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This article investigates the application of minimal-total-processing-time (MTPT) scheduling disciplines to rotating storage units when random arrival of requests is allowed. Fixed-head drum and moving-head disk storage units are considered, and emphasis is placed on the relative merits of the MTPT scheduling discipline with respect to the shortest-latency-time-first (SLTF) scheduling discipline. The results of the simulation studies presented show that neither scheduling discipline is unconditionally superior to the other. For most fixed-head drum applications, the SLTF discipline is preferable to MTPT, but for intra-cylinder disk scheduling the MTPT discipline offers a distinct advantage over the SLTF discipline. The computational requirements of an algorithm that implements the MTPT scheduling discipline are shown to be comparable to SLTF algorithms. In both cases, the sorting procedure is the most time-consuming phase of the algorithm.

Capacity Increase of Starch Centrifuges by means of Siphon Drum. The operating method of a centrifuge drum with rotation siphons is described as the thus possible increase of filtration output. In addition, the use of the siphon drum when centrifuging maize starch are commented on. Due to the rotation siphon at the centrifuge drum and by means of a liquid sucking device to be swung into the siphon, the liquid level in the rotation siphon can be lowered to such an extent that below the filter cloth a considerable suction effect is caused. Thus the filtration speed may be increased by 50 to 300% according to the product and the capacity of the centrifuge is considerably increased due to the thus possible shorter cycle times. In the case of maize starch the filtration output can due to the rotation siphon be increased by the 1.7 to 2 fold. The overflow process used at present reconvey a considerable part of the starch milk into the preceding process. In order to avoid this, the discharge process was taken up. For this process the drum is filled but once up to rim as quickly as possible. After a short sedimentation time the liquid descharge device is swung into the drum and the clarified liquid is discharged within a short time. Subsequently, the siphon drum causes a very quick dry sucking of the starch layer in the drum, so the centrifuge may after a short time be discharged.

— Two pianists and one percussionist performed a number of notated rhythms on the piano and on the side drum or the bongo drum. The tape-recordings of the performances were analyzed by an analyzer for mono-phonic sound sequences as regards the durations and the amplitudes. Several characteristic deviations from the norms implied by the musical notation appeared. The recordings were used as stimuli in experiments on rhythm experience described elsewhere.

Experimental results for the influence of operating variables on the mean and variance of the residence time distribution for material transport in a continuous rotary drum are described. The variables considered are drum rotational speed, drum inclination, feed rate of material and particle size of material. A stimulus-response technique based on an impulse of a colored tracer, otherwise identical to the bulk material, was used. The validity of the axial dispersion model for the description of the behavior of this non-segregating transport system is demonstrated. This is accomplished with an approximate form of the exact solution to the axial dispersion model for an impulse input; it is valid for the relatively large values of the Peclet number characteristic of the experimental system.

Formulas relating the rate of filtrate flow in a sectioned disk filter to the process variables are derived. It is demonstrated that an optimum inner radius which yields a maximum flow of filtrate can be chosen. Flow rates for drum and disk filters operating under similar conditions are compared.

The white yam Dioscorea rotundata Poir was characterized, drum dried to different moisture levels, and stored at temperatures of 21.l °C, 29.4 °C and 37.8 °C for 90 days. Fresh and stored samples were analyzed for changes in color, ascorbic acid and organoleptic qualities. Freshly dried and reconstituted yam flakes were judged highly acceptable compared to conventionally mashed fresh yam and retained acceptability through storage. The taste panel consisted of persons from several West African countries. Changes in the flakes during storage are described.

The problem of multi-layered belts in large bending, around a circular drum, is studied. The belts are assumed to be made of thin, stiff-plies with soft rubber interplies. The equations governing the system are derived and the solution procedure presented. Some numerical results are given for the special case of a sandwich belt and these are compared with those obtained from classical beam theory.

Factors influencing the longitudinal variation of water level in the drums of circulating boilers are discussed with reference to the results of cold-circulation trials performed on a 500 MW assisted-circulation boiler. Numerical computation and small-scale model tests in support of the field trials are also presented. This information, together with evidence from further work on the operating boiler, has shown that small cold-water models provide an accurate analogue of drum operation at working pressures and temperatures.

