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Mechanical sieve consists of three horizontal screens mounted in a vertical stack. A combination of rotation and tapping produces an even flow across the screens, dislodges trapped particles, an ensures rapid segregation of the sample.
Electron microscope-thin film microprobe techniques in biomaterial studies of chemical segregation, species diffusion and small particle analysis
Demonstration was performed to experimentally assess the potential advantages in the processing of materials in space, and specifically, to determine the effects of lack of density segregation and heat convection in the weightless environment of space.
An ion microprobe and a laser microprobe were used to measure concentrations of corrosion-produced hydrogen on a microscopic scale. Hydrogen concentrations of several thousand ppm were measured by both analytical techniques below the fracture surfaces of hot-salt stress-corroded titanium alloy specimens. This segregation of hydrogen below fracture surfaces supports a previously proposed theory that corrosion-produced hydrogen is responsible for hot-salt stress-corrosion embrittlement and cracking of titanium alloys. These advanced analytical techniques suggest great potential for many areas of stress-corrosion and hydrogen embrittlement research, quality control, and field inspection applications.
Sliding friction and wear experiments were conducted with ternary ordered alloys of iron and cobalt containing various amounts of silicon to 5 weight percent. The friction and wear of these alloys were compared to those for binary iron-cobalt alloys in the ordered and disordered states and to those for the conventionally used bearing material, 440-C. Environments in which experiments were conducted included air, argon, and 0.25percent stearic acid in hexadecane. Results indicate that a ternary iron - cobalt - 5-percent-silicon alloy exhibits lower friction and wear than the simple binary iron-cobalt alloy. It exhibits lower wear than 440-C in all three environments. Friction was lower for the alloy in argon than in air. Auger analysis of the surface of the ternary alloy indicated segregation of silicon at the surface as a result of sliding.
The purpose of the demonstration was to show that mixtures of materials of different specific gravities would remain stable in the liquid state and during freezing in low g and not segregate as they do on earth. An inflight demonstration was performed on the Apollo 14 mission during the translunar and and transearth coast periods. The apparatus consisted of an electrical heater, a heat sink device for cooling, and sealed metal capsules containing matrix materials having a low-melting point and dispersants. The evaluation of the demonstration samples was accomplished by comparing space processed (flight) samples with (control) samples processed on the ground under otherwise similar conditions. In the low q environment of space flight the dispersions of particles, fibers, and gases in a liquid metal matrix were maintained during solidification. Dispersions of normally immiscible liquids were also maintained during solidification.
An area-navigation method for automatic control of aircraft arriving in a random fashion from the en-route centers to the near terminal area is proposed. Control is exercised by a ground computer that sequences and schedules the aircraft. Altitude segregation is used to separate aircraft in velocity classes. Merging of all aircraft occurs near the outer marker. The merging region is designed so that no near misses will occur if the aircraft follow the assigned trajectories.
Suggestion that Fe-S (fescon) segregation plays a major role in the early chemical and physical history not only of the moon but of other terrestrial planets as well. A model of early lunar differentiation is described which can be tested in future lunar missions. Seismic studies bearing on the interior structure of the moon should in principle detect the Fe-S layer and the fescons.
Use of an ion microprobe and a laser microprobe to measure concentrations of corrosion-produced hydrogen on a microscopic scale. Hydrogen concentrations of several thousand ppm were measured by both analytical techniques below corroded and fracture surfaces of hot salt stress corroded titanium alloy specimens. This extremely high concentration compares with only about 100 ppm hydrogen determined by standard vacuum fusion chemical analyses of bulk samples. Both the ion and laser microprobes were used to measure hydrogen concentration profiles in stepped intervals to substantial depths below the original corroded and fracture surfaces. For the ion microprobe, the area of local analysis was 22 microns in diameter and for the laser microprobe, the area of local analysis was about 300 microns in diameter. The segregation of hydrogen below fracture surfaces supports a previously proposed theory that corrosion-produced hydrogen is responsible for hot salt stress corrosion embrittlement and cracking of titanium alloys. These advanced analytical techniques suggest great potential for many areas of stress corrosion and hydrogen embrittlement research, quality control, and field inspection of corrosion problems. For example, it appears possible that a contour map of hydrogen distribution at notch roots and crack tips could be quantitatively determined. Such information would be useful in substantiating current theories of stress corrosion and hydrogen embrittlement.
Development of an arrival air-traffic management system for a single runway. Traffic is segregated throughout most of the near terminal area according to performance characteristics. Nominal approach routes for each class of aircraft are determined by an optimization procedure. In this fashion, the nominal approach routes are dependent upon and, hence, determined by the near terminal area operating capabilities of each class of aircraft. The landing order and spacing of aircraft on the common approach path are determined so that a measure of total system deviation from the nominal landing times is minimized and safety standards are met. Delay maneuvers required to satisfy sequencing needs are then carried out in a manner dependent upon the particular class of aircraft being maneuvered. Finally, results are presented to illustrate the effects of the rate of arrivals upon a one-runway system serving three different classes of aircraft employing several different sequencing strategies and measures of total system deviation.
It is assumed that most of the igneous rocks on the lunar surface are the product of partial melting in the lunar interior, followed by segregation and upward transport of an igneous liquid. An attempt is made to determine constraints on the composition of the lunar interior that derive from the chemical composition of the lunar igneous rocks. The salient chemical characteristics of igneous rocks from the lunar surface are summarized, and are compared to analogous characteristics of terrestrial volcanic rocks so that major similarities and differences between terrestrial and lunar basaltic rocks can be established.
