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Articles 8791 - 8820 of 8852

Full-Text Articles in Physical Sciences and Mathematics

Reaction, Wernher Von Braun Jul 1957

Reaction, Wernher Von Braun

Space Journal

No abstract provided.


A Study Of Current Noise In Cokes, Carbons, And Graphites, Robert J. Lanter Jun 1957

A Study Of Current Noise In Cokes, Carbons, And Graphites, Robert J. Lanter

Physics & Astronomy ETDs

This study shows that current noise occurs when there is a deviation of Ohm's Law, i.e., when the applied voltage and resultant current are no longer proportional. Since most, and perhaps all, cases of occurrence of frequency and current dependent noise are associated with non-linear devices, e.g., semiconductors, diodes, vacuum tubes, insulators near breakdown, it seems reasonable to seek a mechanism involving non-linearity as an important feature. Even though it may not be justifiable to seek a single mechanism to explain all of the occurrences of current noise, nevertheless, the fact that in cases studied and discussed herein …


A Cloud Chamber Study Of Penetrating Showers In Aluminum, Copper And Lead, James Francis Kenney Jun 1957

A Cloud Chamber Study Of Penetrating Showers In Aluminum, Copper And Lead, James Francis Kenney

Physics & Astronomy ETDs

In recent years, much work has been done in the investigation of high-energy nuclear collisions in various materials. The purpose of these investigations is to gain a better understanding of nucleon-meson-nucleon interactions at high energies. Laboratory accelerating devices are capable at the present time of attaining energies which are still very low in comparison to the upper limit of the cosmic radiation energy spectrum. As a result, these investigations are best carried out by using the very hard component of the cosmic radition as the primary particle of the collision.


A Pulse Length Analyzer, Paul Scheie Jun 1957

A Pulse Length Analyzer, Paul Scheie

Physics & Astronomy ETDs

For experiments involving small scintillators and for experiments involving scintillator telescopes, the circuitry may closely resemble that used with geiger counters. However, if it is desired to make use of the variation in the signal amplitude in a large scintillator, some means must be found to deal with a wide range of amplitudes. The scintillator employed in the experiment to which this work relates is a tank 10 feet in diameter that contains 300 gallons of activated toluene; light of the scintillations is collected by a 16 inch photo-multiplier tube that is located on top of the tank.


A Chemical Ozone Measuring Radio Sonde, Alan W. Peterson Jun 1957

A Chemical Ozone Measuring Radio Sonde, Alan W. Peterson

Physics & Astronomy ETDs

The Vertical distribution of atmospheric ozone has been determined spectroscopically either from surface observations or from balloon-borne spectrographs sent aloft. These spectrographic techniques have several disadvantages. Surface observations of the "Umkehr Effect" give only a rough distribution, four or five points for the entire atmosphere.


The Vertical Gradients Of Ozone Concentration And Its Relation To The Eddy Coefficient Of Diffusion, Joseph Levine May 1956

The Vertical Gradients Of Ozone Concentration And Its Relation To The Eddy Coefficient Of Diffusion, Joseph Levine

Physics & Astronomy ETDs

The purpose of this thesis is to apply this method to a tentative evaluation of the eddy coefficient of diffusion. Actually the investigation was more specifically an attempt to relate the difference in ozone concentration between the two stations to the average wind shear and to the vertical thermal stability.


An Indicator Of Position With Respect To The Earth's Magnetic Field, Lloyd C. Nielsen May 1956

An Indicator Of Position With Respect To The Earth's Magnetic Field, Lloyd C. Nielsen

Physics & Astronomy ETDs

A large amount of experimental research in the field of atmospheric physics involves carrying apparatus aloft by means of balloons. Data from balloon-borne instruments may be obtained either by recovery of the apparatus or by radio telemetering during the flight. Of these two methods, the latter is of course the more convenient and reliable, since recovery of the apparatus is time-consuming and often impossible.


The Motion Of A Charged Particle In Homogenous Time-Varying Magnetic Field, Thomas R. Bates May 1956

The Motion Of A Charged Particle In Homogenous Time-Varying Magnetic Field, Thomas R. Bates

Physics & Astronomy ETDs

This paper will discuss the motion of a non-relativistic, non-radiating charged particle in an infinite homogeneous magnetic field which varies linearly with time. We shall assume the motion to be confined to a plane perpendicular to the magnetic field.


The Mathematical Theory Of Meteorite Penetration Into Earth-Targets, Richard D. George May 1955

The Mathematical Theory Of Meteorite Penetration Into Earth-Targets, Richard D. George

Physics & Astronomy ETDs

A problem in mathematical ballistics of fundamental importance in meteoritics is investigated in this thesis, namely the problem of estimating the speed at which a meteorite of assigned shape, mass and density struck a specific earth-target, either from purely theoretical considerations or from penetration or other impact-effects actually observed and measured in the earth-target.

