Showing papers by "Applied Science Private University published in 1970"

Deformation of Particles during Briquetting

Abstract: THE briquetting of small particles usually consists of the application of pressure in controlled conditions so that the individual particles hold together to form a coherent compact. Many mechanisms have been suggested to explain why the particles cohere to form a compact, but none have been based on satisfactory observation of the behaviour of the individual particles under stress. Our present studies have involved such detailed observation and we describe here the essential difference in behaviour of particles of a number of different materials.

Cardiac output from transthoracic impedance variations

Abstract: Many attempts have been made to estimate cardiac output (CO) in man from transthoracic electrical impedance fluctuations. Generally, data for comparable CO values obtained from impedance records (ZR) and from indicator dilutions curves ( IDC) have not shown satisfactory agreement. We have demonstrated, using a particular impedance plethysmograph, that a good empirical correlation of these data exists if characteristics of the subject and the waveform of the ZR are first used to provide subject groups. Our experience is based on records obtained from 87 heart patients. The evidence suggests that this is a statistically significant number and that individual values of CO predicted from ZR can be expected to have an accuracy comparable to that computed from IDC. As a consequence, it is hypothesized that the determination of absolute values of CO from transthoracic ZR is dependent upon characteristics of the subjects and the ZR waveform. This paper is ;i summary of methods and results that support these statements and the hypothesis.

Nonsteady Flow to Surface Reservoir

Abstract: When ground water flows from an unconfined aquifer to a surface reservoir the position of the water table will change with time. The nonlinear partial differential equation for water table elevation is transformed to a nonlinear ordinary differential equation by similarity substitution and a numerical procedure for its solution is presented. A method of computing bank storage is presented. The solution compares favorably with the experimental results obtained by others.

Application of the bilinear Z-transform method to ground motion studies

Abstract: A recursive relationship in the time domain is derived for the response of a single degree of freedom oscillator to an arbitrary digitized ground motion. In developing the relationship the oscillator9s continuous frequency response characteristics are expressed in terms of an equivalent sampled function Z -plane representation using the bilinear Z -transform method. Oscillator response time histories and response spectra for prescribed ground motions are compared with exact solutions. Application of the presented method to instrument correction studies is discussed.