Graphical Aids Research Articles

A graphical aid for calculating structure factors

A graphical aid for calculating structure factors

Permissible Voids in Photon Shields

Permissible void volume in photon shields is calculated in terms of shield thickness, photon energy, and permissible leakage factor. Several graphical aids for lead are presented. A simple method o...

Graphic Aids for Teaching Coriolis Force

Graphical “paper experiments” are described which facilitate the study of Coriolis force and other forces which arise from the use of accelerated axes of reference. The development emphasizes the operational definition that an inertial frame of reference is a coordinate system in which a free body moves at constant velocity in a straight line. It is pointed out that the tangential component of Coriolis force is just that force needed to produce the torque which conserves angular momentum.

Another graphical aid for the evaluation of absorption corrections by Albrecht's method

Another graphical aid for the evaluation of absorption corrections by Albrecht's method

Straight-Field Permanent Magnets of Minimum Weight for TWT Focusing-Design and Graphic Aids in Design

A convenient design formula has been derived which enables one to estimate readily the minimum amount of magnetic material which will satisfy a given set of field strength requirements on the axis of a tubular permanent magnet. Such a magnet is suitable for focusing the beam of a traveling-wave tube (twt) with coaxial rf fittings if small holes are provided in the side of the magnet to admit the coaxial lines. The calculation is further expedited by the use of design graphs, based upon the formula, from which one can read off directly the required cross section area at the middle of the magnet. From this value one may calculate the average cross section, volume, and weight of magnetic material. A correction factor has been derived which also enables one to apply the results for the simple tubular magnet directly to the case of magnets specially shaped to fit around waveguide. The validity of the formula and of the associated design graphs has been confirmed by tests upon a series of magnets. These magnets covered a considerable range of field requirements and of size, varying in weight from three to twenty pounds.

Procedures for Estimating Noise Exposure and Resulting Community Reaction from Air Base Operations

An air base may be considered as a complex noise source. Its noise characteristics are determined primarily by the nature of the take-off and ground runup operations of jet aircraft. The time pattern of noise produced by these operations depends on many factors including the type of aircraft involved, their flight profiles and flight paths, the time schedule of operations, runway utilization, the location and orientation of aircraft during runups, and the power settings of the aircraft. Based on a number of measurements of noise produced by jet aircraft operating on the ground and in flight, engineering procedures have been developed for computing the noise exposure that would exist in communities near air bases. Graphical aids in the form of noise contour overlays are utilized in the computation of the noise exposure. These procedures are described in some detail, and tentative relations between community response and noise exposure are discussed. An illustrative example is given in which noise contours are constructed around a hypothetical air base for a given set of operating conditions. (Supported in part by U. S. Air Force.)

A graphical aid for the rapid evaluation of absorption corrections by Albrecht's method

A graphical aid for the rapid evaluation of absorption corrections by Albrecht's method

Graphic Aids in Study of Strata

ABSTRACT Experiments with several vocabularic and graphic techniques involving pre-field organization have led to a final hinged-card field log which is plotted directly in the field as measurement, collection, and field description of the stratigraphic section proceed. This graphic field log can be at any scale consistent with good sedimentologic sampling, but should contain spaces for the entry of all subsequent laboratory data. Upon completion of field and laboratory work, this dual log may be used for direct plotting on tracing cloth, or may be reduced by photostat for the construction of cross sections.

Graphic aids for calculating rectifier locomotive performance

THE SUCCESS of any product is often determined by its ability to give customer satisfaction when operated under a wide range of conditions. All too often, these conditions differ appreciably from the specification upon which performance guarantees are based. To assure product satisfaction, the ability to project correctly the knowledge of product behavior from known to unknown regions is essential.

Frequency response from experimental nonoscillatory transient-response data

Curves are derived and presented which provide a ready means for approximating transfer functions with time constants up to three in number, and also dead time, from the experimental non-oscillatory transient response produced by a step change. The transfer function containing the time constants and dead time may be used to obtain the corresponding frequency response. These curves then are a graphical aid for converting transient response into frequency response.

Experimental Flight Methods for Evaluating Frequency-Response Characteristics of Aircraft

Abstract This paper deals mainly with methods and techniques for obtaining airplane frequency-response characteristics from transient flight measurements. After a review of the basic airplane equations of motion, the theoretical transfer function which defines the “short-period” pitch response to an elevator deflection is derived. A numerical example is used to illustrate the evaluation of an analytical transfer function from a graphical frequency response by a method which involves the use of graphical aids in conjunction with an analog computer. Finally, the effects of variations in flight speed and altitude on the airplane response are considered.

Graphical Aids in Interpreting the Performance of Crystal Transducers

When the mechanical damping of a transducer is large, as by acoustic radiation from one or both faces into a liquid or solid, the circular diagram that represents its characteristics requires special treatment. As a background for this treatment, the uses and limitations of the conventional circle for a resonator with small losses is first reviewed. The problem of the transducer with large losses is then considered with special reference to the equations and graphs for a thickness-type transducer with unsymmetrical loading. For plane-wave transducers the expressions are exact for all loads and at all frequencies, including harmonics. Either the voltage or the current may be constant. From the admittance or impedance diagrams the magnitude and phase of current, voltage, particle velocity, and vibrational amplitude at any frequency can be obtained immediately. Similar results would be found with plates in lengthwise vibration. A new type of diagram is developed for representing vibrational amplitudes. As an illustration, the case of a quartz plate radiating into three liquids of widely different acoustic properties is treated. When the load is unsymmetrical, there is no true node anywhere in the crystal except when the load is zero or infinity. There is, however, a plane of minimal vibration, the amplitude and location of which are derived. The equations indicate certain peculiar effects when the specific acoustic resistance of the medium is just twice that of the crystal.