In the second chapter several methods for calculating impact-velocities based on terminal ballistic theory are developed. While some of these methods can be successfully applied to as many as 63 recovered meteorites, others are applicable only to a very few known meteorites because of the failure …


An Experiment Of The Time Variations Of Cosmic Rays Underground, Mercedes Merner Agogino Oct 1954

An Experiment Of The Time Variations Of Cosmic Rays Underground, Mercedes Merner Agogino

Physics & Astronomy ETDs

Ever since the discovery of cosmic rays, investigations of time variations in their intensity have been carried out in the hope of obtaining information on their nature and origin. Early experiments were somewhat contradictory, but it was soon clear that any variation present could be no longer than a few percent at the most. This meant that experiments had to be carefully planned and carried out over a long period of time to attain the statistical accuracy necessary for clear-cut results. In addition, the influence of the atmosphere and the earth's magnetic field made it very difficult to interpret the …


The Measurement Of The Concentration Of Ozone In The Atmosphere By The Oxidation Of Silver, Albert Goodman Oct 1954

The Measurement Of The Concentration Of Ozone In The Atmosphere By The Oxidation Of Silver, Albert Goodman

Physics & Astronomy ETDs

Under conditions of standard temperature and pressure, it has been found that no reaction occurs between silver and oxygen, nor between silver and ozone. When the temperature of the silver is raised, however, it is oxidized by ozone but not by oxygen. Upon raising the products of the reaction to a still higher temperature, they decompose into silver and ordinary oxygen. By measuring the amount of oxygen thus produced, it would be possible to calculate the amount of ozone involved originally.


The Structure Of A Shock Front In Argon, John W. Bond Jr. Jul 1954

The Structure Of A Shock Front In Argon, John W. Bond Jr.

Physics & Astronomy ETDs

If a one-dimensional shock wave travels through argon, the translational degrees of freedom of the atoms are immediately excited and reach translational equilibrium within two collision lengths. If the shock velocity is sufficiently high, energy will be transferred from the translational degrees of freedom to those of electronic excitation and ionization until complete thermal equilibrium exists. The region between the first disturbance in front of the shock and the point at which thermal equilibrium is first realized is the shock front.


Cosmic Ray Intensity At Balloon Altitudes, Kenneth R. Greider May 1954

Cosmic Ray Intensity At Balloon Altitudes, Kenneth R. Greider

Physics & Astronomy ETDs

In the investigation of cosmic rays at balloon altitudes, it is important to recognize the various factors that affect the total intensity at any point in the atmosphere. The three main factors are: (1) Atmospheric influence: variation of intensity with atmospheric depth, (2) Geomagnetic influences: variations of intensity with the geomagnetic latitude, and (3) Extraterrestrial influences: periodic and non periodic variations of intensity.


Diffuse Reflection Of Light, Francis L. Bentsen May 1954

Diffuse Reflection Of Light, Francis L. Bentsen

Physics & Astronomy ETDs

This thesis describes an attempt to determine the feasibility of measuring the ozone content in the air by absorption of light over a long path.


Analysis Of Zodiacal Light Recordings, Mclane Downing May 1954

Analysis Of Zodiacal Light Recordings, Mclane Downing

Physics & Astronomy ETDs

The object of the zodiacal light work at Capillo Peak is to take comparable records of zodiacal light intensities over an extended period of time. In order to obtain extra-terrestrial isophotes from the original recordings, corrections for loss of light intensity in the atmosphere must be made.


An Investigation Of The Collision Lengths Of Penetrating-Shower-Producing Radiation In Various Materials, James Francis Kenney May 1953

An Investigation Of The Collision Lengths Of Penetrating-Shower-Producing Radiation In Various Materials, James Francis Kenney

Physics & Astronomy ETDs

The purpose of this paper is to compile and tabulate some of the experimental data that have been obtained on penetrating showers, and to compare these data with the results that should be expected from the various theories that have been advanced.


On Air Density Measurements Using The Alpha-Particle Range Method, Gus Tom Zorn May 1953

On Air Density Measurements Using The Alpha-Particle Range Method, Gus Tom Zorn

Physics & Astronomy ETDs

The density of the air is in general determined from a knowledge of the pressure and temperature by applying the ideal gas law. This law may be stated in the following for; p=MP/TR, where p is the density of the air in gm/cm3, M is the gram molecular weight, P is the pressure in dynes/cm2, T is the temperature in degrees kelvin and R is the universal gas constant in ergs per degree absolute for one mole. This method is also used in the determination of the air density as a function of the height in …


Sunrise And Sunset Times For May-June 1952 Mar 1953

Sunrise And Sunset Times For May-June 1952

Journal of the Department of Agriculture, Western Australia, Series 3

Supplied by the Government Astronomer

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on …


Sunrise And Sunset Times For March-April, 1953 Jan 1953

Sunrise And Sunset Times For March-April, 1953

Journal of the Department of Agriculture, Western Australia, Series 3

State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on a hill it would appear earlier.

