Development of lubricating oils suitable for use with liquid oxidizers Final summary report, 4 Dec. 1969 - 4 Oct. 1970
Development of lubricating oils suitable for use with liquid oxidizers
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Development of lubricating oils suitable for use with liquid oxidizers
The author has identified the following significant results. Examination of sand samples from both dune and interdune areas at White Sands, New Mexico, indicates marked differences in composition and texture between these two types of facies. If these differences are characteristics of dune fields in general, information concerning them may help to explain the contrast in appearance of the two kinds of sand areas on ERTS imagery and to permit interpretation of similar features in remote areas, such as Saudi Arabia.
The author has identified the following significant results. The assembling of photomosaics from color prints of ERTS images has made possible the recognition and description of san patterns, and these are to be the basis of a worldwide classification of sand bodies. Progress has been as rapid as the acquisition of the bulk composite images will permit and for some areas the mosaics are now nearly complete. A second step, which consists of the accumulation and analysis of regional wind data, to be plotted as overlays for the dune patterns, is now underway and should soon give tangible results. Other aspects of the project include the gathering of ground truth in the form of air photographs, needed to interpret geomorphic forms and the sampling of sand deposits for analyzing the texture and composition of sand bodies. A start has been made on these studies in several selected areas.
A description and classification of major types of sand seas on the basis of morphological pattern and lineation are discussed. The steps involved in analyzing the patterns of deposits on ERTS-1 imagery, where the visible forms are mostly dune complexes rather than individual dunes are outlined. After completion of thematic maps portraying the pattern and lineation of the sand bodies, data on directions and intensity of prevailing and other winds are plotted on corresponding bases, as a preliminary to determination of internal structures through ground truth.
Fluorine containing esters of polycarboxylic acids are discussed. The use of these esters as extreme temperature lubricants and base fluids for greases is investigated.
Data are presented to show that tris(hydroxymethyl)acetic acid, monochloropentaerythritol, monofluoropentaerythritol, difluoropentaerythritol, monoaminopentaerythritol, and diaminopentaerythritol exhibit solid-state transitions to a plastic crystalline state. Transitional enthalpies in many of these substances are lower than might be expected by analogy with related structures, suggesting that some configurational contributions to their entropy increments have been inhibited.
The author has identified the following significant results. The regional studies of sand seas made possible by analysis of ERTS-1 imagery have established that widespread patterns of eolian sand deposition exist in many places and that similarities and differences in these patterns can be measured and compared, on a worldwide scale. Analysis of the relationships of depositional patterns to controlling factors will require completion of the color mosaics of the test sites, and acquisition of adequate supporting ground truth data, especially wind data. Once analyses are complete, the results will be applicable to the regional study of ancient eolian sandstones. Such sandstones were formed many millions of years ago under conditions believed to be identical to those under which the sand seas that are observed being formed today. The understanding of the deposition of eolian sands provided by analysis of ERTS-1 imagery will be applicable to an understanding of the structure and distribution of ancient eolian sandstones and their potential as reservoirs of oil and water.
The author has identified the following significant results. Recent acquisition of generally high quality color prints for most of the test sites has enabled this project to make significant advances in preparing mosaics of sand desert areas under study. Computer enhancement of imagery, where details of complex dune forms need to be determined, has been achieved with arrival of computer-compatible ERTS-1 tapes. Further, a comparator, recently received, gives precise visual measurements of width, length, and spacing of sand bodies and so improves comparison of patterns in various test sites. Considerable additional meteorological data recently received on sand-moving winds in China, Pakistan, Libya, and other study areas enabled much progress to be made in developing overlays for the dune mosaics. These data show direction, speed, and frequency of winds. Other new data for use in preparing overlays used with ERTS-1 image mosaics include ground truth on moisture control, geologic settings, and plant distribution. With the addition of visual observation data and prints from hand-held photography now being obtained by the Skylab 4 mission, much progress in interpreting the patterns of sand seas for 17 desert sites is anticipated.
The author has identified the following significant results. Recent acquisition of generally high quality color prints for most of the test sites has enabled the project to make significant advances in preparing mosaics of sand desert areas under study. Computer enhancement of imagery of selected sites, where details of complex dune forms need to be determined, has been achieved with arrival of computer-compatible ERTS-1 tapes. Further, a comparator, recently received, gives precise visual measurements of width, length, and spacing of sand bodies and so improves comparison of patterns in various test sites. Considerable additional meteorological data recently received on sand-moving winds in China, Pakistan, Libya and other areas enabled much progress to be made in developing overlays for the dune mosaics. These data show direction, speed, and frequency of winds. Other new data for use in preparing overlays used with ERTS-1 image mosaics include ground truth on moisture control, geologic settings, and plant distribution. With the addition of visual observation data and prints from hand-held photography now being obtained by the Skylab mission, much progress in interpreting the patterns of sand seas for 17 desert sites is anticipated.
