The aim of this study was to compare the effects of two types of study assignment on the achievements of high school students on three types of biology examination. One examination consisted of objective questions, a second of subjective questions of the short essay type, while the third was a combination of objective and subjective questions. One type of assignment consisted of questions of the objective type, the other of questions of the short essay type. Of related interest were the possible effects of a high percentage of objective examination questions, on the use by teachers of essay assignments. An experiment of the matched parallel groups type was carried out. The experimental variable was the type of study assignment given, consisting of either objective or short essay questions. The duration of the experiment was six weeks, the academic subject field was biology, the groups received similar teaching, and comparisons were made on the results of specially constructed tests administered before and after the teaching period. Each test consisted of an objective examination and an essay examination. The mean gains of the two groups on each type of examination were compared. Results on what could be considered a mixed examination were obtained by combining the results of the objective and essay examinations. The objective and essay parts were weighted in such a way that the mixed examination could be considered to resemble the type of examination in biology set by the British Columbia Department of Education. A final comparison was made between students’ results on the experimental tests and on the actual departmental examination. Attempts were made to establish the validity and reliability of the objective test but it was not possible to establish any particular degree of validity or reliability for the essay test. After statistical treatment, it was found that there was no significant difference at the five percent level between the results of the groups on any of the three experimental tests. Some difficulty was experienced in comparing the results of the experimental tests with those of the departmental examination. This was due to the system of recommendation which does not require the top-sixty percent to write the departmental examination, making it impossible to obtain a representative sample for comparison in this study. Certain conclusions were drawn subject to the limitations of the tests and of the general, experimental conditions. Comparing the use of objective and essay study assignments: (1) there seemed to be no difference in the effect on the results on an objective test. Teachers and their students might feel free to use either type of study assignment in biology, (2) nothing in the study indicated any difference in the effect on an essay test, (3) nothing in the study indicated any difference in the effect on a combined objective-essay test of the type used by the Department of Education, nothing in the study indicated that the use of one type of study assignment rather than the other would hamper a student's chances of success on a biology examination of the type set by the Department of Education. In summary it may be said that the type of examination in biology set by the British Columbia Department of Education did not appear to place any restriction on the type of study assignment used in high schools, provided that the assignments were comprehensive in their cover of the material under study. / Education, Faculty of / Graduate

Photogrammetry has become increasingly important in the practice of forestry. Recently, the trend has been toward the development of photo-mensurational techniques for direct estimation of timber resources. The purpose of the present study was to assess the possibility of applying aerial stand-volume multiple-regression equations for the application of photo-mensurational techniques on several kinds of air photos. Field data were collected from sample plots located in the U.B.C. Research Forest at Haney as well as from the forest on the campus of the University of British Columbia, in Vancouver. Modifications in technique for the determination of tree height, crown width and crown closure were developed by the writer and are described in this study. Multiple linear-regression equations were used for the analysis of data. Application of the Electronic Computer Alwac III-E to solve all the multiple linear-regression equations is described briefly. Ease of typing was evaluated subjectively. The present study has indicated: (1) Using a spherical densiometer, a ground estimate of crown closure in per cent resulted in an over-estimate, as compared with the photo-estimate. (2) Tree count could not be used effectively as an independent variable in the construction of the photo-volume equation. (3) Best results were secured when photographs: were taken with a 12-inch focal length and a flying height of 15,600 feet above sea level. (4) For the construction of photo-volume tables, height, crown width and crown closure should be used as independent variables, especially when more than one interpreter is involved. (5) No significant differences were found among photographic papers or finishes used for the determination of photo volume. (6) Photography with a Representative Fraction (RF) of 1:15,840 should be satisfactory for forest typing. (7) The greatest variation was among photo-interpreters. (8) Photo-interpretation could be improved by the standardization of photo-interpretation procedures. / Forestry, Faculty of / Graduate

Even-aged well stocked aspen stands in Northern Alberta were sampled in order to derive "normal" yields per acre for number and size of trees, basal area, and various measures of volume. The stands occur chiefly on three qualities of site which have been classified into Pair, Medium and Good by the average height of dominant trees at 80 years. Exceptionally high mortality per decade is characteristic in fully stocked young aspen stands and the relation of number of trees per acre to average diameter is markedly different from the trends found by investigators for other species., A table of stand density units was constructed to permit the, rapid calculation of stand-density index when average diameter and number of trees per acre have been determined. The mean annual cubic volume growth on medium sites is maximum at age 40. For merchantable cubic and board feet, growth reaches a peak at 85 and 130 years respectively. Data from two other regions show that the amount of cull is high in aspen trees above 80 years of age, this indicates that the wood should be utilized before a stand-age of 130 years is reached if maximum return in board foot volume is desired. By 140 years aspen stands show signs of breaking up. The hardwood stands measured were composed mainly of aspen but both white birch and black poplar occurred on many of the plots. The growth of the black poplar is only slightly less than that for the aspen. It has consistently lower volumes per tree which permits the use of aspen volume tables when correction factors are applied. / Forestry, Faculty of / Graduate