[Supplied by the Government Astronomer]


Sunrise And Sunset Tables Times For Jan.-Feb., 1953 Nov 1952

Sunrise And Sunset Tables Times For Jan.-Feb., 1953

Journal of the Department of Agriculture, Western Australia, Series 3

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on a hill it would appear …


Sunrise And Sunset Tables Sep 1952

Sunrise And Sunset Tables

Journal of the Department of Agriculture, Western Australia, Series 3

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on a hill it would appear …


Sunrise And Sunset Times For Sept.-Oct., 1952 Jul 1952

Sunrise And Sunset Times For Sept.-Oct., 1952

Journal of the Department of Agriculture, Western Australia, Series 3

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun s disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on a hill it would …


Sunrise And Sunset Times For July - Aug., 1952 May 1952

Sunrise And Sunset Times For July - Aug., 1952

Journal of the Department of Agriculture, Western Australia, Series 3

(Supplied by the Government Astronomer)

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on …


Sunrise And Sunset Times For May-June, 1952 Mar 1952

Sunrise And Sunset Times For May-June, 1952

Journal of the Department of Agriculture, Western Australia, Series 3

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on a hill it would appear …


Sunrise And Sunset Times For March-April 1952 Jan 1952

Sunrise And Sunset Times For March-April 1952

Journal of the Department of Agriculture, Western Australia, Series 3

Times of sunrise and sunset for every fifth day, are given for a number of towns throughout the State. Times for a town not on the list may be estimated if its position in relation to one or more of the listed towns is known. The times given for sunrise are those of the first appearance of the top edge of the sun over a true horizon; those for sunset give the time of the sun's disappearance below a true horizon. Situation in a valley would make the sun appear to rise later, and on a hill it would appear …


Investigation Of Penetrating Cosmic-Ray Showers In Water, George William Rollosson Sep 1951

Investigation Of Penetrating Cosmic-Ray Showers In Water, George William Rollosson

Physics & Astronomy ETDs

In this investigation, some of the properties of the radiation which produces penetrating showers in its passage through matter are studied. Geiger techniques are used to measure the average distance over which the neutral radiation produces one penetrating shower. This distance, called collision length, is measured in water...

The collision length, on the other hand, is measured by placing the material near the apparatus and measuring the mean distance in which one shower is produced and eliminating from the observation any penetrating showers which may be produced subsequently either (a) by the original particle or (b) by the secondaries from …


An Experimental Investigation Of The Dead Time Of Geiger-Mueller Counters, Peter H. Jessner Sep 1951

An Experimental Investigation Of The Dead Time Of Geiger-Mueller Counters, Peter H. Jessner

Physics & Astronomy ETDs

As ever more sensitive and precise experiments are being performed with Geiger Counters, especially in cosmic ray research, the resolving power of these instruments assumes an ever increasing importance. With the present perfection of electronic circuitry, this resolving time has become largely a function of the dead time of the Geiger counter tube itself. It was therefore proposed to investigate methods of reducing this dead time. Only self-quenching counter tubes had to be considered in this connection since the dead time of all other types of Geiger counters is inherently longer.


A Sensitive Electronic Photometer Employing Negative Feedback, John Lee Pack Sep 1951

A Sensitive Electronic Photometer Employing Negative Feedback, John Lee Pack

Physics & Astronomy ETDs

Purpose of the Instrument

The instrument to be described in these pages was tentatively intended to be used for the purpose of scanning the night sky automatically for investigations of the zodiacal light. It was to detect light below the noise level of a photomultiplier tube, to have linearity up to signals 100 times greater than the noise level, and to have a response time of about 10-4 seconds.


The Elastic Scattering Of Deuterons By Deuterons, Richard John Runge Sep 1951

The Elastic Scattering Of Deuterons By Deuterons, Richard John Runge

Physics & Astronomy ETDs

The concern of this work is the calculation of elastic scattering of deuterons by deuterons. The solution of the problem will be given in the usual center of mass system of coordinates, the conversion of results from this to the laboratory system being standard. Since the deuteron itself consists of a neutron and a proton, the problem is thus one of four bodies. The nuclear three body problem of the scattering of a neutron by a deuteron has been treated by previous authors and we will have occasion to employ methods used by these authors extending them to the four …


A Differential Electronic Photometer And Polariscope With Negative Feedback, William Rogers Jun 1951

A Differential Electronic Photometer And Polariscope With Negative Feedback, William Rogers

Physics & Astronomy ETDs

In connection which a program of research in the physics of the atmosphere, a need has arisen for a sensitive differential photometer which would be adaptable to balloon-borne operation. This paper describes a prototype of such an instrument. The present photometer is constructed for preliminary investigations to be carried out in the laboratory, but with light weight components used in the design except for the power supply and the main structural frame. Consideration is given to these latter features to the extent that the entire equipment is designed for operation from power sources which can be directly replaced by small …