There are no author-identified significant results in this report.
This study of sand seas on a global scale consists of identifying and measuring characteristic sand forms, examining structures, determining the processes involved, and ascertaining the world distribution of various types of sand bodies. Fifteen major areas or sites in the Eastern Hemisphere and three sites in the Western Hemisphere have been examined. In this study an attempt is made to develop a strictly objective classification of worldwide application. Ultimate objectives are threefold. First, a better understanding of stratification in ancient rocks of dune origin; such structures are important in the migration of water and oil. Second, a further insight into the controls of sand migration that in some areas adversely affects various enterprises of man may be obtained. Finally, an appreciation of certain similar patterns on Mars, apparently wind-formed, may result.
Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China.
A comparative study of Martian and terrestrial dunes was made based on Viking Orbiter pictures and aerial pictures of terrestrial deserts. The morphological similarity between the Martian dunes and terrestrial crescentic dunes implies that the dynamics of dune formation are similar on the two planets, despite Martian constraints on dune formation that include much higher velocity winds required to move 'sand' in saltation, the possible inhibition of sand movement by absorbed water vapor, the seasonal 'snow' cover in the north circumpolar erg, and a probably sparse sand supply. The absence of longitudinal dunes and the restriction of massive crescentic dunes to a few sites on Mars suggests that Mars may have a long eolian history in which much of the sand suitable for saltation has already been transported to the north polar erg and crater floor fields.
The Western Desert of Egypt is one of the most arid regions on earth and is probably the closest terrestrial analog to the surface of Mars. An expedition to the area in 1978 revealed an abundance of quartzite and basalt rocks that have been pitted and fluted by wind erosion and deflation of the desert surface. These pitted rocks are internally homogeneous, show no internal holes or vesicles, and are considered an important but neglected type of ventifact. They bear a striking resemblance to the pitted and fluted rocks seen by the Viking Landers, rocks that have generally been interpreted as vesicular basalts only slightly modified by wind erosion. Wind tunnel studies of the air flow over and around nonstreamlined hand specimens from the Western Desert show that windward abrasion coupled with negative flow, secondary flow, and vorticity in a unidirectional wind can explain the complex arrays of pits and flutes. These field and laboratory observations suggest that the pitted rocks at the Viking Lander sites are also ventifacts, and thus the Martian surface may be far more wind eroded than previously thought.
The Shuttle imaging radar (SIR-A) acquired images of a variety of the earth's geologic areas covering about 10 million square kilometers. Structural and geomorphic features such as faults, folds, outcrops, and dunes are clearly visible in both tropical and arid regions. The combination of SIR-A and Seasat images provides additional information about the surface physical properties: topography and roughness. Ocean features were also observed, including large internal waves in the Andaman Sea.
Previously unknown buried valleys, geologic structures, and possible Stone Age occupation sites have been revealed through the Shuttle Imaging Radar (SIR-A) penetration of the extremely dry Selima Sand Sheet, dunes and drift sand of the eastern Sahara. Radar penetration of dry sand and soils varies with the wavelength of the incident signals, which is 24 cm for the SIR-A system, as well as incidence angle and electrical properties of the material which are largely determined by moisture content. The calculated depth of radar penetration of dry sand and granules has been established to be 5 m on the basis of laboratory measurements of Selima Sand Sheet sample electrical properties. September 1982 field studies in Egypt have verified SIR-A signal penetration depths of at least 1 m in the Selima Sand Sheet and drift sand, and 2 m or more in sand dunes.
The fluvial and mass wasting origin of the particles in the eolian deposits, the segregation of these materials on the basis of grain size, and the migration of those particles capable of saltation to areas of accumulation in lowland basins of the Sahara are suggested as analogs for the formation and accumulation of 'sand' sheets and dunes on the northern plains and in the polar erg on Mars. Outliers of the Martian plateau in the fretted terrain are seen as having been dissected, at least initially, by channels whose upstream portions are incised in the uplands. The Martian 'wadis' possess many geomorphic peculiarities similar to those of the Gilf (Gilf Kebir Plateau, southwest Egypt) wadis, and like the Egyptian features they have been attributed to mass wasting. Even though basal sapping and removal of debris by wind have almost certainly modified the Martian features, their deep incision in the plateau and their inferred northward extensions in the northern plains are thought to require not only initial downcutting by fairly energetic streams but also prolonged and long-distance flow of water.
A correlation of known archaeologic sites with the mapped locations of the streamcourses is expected and may lead to new interpretations of early human history in the Sahara. The valley networks, faults, and other subjacent bedrock features mapped on the SIR-A images are promising areas for ground water and mineral exploration. Additionally, the analogies between the interplay of wind and running water in the geologic history of the Sahara and of Mars are strengthened by the SIR-A discoveries of relict drainage systems beneath the eolian veneer of Egypt and Sudan.