Recertification of the air and methane storage vessels at the Langley 8-foot high-temperature structures tunnel

This center operates a number of sophisticated wind tunnels in order to fulfill the needs of its researchers. Compressed air, which is kept in steel storage vessels, is used to power many of these tunnels. Some of these vessels have been in use for many years, and Langley is currently recertifying these vessels to insure their continued structural integrity. One of the first facilities to be recertified under this program was the Langley 8-foot high-temperature structures tunnel. This recertification involved (1) modification, hydrotesting, and inspection of the vessels; (2) repair of all relevant defects; (3) comparison of the original design of the vessel with the current design criteria of Section 8, Division 2, of the 1974 ASME Boiler and Pressure Vessel Code; (4) fracture-mechanics, thermal, and wind-induced vibration analyses of the vessels; and (5) development of operating envelopes and a future inspection plan for the vessels. Following these modifications, analyses, and tests, the vessels were recertified for operation at full design pressure (41.4 MPa (6000 psi)) within the operating envelope developed

Wide band frequency tracker performance and design of an all angle laser Doppler optical homodyne receiver, ground wind and wind tunnel measurements program, volume 2 Final report

Analysis and measurement of characteristics of wide band frequency trackers and design and fabrication of all angle laser Doppler velocimete

Economics of Transporting Poultry Litter from Northwest Arkansas to Eastern Arkansas Croplands

Applying baled litter from northwest Arkansas shipped by truck with backhauls, supplemented with chemical fertilizers provided the most cost-efficient method to supply nutrients to crops in eastern Arkansas, according to a GAMS optimization. Shipping raw litter by truck and barge is the optimal choice when backhauls or baling is unavailable.Public Economics,

A Survey of Acidity in Drainage Waters and the Condition of Highway Drainage Installations

Every creek gulley and raw interrupted by roadway fills and embankments must be provided with an adequate drainage conduit under the pavement. If the natural drainage is impeded or the conduit is not functioning properly, impounded water over-runs the pavement, seeps through the fill, and eventually disintegrates the section or reduces its stability. The topography in Kentucky, through varied sectionally, requires on the average, one cross-drain for every thousand feet of roadway. Obviously, these drainage structures are of considerable economic importance in the highway program, not only from the standpoint of initial construction costs, but also from consideration of the service-efficiency or the permanence of the installation itself. Of these two factors, service-efficiency is undoubtedly the more important factor in determining an integrated service economy. Since permanence of a culvert or cross-drain depends largely on the specific properties of the material with which it is made, considerable advantage may be derived by selecting material for use in areas where their properties are compatible with the conditions of service, and excluding them where condition are known to be unfavorable

Development and flight tests of vortex-attenuating splines

The ground tests and full-scale flight tests conducted during development of the vortex-attenuating spline are described. The flight tests were conducted using a vortex generating aircraft with and without splines; a second aircraft was used to probe the vortices generated in both cases. The results showed that splines significantly reduced the vortex effects, but resulted in some noise and climb performance penalties on the generating aircraft

Foundations Performance of Large Diameter Tanks

The paper presents a detailed case history of foundation performance of six 60-m diameter, 15-m high, floating roof fuel oil tanks and six 96.8-m diameter, 20-m high, fixed roof process water tanks built for a large power plant. Tank walls were supported by concrete ringwall footings. General subsurface conditions at the site are discussed, along with proposed site grading and the rationale for tank foundation selection. Because vibro-replacement improvement of site soils had been used beneath settlement-sensitive structures, there was skepticism regarding the decision to support the tanks on unimproved soils. To allay doubts about the adequacy of tank foundation performance, a staged hydrotesting procedure and an extensive settlement monitoring program were developed and implemented. The excellent tank hydrotesting results demonstrated that ground improvement was not needed due to the more settlement-tolerant nature of the tanks

Accelerated Consolidation of Soft Clays Using Wick Drains

Construction of the New Istana for the Sultan of Brunei required that fill slopes up to 85 feet high be placed on very soft compressible floodplain soils. Wick drains installed in the soft sediments accelerated their consolidation and reduced long-term settlements. The consolidation also produced a strength increase in the soft soils that allowed the fill to be constructed without danger of a major base slip failure. Instrumentation installed in the floodplain soils provided data on excess porepressures built up during the fill placement, and on the resulting settlements. The measured porepressures and settlements were in good agreement with the predicted values

Movements Around Transit Tunnels in Mixed Ground

This paper describes the ground movements measured at a Test Section during construction of twin rapid transit tunnels in Cambridge, Massachusetts. The Test Section was located in an area of rock, soft ground and mixed face tunneling, with the alignment of the twin tunnels approximately 100 feet below ground surface. Overburden soils consist primarily of a very dense, saturated glacial till containing cobbles and boulders, with a weakly metamorphosed, fractured shale bedrock below. Instrumentation at the Test Section was installed in three cross-sections: one with the tunnel headings entirely in rock, a second with the tunnel headings in soft ground, and a third in a mixed face area. The field measurements are analyzed to show the effects of ground losses at the tunnel headings vs. distance away from headings, the effects of single vs. twin tunnel construction, and the effects of mixed face vs. rock and soft ground tunneling on ground movements

Electromagnetic Pulse Sounding for Surveying Underground Water

This project supported in part by the Office of Water Resources Research U. S. Department of the Interior Washington, D. C. under Project B-028-OHIOA number of approaches have been explored for measuring the water content of soil electrically. In contrast with traditional measurements, which utilize electric currents at DC or at specific frequencies, our techniques have been based on the transmission and reflection of sharp, regularly repeated pulses. Such pulse measurements can be shown to be equivalent to measuring the electrical properties at all frequencies in a very wide band, and therefore the possibility of extracting the desired information is much greater than with single-frequency measurements. Because the information content of the signal is great, data processing can be used to extract those features which relate most directly to moisture content and reject those which appear to depend more on soil inhomogenieties. For example, it was found that the attenuation in the frequency band of approximately 10 to 20 MHz had a much higher correlation with soil moisture than that in other frequency bands for the actual field conditions under which our measurements were made. This information content increase is obtained by means of sophisticated research equipment. The measurements reported herein were made and processed under real-time computer control. They include the signal scattered from known buried targets, transmission measurements through the ground, and the measurement of reflections in a coaxial test cell, all with pulses containing very wide frequency bands. The results are encouraging in that definite correlations with moisture were found. Unfortunately the one-year time limitation of this effort, much of it spent in instrumentation development, was insufficient to allow testing these correlations quantitatively over extended time periods or in a variety of locations. Thus the techniques must be evaluated at present as promising, but not fully proven. It should be noted that, while the research system to obtain this information is complex, field equipment based on these techniques need not be unduly complicated or expensive. Once the features relating to moisture content under the greatest variety of field conditions are identified, means for extracting this information more simply should be devised. This is proposed as the objective for continuation of this effort.Summary -- Introduction -- 1. The Measuring System -- 2. Data Processing -- 3. Underground Moisture Content Monitoring by Measurement of Buried Target Signatures -- 4. Sampled Moisture Conditions -- 5. Underground Propagation Experiment -- 6. Reflection Measurements on Soil Samples in a Vertical Coaxial Test Cell -- 7. Propagation Calculations -- Conclusions -- Recommendations -- References -- Appendix I - Transmission Measurements using a Buried Antenn