Measurement Of Such Parameters Research Articles

Measurement of geometric parameters in plastic surgery research: use of the departmental microcomputer

Three types of digitising device are described which may be used with a microcomputer for the measurement of such parameters as length, distance, area, angles and point counts. Some applications in plastic surgery research are considered.

Eye Deformation Measurement by Laser Interferometry

Using low-power laser illumination of the human eye in vivo, it is possible to observe interference fringes produced by light reflected from different optical interfaces within the eye, in particular from the front surface of the cornea and from the retina. Real-time changes in these fringes have also been observed, reflecting deformation of the eye in response to the subject's heart-beat. Some experimental results are presented. Possible applications of this technique include its use as an ophthalmological diagnostic tool in the measurement of such parameters as eye rigidity and intra-ocular pressure.

Use of the full polarization measurement in the partial reflection experiment

Application of the theory of a partially polarized wave is made to the D-region partial reflection experiment. A relatively simple experiment is described which allows measurement of such parameters as differential absorption, differential phase, and the amount of polarized power in the received signal. The results of this measurement are used to estimate the structure of the scattering irregularities and to indicate the presence of oblique contamination.

An Advanced Apparatus for the Study of Roller and Cage Slip in High-Speed Roller Bearings

This paper describes a sophisticated research facility for the study of roller bearings at DN values of over one million with provisions for the measurement of such parameters as cage and roller speeds, bearing torque and load, and bearing ring temperatures. Particular features of the apparatus are a laser Doppler anemometer (LDA) system, with the ability to measure an instantaneous roller speed at any position in the bearing, an infrared radiation thermometer for measuring the bearing inner ring temperature, hydrostatic mounting of the test spindle, and aerostatic bearings which insure a good axial location of the test bearing and form important elements of torque and load measuring facilities which are, at once, integral and independent.

A Model for Oceanic Crystal Structure Developed

The plastic upward flow of asthenosphere at mid-ocean ridge crests implies a linear basaltic magma chamber at the base of the ocean crust at ridge crests. This in turn implies a mature oceanic crust composed of a unit of lavas and dykes, overlying a unit of isotropic gabbro, formed by upward cooling of the magma chamber, overlying a unit of cumulate gabbros and ultramafics, overlying residual mantle from which the basaltic magma has been removed. Analysis of this structure shows that it is asymmetric, with lavas and cumulates dipping towards the spreading centre, and dykes predominantly chilled away from the spreading centre. Increase in spreading rate leads to an increase in lava dips, to a separation of lavas and dykes into distinct units, to a thinning of the dyke unit, and to a narrowing of individual dykes. Metamorphic facies and seismic layering may, but do not necessarily, correspond with this lithological layering. The degree of rifting of oceanic crust and the depth of the median valley are related to an interplay of spreading rate and viscosity of the rising asthenospheric material. Measurement of such parameters as direction and extent of one-way chilling of dykes, dyke thickness, lava dip, and degree of separation of lavas and dykes, in sequence-type ophiolite complexes should allow the determination of direction and rate of spreading at the mid-ocean ridges at which they were formed. The model implies cogenetic liquid-solid relationships between ocean-floor rocks, and suggests changes in the shape of the liquid-solid phase diagram over the pressure range 0.5–2 kb, as well as extensive development of ocean-floor metamorphic rocks.

Effects of dietary and iron supplementation on hematocrit levels of preschool children

The effects of a 5 week period of dietary and medicinal iron supplementation on hematocrit levels of a group of preschool children from low socioeconomic backgrounds were studied. Two thirds of all children showed no change in hematocrit levels. Diet alone and diet plus 30 mg. of elemental iron per day were associated with statistically significant increases in mean hematocrit level. A slightly greater increase in mean hematocrit was seen in the iron-supplemented group. This study indicates that although severe nutritional anemia is not a common problem in this group of children, short-term improvement in nutrition is followed by significant increases in hematocrit. Only slight additive effect was obtained by the use of medicinal iron in the diet. It is suggested that an increase in hematocrit or hemoglobin level following therapy may constitute a better indicator of the prevalence of nutritional deficiency than a single measurement of such parameters as hemoglobin, hematocrit, or serum iron.

Prediction and Evaluation of Active Sonar-System Detection Preformance

The concept of signal excess—that is, the excess of signal received over that required for detection—as commonly used in both prediction and evaluation of active sonar-system detection performance is presented. Some of the results of independent measurements of the nominal value and the variability of the various parameters in the signal excess equation are discussed in terms of the deviation of a prediction from the actual evaluation of over-all system performance. Examples are used to demonstrate that the predicted performance will equal the over-all performance as measured for a total system only after recognition and adjustment for parameter interrelationships are made. Acoustic models that have been developed, validated in system tests, and used for active sonar-system performance prediction are shown. Criteria that have been imposed in the measurement of such parameters as source level, receiving sensitivity, propagation loss, interferring noise, and others, are presented together with illustrations of the effectiveness when used. Uncertainties in predicted system performance resulting from parameters and measurements that cannot be controlled or accurately estimated are cited and discussed.

A New Approach to Horizontal Deflection Tube Testing

Static methods of testing horizontal deflection tubes have become inadequate and are being replaced by more significant methods of dynamic testing. This paper presents the problems encountered in arriving at a suitable dynamic test. It suggests a desirable test method to drive the horizontal deflection tube with a square-wave signal, thus permitting the measurement of such parameters as peak currents, Ib-to-Ic2 ratio, and the voltage at the knee of the plate characteristic.