surface fracture must be distinguished from elastic turbulence. The streamline velocities undergo both local and time variations within the capillary under conditions of developed elastic turbulence; the wall velocity is non‐zero. A periodic pulsation of velocities occurs in the flow curve discontinuity region; it takes place throughout the capillary and is caused by stick‐slipping of polymer on the capillary wall. The frequency of velocity pulsations coincides with the frequency of extrudate variations.

A dry valley at Onich, Inverness-shire

The attention of travellers from Ballachulish to Fort William can hardly fail to be attracted by a very narrow and steep-sided valley the mouth of which crosses the main road about 300 yards south-east from Onich U.F. Church. This valley, although such a conspicuous feature in the landscape, is entirely lacking in any regular stream, being, in fact, a remarkably perfect example of a dry valley. Its mode of origin, moreover, can be clearly demonstrated. The valley runs inland from the main road in a north-easterly direction towards the present course of the Amhainn Righ, from which it is separated by a hummocky ridge, and has a total length of three-quarters of a mile. The breadth of the valley floor never exceeds 100 yards and is usually much less. The valley has been hollowed out in the Appin Quartzite series which dips south-east at a high angle. Thus on the north-west or dip slope of the valley there is a long cliff, nearly 100 feet high in places, formed of huge glistening quartzite slabs, while on the opposite or scarp side, where there was a tendency to overhang, a scree slope has accumulated which is now overgrown by brushwood and small trees. The floor slopes very gradually from sea-level up to the hummocky ridge at the valley head where there is an abrupt rise, and it seems necessary to postulate the former existence of rapids or a waterfall at this point. In section the valley is V-shaped and glacial striae