The Full-Displacement Pressuremeter (FDPM) Test is one in which a pressuremeter is installed in the soil by pushing it behind a conical tip. Earlier work had indicated that the unload-reload modulus measured with the FDPM was very similar to that obtained from self-boring pressuremeter (SBPM) testing. It had also been suggested that if the pressuremeter was capable of sufficient expansion, the interpreted soil properties would be those of the soil beyond the zone of disturbance. This study examined the factors affecting the measurement, analysis and interpretation of soil properties from FDPM pressure-expansion curves in sands with emphasis on the unload-reload modulus. The effects of equipment design and dimensions, installation method and of test procedure on the analysis and interpretation of lateral stress, shear strength and stiffness were studied during laboratory and field evaluation of two prototype FDPMs. The overwhelming importance of instrument dimensions and tolerances on the test results was clearly shown. Movements of a fraction of a millimetre can have a large effect on the measured lateral stress and stiffness. Test procedures were also shown to have a large effect on the data obtained. It was demonstrated that rate effects became important in pressuremeter tests involving expansion to large strains and a stress-strain strain rate concept was proposed to aid in the understanding of these effects. Theories developed for the interpretation of shear strength of sands from SBPM tests were shown to be inapplicable to the interpretation of FDPM test results. The unload-reload modulus was shown to be an indicator of soil stiffness but the effects of stress level and degree of unloading have to be considered when attempting to derive a stiffness for design. A rational approach to the interpretation of modulus was presented and it was shown that unload-reload moduli from both SBPM and FDPM could be interpreted using the same approach. The need for standardising the equipment design, testing procedures and methods of analysis and interpretation was shown. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Time-average and stroboscopic real-time holography have become established as the prominent tools of holographic vibration analysis. Both are able to provide a quantitative determination of the amplitudes of standing waves of a vibrating flat surface, but have to date been limited to qualitative examination of curved surfaces. The purpose of this thesis has been to investigate the problems of extending the holographic technique to the analysis of surfaces of single curvature. The presence of several component motions in curved surface vibration prompted an examination of the fringe behaviour of the individual components of motion. This was performed by studying pure rigid body step displacements using double exposure holography. The experimental work of previous investigators was duplicated and the results tabulated according to the sensitivities of the fringe period density to a change in displacement magnitude. This was then related to the rotations and translations occurring in the motion of a vibrating surface. A fully clamped curved panel was studied using the time-average method with the assumption that all points on the surface were displaced normal to it. Good agreement was obtained between the amplitudes calculated from the fringes and the measured amplitudes, by accounting for the variation in displacement direction across the surface. A fixed-free cylinder was examined simultaneously from two overlapping views using both the time-average and stroboscopic real-time methods. Comparison of the calculated and measured amplitudes of the time-average indicated that the interference fringes were not localized upon or very near the cylinder's surface. The real-time results had reinforced these findings. However, the inherent presence of residual fringes in this method caused difficulties in obtaining an accurate quantitative evaluation of the vibration amplitudes. The real-time fringes were analyzed with attention paid to the effects of the initial residual fringes upon the resultant fringes. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

