Low subsonic dynamic-stability investigation of several planetary-entry configurations in a vertical wind tunnel, part i

Low subsonic dynamic stability data for evaluation of ballistic deceleration vehicle entering Mars atmospher

A laser scanner for 35mm film

The design, construction, and testing of a laser scanning system is described. The scanner was designed to deliver a scanned beam over a 2.54 cm by 2.54 cm or a 5.08 cm by 5.08 cm format. In order to achieve a scan resolution and rate comparable to that of standard television, an acousto-optic deflector was used for one axis of the scan, and a light deflecting galvanometer for deflection along the other axis. The acoustic optic deflector has the capability of random access scan controlled by a digital computer

Solar pumped laser

A solar pumped laser is described in which the lasant is a gas that will photodissociate and lase when subjected to sunrays. Sunrays are collected and directed onto the gas lasant to cause it to lase. Applications to laser propulsion and laser power transmission are discussed

Laser Doppler dust devil measurements

A scanning laser doppler velocimeter (SLDV) system was used to detect, track, and measure the velocity flow field of naturally occurring tornado-like flows (dust devils) in the atmosphere. A general description of the dust devil phenomenon is given along with a description of the test program, measurement system, and data processing techniques used to collect information on the dust devil flow field. The general meteorological conditions occurring during the test program are also described, and the information collected on two selected dust devils are discussed in detail to show the type of information which can be obtained with a SLDV system. The results from these measurements agree well with those of other investigators and illustrate the potential for the SLDV in future endeavors

Magnetomotive drive and detection of clamped-clamped mechanical resonators in water

We demonstrate magnetomotive drive and detection of doubly clamped string resonators in water. A compact 1.9 T permanent magnet is used to detect the fundamental and higher flexural modes of $\mathrm{200 \mu m}$ long resonators. Good agreement is found between the magnetomotive measurements and optical measurements performed on the same resonator. The magnetomotive detection scheme can be used to simultaneously drive and detect multiple sensors or scanning probes in viscous fluids without alignment of detector beams.Comment: 4 pages, 3 figure

Issues in providing a reliable multicast facility

Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast

Native Midwestern Pastures: Their Origin, Composition, and Degeneration

According to Doctor J. E. Weaver and Mr. W. W. Hansen the purpose of this bulletin is to present certain facts involved in range and pasture management by outlining in some detail the fundamental phenomenon of vegetational change upon which all rational pasture studies must be based. They maintain that the native prairie vegetation is an organic entity in close adjustment with soil and climate, which has developed gradually to its present condition of dynamic stabilization. When the prairie is grazed and trampled, various changes occur, the nature and extent of which vary somewhat directly with the degree of disturbance, but under protection or deferred grazing, repair of moderate damage normally occurs rapidly. Once degeneration of the prairie is well under way, however, it proceeds so gradually and effectively that it is usually not observed until great loss in productivity is sustained, and several years are required for recovery. The stages in degeneration, how and why they occur, the types of pasture that are produced, and causes of complete disintegration are fully outlined and illustrated in this bulletin, which states that a knowledge of the stages of prairie degeneration affords a scientific basis for planned range improvement and pasture management. Doctor Weaver is eminently fitted by long study of grasslands in the midwestern and far western states to understand and analyze the problems of grazing native pastures. His scientific training is tempered by an unusual interest in the application of scientific facts to practical problems of crop production. He knows that native forage produced in pastures is an important crop largely within the control of man, a fact greatly emphasized by the recent drought. This crop may be decreased or increased next year and the next, depending much upon the present treatment of the range. This bulletin on the fundamental, underlying principles of the origin, composition, and deterioration of native midwestern pastures is to be followed by one recording extensive experiments on the improvement of pasture under protection. (99 pages

A preliminary training guide for utilizing high-altitude, color-infrared photography in compiling soil maps

Instruction for acquiring and analytically processing small-scale color-infrared photography to perform a soil resources inventory over forests of the southern U.S. is provided. Planning the project; acquiring aerial photography, materials, equipment and supplemental data; and preparing the photography for analysis are discussed. The procedures for preparing ancillary and primary component overlays are discussed. The use of correlation charts and dichotomous keys for mountain landforms, water regime, and vegetation is explained

Laser Doppler technology applied to atmospheric environmental operating problems

Carbon dioxide laser Doppler ground wind data were very favorably compared with data from standard anemometers. As a result of these measurements, two breadboard systems were developed for taking research data: a continuous wave velocimeter and a pulsed Doppler system. The scanning continuous wave laser Doppler velocimeter developed for detecting, tracking and measuring aircraft wake vortices was successfully tested at an airport where it located vortices to an accuracy of 3 meters at a range of 150 meters. The airborne pulsed laser Doppler system was developed to detect and measure clear air turbulence (CAT). This system was tested aboard an aircraft, but jet stream CAT was not encountered. However, low altitude turbulence in cumulus clouds near a mountain range was detected by the system and encountered by the aircraft at the predicted time

The Environment of the Prairie

Contribution from the Botanical survey of Nebraska, New series, no. 6."Literature cited": p. 50.Mode of access: Internet