This paper is concerned with a numerical analysis of visco-elastic shells of revolution under unsymmetrical loads. The numerical method of elastic analysis of shells of revolution developed by Budiansky is extended to deal with a wide range of visco-elastic problems of the quasistatic type. The visco-elastic behaviour of a material is represented by a 4-parameter model. As a numerical examples two problems of a cylindrical shell and a conical drum composed of multishells subjected to stepwise displacements with respect to time are analyzed.

This simply built device for shipboard use incorporates a tilt adjustable 57-liter drum and an effluent collector of high density polyethylene. The nonmetallic construction removes possible sources of heavy metals contamination; an enclosed elutriation drum top helps prevent spillage.

The most characteristic features of the open-end spinning compared to the ring spinning are in the drafting and twisting mechanism. In the present paper, some discussion will be made on the analysis of the drafting and twisting processes in MS-400 open-end spinning and their relation to the properties of its spun yarn. The mechanical characteristics of MS-400 are; (1) Roller drafting device (2) Ejector for fiber separation (3) Special eyelet, a yarn guide attached to the axis of the drum. These mechanisms make MS-400 a suitable spinning machine for man-made fibers. In the first part of this paper, the behaviour of fibers in the ejector separated into individuals from a fiber bundle by the air stream will be considered. The discussion will be extended on the degree of fiber separation and the state of fibers, such as straightness at the outlet of the ejector. The second part deals with some mathematical analysis of the process of fiber collection in the drum and its self-doubling effect on the yarn irregularity. It is shown that the self-doubling effect is extremely useful for decreasing the yarn irregularity of short wave length and for improving the blend uniformity of fibers in the yarn. In the third part, the effect of the eyelet equipped in the drum is considered. The eyelet is shown to have a great influence on the yarn strength and on the end down in spinning. In the last part, a brief mention will be made on the spinning features obtained by the practical production in MS-400.

Several studies on the flow pattern of particles in a horizontal rotary cylinder have been published. However, most of them dealt with the experimental explanation only. In this report, behavior of particles was investigated from viewpoint of dynamical and geometrical correlation, and a model concerning to the particles flow was provided for estimating the breadth of upward and downward flow, and the average circulation time at a cross section by giving such data as the internal friction coefficient μ of particles, the dynamic repose angle β at cascading, and the operating condition of cylinder.Moreover, the variation of bed depth along the drum axis and the hold up in it were also correlated on the basis of the theoretically derived circulation time of particles flow at a section of the drum.

A drum-scanning microdensitometer has been automated with a minicomputer equipped with a magnetic disk memory. Part of the disk is used for temporary data storage, in a manner allowing rapid retrieval. X-ray diffraction photographs from macromolecular crystals can be measured at rates up to about 25 reflections per second, with the flexibility of an `on-line' system. The method can also be used when the computer is time-shared, but with lowered film-processing rates dependent on the number of `simultaneous' (time-sharing) users.

A drum of 12 inch diameter and 3 inch width containing two kinds of spherical balls was rotated and the segregation of balls along the cross-section of the drum was investigated. Plastic, glass and steel balls of 6.0, 12.5 and 15.3 mm diameter were used.In order to measure the segregation of balls quantitatively, a segregation parameter, S, was defined.Under the conditions of identical density but different diameters, the smaller balls were found to segregate. In the case of different densities but same diameter, the heavier balls tended to concentrate inside the bed. When the heavier, larger size balls and the lighter, smaller size balls were mixed, better mixing was observed. S was also found to change with the volume fraction of the heavier balls.Empirical equations which represent the relationship between S and the experimental conditions, such as diameter ratio, density ratio and volume fraction of the heavier balls were derived. Resume Les auteurs utilisent un tambour rotatif de 12 po. de di...

The Anlo (Eve) dance drumming orchestra of southeastern Ghana has three components, each with its own general level of pitch. In the highest range idiophones and the smallest of the drums play unchanging ostinati that provide the gait of the music. One of these high instruments controls the timing and placement of all patterns. In the middle range one or more drums support the musical gait of the upper range but with varied patterns. This intermediate drumming is also usually responsive to the third component, the leading drum (or master drum), which plays intermittently in the lowest range. Some of the play of the leading drum is decorative; some controls the performers with signals

This paper discusses how a magnetic storage drum may be used for the handling and processing of analogue data. The device described has a wide field of application in data recording, and possesses some unique features rendering it a valuable tool in analogue computation.