This thesis is concerned with tolerances for magnetic field imperfections in the TRIUMF cyclotron set by the betatron oscillation resonances v[formula omitted] = 1.0, v[formula omitted] – v[formula omitted] = 1.0 and v[formula omitted] = 1.5. These resonances, encountered during acceleration, can lead to undesirable growth in the amplitudes of the betatron oscillations. We first derive equations of motion that take into account non-linear terms and field imperfections, and show how resonance conditions may occur. These conditions were simulated in our orbit codes and numerical calculations were made to determine the tolerances they impose on the magnetic field. We have made a detailed investigation of the effect on the behaviour of the beam of first harmonic bumps at radii less than 150 in. The first harmonic tolerance of 0.1 G to produce an increase in the radial amplitude of 0.1 in. is in agreement with analytical calculations. We have also shown that this tolerance, too small to be seen in the magnetic field survey, may be achieved by suitable adjustments in the harmonic coil settings. Tolerances on the second harmonic imperfection are also presented. To determine the tolerances set by the coupled resonance v[formula omitted] – v[formula omitted] = 1.0, we have simulated a first harmonic twist in the median plane. The results show that, for high current poor resolution experiments, the magnitude of the twist on entering the resonance is of no importance, provided the amplitudes of the radial and vertical betatron oscillations are not much larger than the estimate of 0.2 in. For high resolution experiments, the tolerances on the slope of the twist are of the order of a few mrad. Analytical estimates of these tolerances are also presented. Finally, we have determined that the v[formula omitted] = 1.5 resonance sets an upper limit to the gradient of the third harmonic of about 0.2 G/in., which produces a 20% increase in the radial betatron amplitude. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In the past, spectral analysis of Arctic Sea ambient noise has been carried out by octave band pass filtering and linear rectification, followed by analogue Integration. To relate this integral to the power spectral density of the noise, the amplitude distribution of the noise has been assumed to be Gaussian, giving rise to certain errors. A system is proposed which consists of a stage of variable gain followed by a polarity coincidence statistical wattmeter and measures the power spectral density of ambient noise after band pass filtering. The wattmeter will handle an input signal dynamic range of at least 20 dB and does so regardless of the statistical nature of the noise. This dynamic range is extended dynamically by controlling the gain of the driving stage. The gain level is automatically adjusted during a one minute "adaptive" time interval so that the noise delivered to the wattmeter is over the region of optimal system operation. Measurement of the power spectral density of the ambient noise is then made in the subsequent four minute interval. A prototype wattmeter has been constructed and tested. The gain level is determined by requiring that the noise not exceed fixed levels more than a certain percentage of the time. This automatic adjustment is carried out during a one minute adaptive time interval, and a relatively accurate measure of the mean square value of the noise is determined during the four minutes that follow. For purposes of testing the prototype, d.c. inputs and sinusoidal inputs of wide frequency and amplitude ranges were used. The actual root mean square value of the inputs was measured with a thermal milliammeter and a precision voltage divider. The results of these tests show the region of operation where the input-output relationship of the wattmeter is linear. From these results, suggestions are made.as to how the proposed system could be modified to replace the analogue system used for Arctic Sea ambient noise spectral analysis. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

A great many kinds and forms of volume equations can be found in any review of the literature on this topic. At least four procedures are available for comparing volume equations to judge which one gives the best estimate of volume. These procedures are evaluated in this thesis for seven volume equation forms: [equation forms omitted] and two new methods are introduced: (l) Taylor's series for estimating errors and (2) sum of absolute deviations. Comparisons of above equations with different procedures were carried out for two species, lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss.). Merchantable volumes of both species were described by three subsets of data which were grouped according to the following Girard form quotients for 32 foot logs: 1. 80+ 2. 70-79 3. <69. It was found that none of the presently available procedures, including the two new ones, can by itself indicate the best tree volume equation, which led to the conclusion that whenever more than a quick approximation is required, at least two of the methods should be used simultaneously. Both relative and absolute measures of residual variation must be considered. It is concluded that choice of equation form depends very much on the specific requirements of the research or operational project involved. / Forestry, Faculty of / Graduate

The use of optical techniques for the study of vibrating surfaces has thus far been limited to measuring small amplitudes on the order of a few hundred microinches. To extend the measuring range to much larger amplitudes a completely new technique is sought. In this thesis optical vibration methods are presented that allow amplitudes of .001" and up to be investigated, the upper limit being determined solely by the prohibitive size and cost of the equipment. The study is based on a combination of the shadow moire deflection measuring method and the Salet-Ikeda slope measuring method which, as far as the author knows, have been applied only to the study of static situations. It is shown how these two methods may be applied to the dynamic case to permit the direct visualization of nodal and antinodal locations and displacements in vibrating plates. Three specimens are studied: a cantilever beam, a square cantilever plate and a circular free plate. Complete photographic results along with theoretical or experimental solutions are given for each specimen. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Variations in western hemlock tree and stand growth were analysed to determine the relative importance of causative factors. Four phases in a stand's life-cycle were investigated (seedling establishment, juvenile growth, early stand formation, and middle-age). Detailed analyses of tree growth were made at the time of early stand formation (25 to 35 years). Stand growth and yield data (15 to 160 years) were analysed by multiple regression methods to ascertain the effects of varying density regimes on time and magnitude of maximum wood volume per acre. In all stands studied, tree height was unaffected by variations in stand density. Detailed analyses of current breast-height radial growth indicated that the factors of antecedent growth, tree d.b.h., stand density, age, and site quality were of decreasing importance in the order listed. Statistically, the best measures of stand density were ratios of crown width and live crown length with total tree height, although stand basal area per acre was only slightly less significant. Stand fertilisation with nitrogen stimulated tree radial growth and changed the relative concentrations of foliar nutrients within the crown. Limited (15 trees) biomass studies indicated that production per unit area of above-ground tree weight (oven-dry) increased linearly with greater stand density. Yield increased directly in proportion to the fraction of area occupied by trees (stocking) and curvilinearly with degree of crowding (stand density) within the area occupied. Mean annual net volume increment did not culminate even at stand densities of 500 square feet of basal area per acre. Both intensive and extensive forest management was discussed. Within the Coastal hemlock zone there could be many advantages for a shelterwood regeneration system and two-storey high forest with western hemlock as a supplementary species. / Forestry, Faculty of / Graduate