On single-amplifier immittance inverters and their use in active filter design

Imperial Users onl

Development of flat-plate solar collectors for the heating and cooling of buildings

The relevant design parameters in the fabrication of a solar collector for heating liquids were examined. The objective was to design, fabricate, and test a low-cost, flat-plate solar collector with high collection efficiency, high durability, and requiring little maintenance. Computer-aided math models of the heat transfer processes in the collector assisted in the design. The preferred physical design parameters were determined from a heat transfer standpoint and the absorber panel configuration, the surface treatment of the absorber panel, the type and thickness of insulation, and the number, spacing and material of the covers were defined. Variations of this configuration were identified, prototypes built, and performance tests performed using a solar simulator. Simulated operation of the baseline collector configuration was combined with insolation data for a number of locations and compared with a predicted load to determine the degree of solar utilization

A general method for calculating three-dimensional compressible laminar and turbulent boundary layers on arbitrary wings

The method described utilizes a nonorthogonal coordinate system for boundary-layer calculations. It includes a geometry program that represents the wing analytically, and a velocity program that computes the external velocity components from a given experimental pressure distribution when the external velocity distribution is not computed theoretically. The boundary layer method is general, however, and can also be used for an external velocity distribution computed theoretically. Several test cases were computed by this method and the results were checked with other numerical calculations and with experiments when available. A typical computation time (CPU) on an IBM 370/165 computer for one surface of a wing which roughly consist of 30 spanwise stations and 25 streamwise stations, with 30 points across the boundary layer is less than 30 seconds for an incompressible flow and a little more for a compressible flow

A Computer Program for Calculating Three-Dimensional Compressible Laminar and Turbulent Boundary Layers on Arbitrary Wings

A computer program for calculating three dimensional compressible laminar and turbulent boundary layers on arbitrary wings is described and presented. The computer program consists of three separate programs, namely, a geometry program to represent the wing analytically, a velocity program to compute the external velocity components from a given experimental pressure distribution and a finite difference boundary layer method to solve the governing equations for compressible flows. To illustrate the usage of the computer program, three different test cases are presented and the preparation of the input data as well as the computed output data is discussed in some detail

Calculation of three-dimensional compressible laminar and turbulent boundary layers. Calculation of three-dimensional compressible boundary layers on arbitrary wings

A very general method for calculating compressible three-dimensional laminar and turbulent boundary layers on arbitrary wings is described. The method utilizes a nonorthogonal coordinate system for the boundary-layer calculations and includes a geometry package that represents the wing analytically. In the calculations all the geometric parameters of the coordinate system are accounted for. The Reynolds shear-stress terms are modeled by an eddy-viscosity formulation developed by Cebeci. The governing equations are solved by a very efficient two-point finite-difference method used earlier by Keller and Cebeci for two-dimensional flows and later by Cebeci for three-dimensional flows

Application of Radio Techniques In The Classroom In The Secondary Schools

It is the purpose of this thesis to give the types and sources of radio educational programs and to point out the methods and techniques of adapting these programs to the classroom situation, and also to show the equipment necessary in this application and how this equipment may be used. It is also the purpose of this research not only to show how radio sources have been used in the classroom, but also to point out other desirable uses. The Application of Radio Techniques in the Classrooms in the Secondary Schools brings into focus the impact of radio upon education will: (1) attempt to present in an organized manner the varying aspects of radio in education and, to show the relation of these aspects of radio to the classroom USB; (2) show the practicability of radio in education; (3) show the problems in education that may be solved through the application of radio; and (4) will demonstrate the promising future that radio has in the field of education

Aquiculture

There is every evidence that the productivity of our ponds, lakes, and streams can be materially increased by the intelligent application of present scientific knowledge to this problem. For many years it has been recognized that our streams and lakes are becoming more and more barren of fish, and other aquatic life, but remedial measures, until recently, have been applied to only one-half of the problem. Efficient fish hatchery systems are maintained, both state and federal, and millions of fingerlings and legal-size fish are planted each year in an effort to increase the fish population of our waters, and to add to the profit and enjoyment of an increasing army of fishermen. On the other hand, little thought has been given to the fate of these fish after they have been released, and to the ability of our streams and lakes to provide the essentials of life for an increased fish population. Concurrent with the pushing back of our frontiers has been the wanton destruction of timber, the reduction of underground water tables, increased erosion and silt, increased temperature and pollution of streams, and quick run-off of surface water with consequent floods, a decrease in the volume of water in creeks and rivers during the dry seasons, as well as many other factors which have a direct bearing upon the productivity of streams and lakes. With the advent of the automobile, followed by the extension of our highway system to virtually every nook and corner, there are now few streams of any size that are not accessibly to the ardent fisherman. As distance from a stream is now a negligible factor, the number of fishermen is growing each year and the sportsmen feel that they are entitled to some return for the money invested in the purchase of a privilege license. The answer to this problem apparently lies in the extension of the principles of aquiculture, heretofore more or less restricted to the hatcheries, to include our public waters

Big Men On Campus: Administrative Response To Title Ix And The Development Of Women\u27s Sports In The Big Ten Conference, 1972-1982

Signed into law in 1972, Title IX of the Education Amendments was designed to eliminate gender discrimination throughout the American educational system. Title IX applied to all educational programs at any level of schooling including admissions, financial aid, academic programs, and social organizations. However, Title IX has primarily been associated with college sports. Since 1972, female participation in intercollegiate athletics has increased dramatically. Yet additional opportunities for women in sports have not come easily. Significant battles between university leaders and the government about how this piece of legislation was to be enforced have persisted throughout the decades since passage of Title IX. The first ten years after Title IX was enacted marked the height of controversy over women\u27s athletics and gender equality. The Title IX Era (1972-1982) in the Big Ten clearly highlighted the practical challenges of achieving gender equity in athletics. While certain administrators undoubtedly held chauvinistic positions, it is equally clear that these attitudes were not the sole reason for the slow development of women\u27s sports. The stilted growth of women\u27s athletics at these institutions was directly related to the financial and logistical burdens of adding an entirely new program. Thus, during the Title IX Era, Big Ten officials were less focused on limiting female participation in sports than on the legitimate practical issues they faced. More importantly, the controversy over Title IX also revealed the limits of government involvement in higher education. Big Ten leaders opposed the rules established by the Department of Health, Education, and Welfare (HEW) and rejected the notion that the federal government could tell them how to run their program. However, these same officials consistently argued that their opposition to HEW\u27s Title IX regulations did not mean that they were against the ideal of gender equality in athletics. Ultimately, response to Title IX in the Big Ten was based on administrators\u27 assertions that they supported the spirit of equality, while at the same time denouncing the letter of the law as dictated by the government

High-Precision Optical Measurement of the 2S Hyperfine Interval in Atomic Hydrogen

We have applied an optical method to the measurement of the 2S hyperfine interval in atomic hydrogen. The interval has been measured by means of two-photon spectroscopy of the 1S-2S transition on a hydrogen atomic beam shielded from external magnetic fields. The measured value of the 2S hyperfine interval is equal to 177 556 860(15) Hz and represents the most precise measurement of this interval to date. The theoretical evaluation of the specific combination of 1S and 2S hyperfine intervals D_21 is in moderately good agreement with the value for D_21 deduced from our measurement