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This paper analyzes the performance, for a particular strategy, of a head-per-track type auxiliary storage system in a real-time environment. The prototype system of either fixed-head disks or drums incorporates a hardware queuer. This device attempts to always select first that request for a data transfer which will incur the shortest rotational latency relative to all other possible waiting file access requests. The queueing analysis is concerned with the tradeoff which is experienced in practice between throughput of a stochastic service device and the response time for each service request. An exact analysis of the system is shown to be totally unmanageable. Therefore, the approach is to estimate the results via physical arguments. We obtain an approximate stationary distribution for the waiting time of a file access request in the system.

The dugga or the left‐hand thabala is a companion drum to the right‐hand thabala and the two together are widely used in India. The vibration characteristics of the latter which has a symmetrically loaded membrane were discussed previously where it was shown how this drum produces harmonic overtones.The left‐hand thabala also has a loaded drumhead, but the loading is here eccentric. The boundary value problem of this drumhead is not separable, and hence there is no readily available method for computing its characteristic frequencies. An approximate theory for computing the frequencies of the lower modes is here developed under the assumption that for these modes the effect of the (unloaded) annular region on the loaded region may be replaced by a suitably determined elastic support around its boundary. This leads to the boundary value problem of a membrane with an elastic boundary support whose stiffness constant per unit length is a function of the polar angle. The problem is still unseparable, but the ...

There are exactly four types of Tsonga drum, and four types of bow, and the prevalence of their sounds in Tsongaland outweighs that of any other musical instrument. The former are played mostly by women, the latter mostly by men, and the social role of each instrument is in sharp contrast to that of the other

In order to make clear the high tone loss after the tympanoplastic operation, the central perforation or the perforation around the manibrium mallei was made on the cats' ear drum, and then the losses of the cochlear microphonics through the perforation were measured, and compared each other.About 10dB more losses at the high frequency tones (4000-8000cps.) was recognized in the cases of the perforation around the manibrium mallei than in the cases of the central perforation.From our past studies on the mechanism of the sound conduction of the middle ear, this was concluded as follows:The drum membrane is stretched tightly between the short process and the umbo of the manibrium mallei and kept cornally by manibrium. The lack of this part makes decrease the stiffness of the drum membrane and the total sound conducting mechanism, and it diminishes the activity of the hightone conduction mechanism of the drum membrane.

Section 1 deals with the electrical design of open-circuit windings on the high-voltage machines used in connection with arc lamps in series; and the Brush open-circuit generators. The small hand-driven generators used in insulation-testing sets are also mentioned. Attention is drawn to the fact that interpoles were not introduced before these designs were superseded. Closed-circuit windings are dealt with, and it is pointed out that ring windings have gone out of use except for the special cases mentioned. The drum winding is then discussed. Section 2 deals with mechanical design. Section 3 treats of the effect of the number and dimensions of the core slots in relation to various aspects of the design. Attention is drawn to the effect on commutation of slots containing coils of various numbers of turns. Mention is made of the points to be noted in selecting the number of slots and coils. Section 4 deals with limiting factors in design. Section 5 shows how the ratio of diameter to length of armature for the minimum inductance of coil is deduced, and draws attention to the loss due to inductance. Section 6 treats of the effect of coil pitch on both commutation and armature reaction. General formulae are given for the period of commutation. Section 7 discusses special connections and their use in increasing the number of commutator bars, and draws attention to the factors limiting the output of direct-current machines. Section 8 deals with the factors affecting the electrical balancing of windings. Section 9 discusses windings for special purposes.

An examination is made of a new storage system proposed for use with digital computers and data processing equipment. This system, which utilizes a metal drum coated with a thin layer of a dielectric material, would employ two distinct methods of storage and could be used to fulfil a wide range of functions connected with computing and associated devices. The first of the proposed methods of storage would be in the form of charge patterns on a dielectric surface, and could probably be used to store data for periods ranging from milliseconds up to a few hours, while the second method, which is intended for long term storage, would be by means of internal polarization of the dielectric.

Use of two drums in tight-loop type of film-drive filter system solves the problem of film support in magnetic recorder-reproducer utilizing two separate magnetic head assemblies. Performance of filter system is analyzed.