The Beta Function

The First Eulerian Integral, called the Beta Function, is defined by B(x, y) =folt-1(1 -t)Y-ldt, which converges for x > 0 and y > 0. The well-known equation connecting the Beta and Gamma functions, B(x, y) = r(x)r(y)/r(x+y), is therefore valid only for positive real x and y. However, this relation is commonly used as a definition, to extend B(x, y) so that the function has meaning for values other than positive real x, y. It is the purpose of this paper to discuss the behavior of B(x, y) over all real x and y for which the function is thus defined. The discussion is greatly facilitated by graphic aids. Since B(x, y) is continuous (with isolated exceptions) over the regions of definition, it can be represented by a Cartesian surface, z=B(x, y). In particular, z is continuous for all x>0, y>0, and so is represented by a smooth unbroken surface throughout the first octant (Fig. 1). Since it is obvious from the extended definition that B(x, y)

On the Errors of Biological Assays with Graded Responses, and Their Graphical Derivation

CALCULATION of the fiducial limits of error of a bioassay is intricate. A technical assistant, computing by rote, is unlikely to be able to decide whether an abnormal result is due to miscalculation or is inherent in the data. Nomography and the use of error curves can reduce his labors, promote his confidence, and advance his insight into the factors contributing to the assay error. Several graphical aids for bioassays and errors are already available, e.g. those of de Beer [1], Knudsen & Randall [2], Bliss [3], Sherwood [4], Goyan & Dufrenoy [5], Koch [6], and Harte [7]. Lees's specific calculating machine [8] should also be mentioned in this connexion. The most recent aid, and perhaps the one most nearly suited to the requirements of the writer's laboratory, is that of Healy [9], whose nomogram gives errors for assays of given size and structure. The present requirements, however, were error charts covering 4and 6point assays of given design but greatly varying size. It was not required to calculate graphically the mean estimate itself, the writer being unable to appreciate the advantages of so replacing the simple arithmetic operations involved. The devisal of appropriate error charts, the main subject of this paper, has thrown into relief some aspects of assay design and error factors that may be worthy of concomitant record.

Graphical, Mechanical, and Electrical Aids for Compressible Fluid Flow

Abstract Graphical, mechanical, and electrical methods of studying two-dimensional and axially symmetrical irrotational flow of nonviscous compressible fluids are described and examples are given of problems solved by these methods. Rules for the construction of compressible flux plots using wires, beads, and a suitable device for obtaining the desired length-width ratios of the rectangles are derived, and the apparatus used is described. An analogy is described by means of which these problems can be solved by the use of a d-c resistance board, employing variable resistances which are adjusted to conform to the derived relations. Designers and aerodynamicists in need of solution for problems for which no analytical solutions are available can use the methods described in this paper to obtain the required solutions.

A Graphical Aid to the Selection of Best-Time Tracks

It the “mean effective on-track wind components” along the Great Circle track and any other track of known length are known, it is possible to compare flight-times along the two tracks. A graph is devised whereby it may be determined whether or not the longer track offers a shorter flight-time. By comparing several likely-looking tracks, that one which most closely, approximates the best-time track may be found.

Some Notes on the Measurement of Acoustic Impedance

A modified form of an earlier design of impedance tube is described here. It is capable of measuring the normal impedance of a sample by the variable length, variable frequency, or traveling microphone methods without disturbing the sample in transferring from one test method to another. The tube also may be used to measure the transmission constant with the aid of a long probe tube. Modern graphical aids to the calculation of the impedance from the quantities measured in the tube are described. Comparison of data obtained by the variable length and traveling microphone methods is made, and good agreement is found over most of the frequency range. It is shown that the clamping effects of the tube walls on the edge of a lightweight, non-rigid sample are serious enough to introduce large gyrations of the impedance curves at frequencies below 500 c.p.s.

Graphical and tabular aids for determining sample size when planning experiments which involve comparisons of percentages

When one knows in advance the minimum percentage difference which will be of practical interest in an investigation, principles of economy suggest the desirability of an accurate estimate of the size of the sample to be used. Charts are presented which eliminate any computation where the two groups involved are to be equal. A table is included for the case where one group will be from one to three times the size of the other. The charts are also useful for determining whether or not obtained differences are statistically significant at the 5 per cent or the 1 per cent level.

Graphic Aids in Myology

Journal Article Graphic Aids in Myology Get access Graphic Aids in Myology. By Raymond H. Houser. Paper. Price, $1. Pp. 20. Physical Therapy, Volume 25, Issue 5, September 1945, Page 258, https://doi.org/10.1093/ptj/25.5.258b Published: 01 September 1945

Graphic Aids in Neurology

Journal Article Graphic Aids in Neurology Get access Graphic Aids in Neurolosry. By Raymond H. Houser. Paper. Price, $1 Pp. 20. San Diego, Calif.: Scientific Illustrators, 1945. Physical Therapy, Volume 25, Issue 5, September 1945, Page 258, https://doi.org/10.1093/ptj/25.5.258c Published: 01 September 1945