Surface research tools such as LEED, Auger emission spectroscopy analysis, and field ion microscopy are discussed. Examples of their use in studying adhesion, friction, wear, and lubrication presented. These tools have provided considerable insight into the basic nature of solid surface interactions. The transfer of metals from one surface to another at the atomic level has been observed and studied with each of these devices. The field ion microscope has been used to study polymer-metal interactions and Auger analysis to study the mechanism of polymer adhesion to metals. LEED and Auger analysis have identified surface segregation of alloying elements and indicated the influence of these elements in metallic adhesion. LEED and Auger analysis have assisted in adsorption studies in determining the structural arrangement and quantity of adsorbed species present in making an understanding of the influence of these species on adhesion possible. These devices are assisting in the furtherance of understanding of the fundamental mechanism involved in the adhesion, friction, wear, and lubrication processes.
The author has identified the following significant results. Significant results of the Wyoming investigation during the first six months include: (1) successful segregation of Precambrian metasedimentary/metavolcanic rocks from igneous rocks; (2) discovery of iron formation within the metasedimentary sequence; (3) mapping of previously unreported tectonic elements of major significance; (4) successful mapping of large scale fractures of the Wind River Mountains; (5) sucessful distinction of some metamorphic, igneous, and sedimentary lithologies by color-additive viewing of ERTS images; (6) mapping and interpretation of glacial features in western Wyoming; and (7) development of techniques for mapping small urban areas.
The author has identified the following significant results. Signigicant results have been obtained from the analyses of ERTS-1 imagery from five cycles over Test Site SR 124 by classical photointerpretation and by an interactive hybrid multispectral information extraction system (GEMS). Photointerpretation has produced over 25 overlays at 1:1,000,000 scale depicting regional relations and urban structure in terms of several hundred linear and areal features. A possible new fault lineament has been discovered on the northern slope of the Santa Monica mountains. GEMS analysis of the ERTS-1 products has provided new or improved information in the following planning data categories: urban vegetation; land cover segregation; manmade and natural impact monitoring; urban design; land suitability. ERTS-1 data analysis has allowed planners to establish trends that directly impact planning policies. For example, detectable grading and new construction sites quantitatively indicated the extent, direction, and rate of urban expansion which enable planners to forecast demand and growth patterns on a regional scale. This new source of information will not only assist current methods to be more efficient, but permits entirely new planning methodologies to be employed.
Optimal flow control and sequencing of air traffic operations in the near terminal area are discussed. The near terminal area model is based on the assumptions that the aircraft enter the terminal area along precisely controlled approach paths and that the aircraft are segregated according to their near terminal area performance. Mathematical models are developed to support the optimal path generation, sequencing, and conflict resolution problems.
Significant results have been obtained from the analyses of ERTS-1 imagery from five cycles over Test Site SR 124 by classical photointerpretation and by an interactive hybrid multispectral information extraction system (GEMS). The synopticity, periodicity and multispectrality of ERTS coverage, available for the first time to LA County planners, have opened up both a new dimensionality in data and offer new capability in preparation of planning inputs. Photointerpretation of ERTS images has produced over 25 overlays at 1:1,000,000 scale depicting regional relations and urban structure in terms of several hundred linear and areal features. To mention only one such result, a possible new fault lineament has been discovered on the northern slope of the Santa Monica mountains in the scene 1144-18015, composited of MSS bands 4, 5, 6,. GEMS analysis of the ERTS products has provided new or improved information in the following planning data categories: urban vegetation; land cover segregation; man-made and natural impact monitoring; urban design; and suitability. ERTS data analysis has allowed planners to establish trends that directly impact planning policies. This new source of information will not only assist current methods to be more efficient, but permits entirely new planning methodologies to be employed.
The author has identified the following significant results. Significant results of the Wyoming ERTS-1 investigation during the first six months (July-December 1972) included: (1) successful segregation of Precambrian metasedimentary/metavolcanic rocks from igneous rocks, (2) discovery of iron formation within the metasedimentary sequence, (3) mapping of previously unreported tectonic elements of major significance, (4) successful mapping of large scale fracture systems of the Wind River Mountains, (5) successful distinction of some metamorphic, igneous, and sedimentary lithologies by color additive viewing, (6) mapping of large scale glacial features, and (7) development of techniques for mapping small urban areas.
Methods of eliminating or reducing underbread cracking in multipass GTA welds in thick T-111 plate were studied. Single V butt welds prepared using experimental filler metal compositions and standard weld procedures resulted in only moderate success in reducing underbread cracking. Subsequent procedural changes incorporating manual welding, slower weld speeds, and three or fewer fill passes resulted in crack-free single V welds only when the filler metal was free of hafnium. The double V joint design with successive fill passes on opposite sides of the joint produced excellent welds. The quality of each weld was determined metallographically since the cracking, when present, was very slight and undetectable using standard NDT techniques. Tensile and bend tests were performed on selected weldments. The inherent filler metal strength and the joint geometry determined the strength of the weldment. Hardness and electron beam microprobe traverses were made on selected specimens with the result that significant filler metal-base metal dilution as well as hafnium segregation was detected. A tentative explanation of T-111 plate underbread cracking is presented based on the intrinsic effects of hafnium in the weldment.