Static charge produced by friction between the skin and cloth or clothes each other was measured. The matarial was chiefly clothe of textile yarn, it was cut to a test piece 6 × 6 cm and fixed around the edge of a drum. With the test piece fixed on the drum the skin or the cloth was rubbed, and the charge then produced on the test piece was measured. The results were summerized as the following.1) The static charge produced by friction of the skin with the test material made of textile yarn, the clothes made of which contact with skin in daily life, measured some what largevalue about 10-20 volt with positive or negative sighn.2) The charge produced by reciprocal friction of the test materials, the clothes made of which does not contact with the skin directly, measured about 20-30 volt, when one of it was textile yarn.These results were discussed and the conclusion was derived that the charge produced when the clothes was put on wear in daily life was not measured exactly but would not be so large as to affect upon the physical condition even if the clothes would produce static charge of some value when it was weared.

A freshwater drum (Aplodinotus grunniens) specimen from postglacial deposits of northern Ontario indicates the species former presence in Lake Barlow–Ojibway. The fact that the species survives in Lakes Abitibi and Timiskaming may be best explained by its having entered Lake Barlow–Ojibway from the west during the Gimli phase of Lake Agassiz about 8000 years ago, but this hypothesis cannot be confirmed with the existing evidence.

In the SNAP reactor development program at Atomics International,* a family of lightweight nuclear reactors is being optimized for space applications. Because the compact reactor is small and light in weight, components must operate without auxiliary cooling devices, thermal barriers, heat shields, and radiation shields. The components function in the environments of ultra-high temperature, nuclear radiation, and outer space for long periods of time. Control-drum actuators have been developed which will operate with high reliability in these environments.

Expressions for the temperature rise in drum and disc brakes are given for both single stops and regular repeated applications when cooling is taken into account. It is shown how these expressions enable the area of the braking path to be calculated if the temperature is not to exceed a specified value. The effect of the dimensions and the thermal properties of the brake components on the rate of temperature rise and on the limiting temperatures reached during a series of applications is discussed. Finally it is shown how random braking can be reduced to equivalent cyclic applications, and the braking area of a small sports car being driven in the Alps is calculated.

Since the past study it has been stated that different hearing effects occured whether the sound stimuli were given from a distant loudspeaker or a telephone receiver. This phenomenon will be explained from the different effective impedance of the ear, which is altered by the outer orifice of the meatus opened or not. And when there is a perforation on the drum membrane, the alteration of the impedance of the sound transmission system is added, and this will make the effect of the sound stimulus more remarkably. Upon these considerations, the model ear experiment, the animal experiment and the clinical hearing tests were pursued. The results are summarized as follows: (1) Both the minimum audible thresholds measured by the receiver method (a coupler method) and the speaker method (a free field method), showed some more reduction for the low tones below 1, 000cps. by the perforated drum membrane than by the none-perforated one, and an about 10_??_15db more loss existed by the receiver method than by the speaker method. (2) The difference between two methods was considered as due to the acoustical leakage according to the perforation of the drum membrane. (3) Therefore, when we considered the true hearing of a patient with a perforated drum membrane, the result of the hearing test with the telephone receiver must reduced be some db, especially in the range of low tones. (4) There was scarcely found any difference in the audiograms between the two methods, if there was no perforation. But it was suggested that some indirect bone conduction might exist at the severe conductive deafness. (5) The above results were affirmed also by some theoretical considerations.

An extension of an earlier model of the WRITE process in saturation recording that accounts for internal fields due to magnetization divergence in the recording medium is presented. It is shown that the initial condition of the medium determines the internal field distribution during WRITE and may lead to appreciable peak shift and WRITE over modulation. The special case of two successive reversals of magnetization for a dc biased recording medium is considered in detail. System design criteria for optimization of the recording medium parameters, the head pole gap, and the WRITE time constant are presented for a system where the remaining parameters are constrained. Calculation for the initial and quiescent magnetization and internal field and the expected signal trace, in addition to experimental data, are presented for an out-of-contact drum system employing a NiZn ferrite WRITE-READ head and a CoNiP plating.

1. The tensiometric method of investigation shows that the agreement between theoretical and experimental data is satisfactory. Consequently, the assumptions which have been made on designing idle drums with a flat disk* can be accepted: a) the drum is rigidly mounted on the shaft; b) the width of the belt is equal to the distance between the supporting disks; c) the part of the shell protruding beyond the limits of the supporting disks can be ignored. As a result, the interaction between the disk and the shell can be represented by the contour forces. The latter assumption is confirmed by an additional investigation of the stress condition of the protruding shell parts. 2. The discrepancy, noted for a number of points, between theoretical and experimental data is due to the error obtained by using this method if the level of stresses is not high and by averaging the strains over the length of a pickup. This is particularly noticeable for points with a high stress gradient. 3. The asymmetric and nonuniform application of load over the length of the drum on the side of the belt hardly distorts the picture of its stress condition.

A description is given of a new time switch for use on alternating current circuits and in which a Warren synchronous motor is employed to drive a timing drum. The timing drum makes and breaks a relay circuit used in the present case for controlling the supply to an X-ray installation. A wide range of controlled periods is possible with the arrangement. Some applications of the instrument are suggested.

A technique for producing accurate models is described. The models were subjected to internal pressure and the displacements of points on the outer surface were measured with a travelling microscope. From these measurements the radii of curvature and the rotation of the elements were determined graphically and the bending moments calculated. The greatest bending moments were found to be proportional to the percentage increase in head height and almost independent of Poisson's ratio of the material except for the change in flexural rigidity. The effect of large strains on the bending moments in any drum head can therefore be calculated if the relation between increase in head height and pressure has been determined and the bending moments for one pressure are known.

Japanese Industrial Standard, M 8801-4963 (Methods for testing of coal) and K 2151-1963 (Methods for testing of coke) were partly revised and published under the authority of the General Committee on 1 st April, 1972.Some new points revised and two new subjects organized are mainly as follows:1. JIS M8801-1972 (Coal)1) Size analysis testTwo millimeter size analysis was adopted newly to present method for coal of power station use.2) Crucible swelling testIt was adopted to determine the crucible swelling number from the calibration curve between areas of the standard profiles and swelling numbers, when the shape of residue (button) is irregular or the swelling number exceeds nine. The electrical heating method (same to ISO R 501) was added newly to present gas heating method.3) Plasticity testGieseler plastometer method (nearly equal to ASTM D 1812-66, D 2639-67 T) was newly organized as one of the new subjects.4) Fusibility test of coal ashUse of large cone size (same to ASTM D 1857-64 T) was recognized for convenience of observation.5) Grindability testHardgrove method (nearly equal to ASTM D 409-51) was newly organized as one of the new subjects by the wish of power station side.2. JIS K 2151-1972 (Coke)1) Apparent density testVolume method was added newly to present weight method (nearly equal to ASTM D167).2) Drum strength testTwo methods of drum test and tumbler test (same to ASTM D 294) have been contained in this term. Two new subjects of 150 r. p.m. method and uniform-size coke method were newly appointed in the drum test.3) Reactivity testIt was recognized to use the analytical apparatus such as gas chromatograph and infrared spectrometer for CO gas analyser.

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The first measurement of nocturnal activity by recording apparatus was by Johnson ('26). Relatively heavy animals were used, e.g., forest deer mice, which allowed a simple technique to be employed. This consisted in placing a mouse in a light-weight cage suspended by rubber bands. An indicator fastened to the cage traced the animal's movements on a record made by a paper disk turned by clock mechanism. Unfortunately the apparatus, though simple, was neither figured nor fully explained; neither was the temperature, which varied seven degrees, nor presumably the humidity, adequately controlled. The work was important, however, in that it recorded nocturnal activity, and gave an insight into the behavior of characteristic forest rodents. Quite recently Davis ('32, '33) has reported an improved apparatus of the same general type for recording the activity of small mammals. Turning from mammals to the insects, the only other group of animals in which nocturnal activity has been measured by recording apparatus, significant work has been done by Lutz ('32a, b) on three species of Orthoptera. Here the small weight of the animals necessitated a much more refined technique. This work is so recent that it is sufficient to mention the lprinciple used. The weight of an insect depressed a counter-balanced treadle, completing an electric circuit through an electromagnet, which in turn moved an inked pen which registered the animal's movements upon a moving drum. Unhappily such an excellent piece of equipment was neither described nor figured in the text, nor were the experimental conditions of the cellar, in which the experiments were conducted, fully described. The work, however, is the best that has been done with recording apparatus in measuring nocturnal activity. Four years ago the writer began construction of a recording apparatus' which would measure objectively the activity of small animals. The circular disk of a phonograph, having a diameter of eleven and three-quarter inches, or No. 10 aluminum pan-covers, were threaded at the exact center so that a brass screw, which was lathed to a blunt point, could be inserted from above and adjusted to any required length. This screw point was centered on a dish-shaped table made by cutting off the end of another brass screwv and