Acid dissolution experiments: carbonates and the 6.8-micrometer bands in interplanetary dust particles

A chemical dissolution experiment on an interplanetary dust particle (IDP) showed that carbonates, not acid-insoluble organic compounds, were responsible for virtually all the absorption at 6.8 micrometers seen in the infrared spectra of this particle. The IDP examined had an infrared spectrum characteristic of layer-lattice silicates and belongs to a class of IDP's whose spectra resemble those of protostellar objects like W33 A, which also exhibit a band at 6.8 micrometers.     

Plutonium-244 fission tracks: evidence in a lunar rock 3.95 billion years old

Tracks attributed to the spontaneous fission of plutonium-244 and of uranium-238 were detected in a large whitlockite crystal in the lunar breccia 14321 from the Fra Mauro formation. For a track-retention age of 3.95 x 10(9) years the number of plutonium tracks relative to the number of uranium tracks is 0.51 +/- 0.15, provided that the rock was not heavily neutron-irradiated 3.95 X 10(9) years ago.     

Acceleration of argon ions to 1.17x1010 electron volts

Argon ions were accelerated to 1.17x10(10) electron volts in the Princeton Particle Accelerator. The synchrotron was tuned by use of a neon beam with a charge-to-mass ratio equal to that of the argon ions. The fully accelerated argon ions were detected by the observation of etched tracks in cellulose nitrate sheets and also by the use of scintillation counters. Predictions of the range and of the characteristics of argon tracks in plastics were confirmed.     

Cosmic-ray tracks in plastics: the apollo helmet dosimetry experiment

Counts of tracks from heavy cosmic-ray nuclei in helmets from Apollo missions 8 and 12 show variations caused by solar modulation of the galactic cosmic-ray flux. Specific estimates of the biological damage to certain nonreplaceable cells by track-forming particles during these space missions indicate that the fraction of deactivated cells could range from a lower limit of 3 x 10(-7) to an upper limit of 1.4 x 10(-4).     

Particle Track, X-ray, Thermal, and Mass Spectrometric Studies of Lunar Material

Particle tracks in Apollo 11 samples are dominantly of cosmic ray and solar origin: primary galactic and solar flare particles, likely spallation recoil tracks, and possible solar-wind heavy particles. The energy spectrum of irongroup nuclei is inferred from track density gradients in surface layers, and a limit of < 10(-7) centimeter per year is deduced for the surface erosion rate. From cosmic ray tracks in rock and core samples it is clear that the lunar soil is stirred often during each few million years. X-rays reveal augite, anorthite, olivine, ilmenite, troilite, nonmeteoritic iron, and assorted glasses, but no major structural damage. Hydrogen, helium, and other gases in the fines are compatible with expected solar wind ratios.     

Navigation of single homing pigeons: airplane observations by radio tracking

Navigation of homing pigeons was investigated by tracking their homeward flights from a light airplane. Released on successive days from a single training point 35 miles (56 kilometers) from home, individual pigeons, each carrying a transmitter, were repeatedly tracked back to theirloft. No two tracks covered the same ground for even short distances, yet all tracks were within 10 miles of a straight line. Results from further releases north and south of the training point suggest that pigeons often use three methods in sequence to find home: compass orientation, bi-coordinate navigation, and orientation by familiar landmarks.     

Optimized routing on agricultural fields by minimizing maneuvering and servicing time

Agricultural machines spend a significant part of their time on non-productive operations such as maneuvering near the boundaries of the field and loading or offloading of inputs or outputs (here referred to as servicing). This paper integrates existing methods for route optimization so as to minimize the time spent on turns and machine servicing on fields cultivated in straight rows. The following variables are optimized: (1) the orientation (angle) of the tracks, (2) the order of tracks, and (3) the types of turns between tracks. The angle of the tracks relative to field boundaries influences the number and lengths of the machine tracks, the number of turns and the positions where the machine can be serviced. Track order and the type of turns are selected to achieve overall efficiency. The algorithm was tested by computing routes for a set of fields of different sizes and assuming different operations. On small fields that do not require servicing, optimizing the turns between tracks resulted in a reduction of up to 50 % in turning time compared to the prevailing practice of navigation between adjacent tracks. A comparison of two sprayers in terms of servicing efficiency suggested that the algorithm can help selecting machinery for given field geometries. In some cases requiring machine servicing, the track orientation giving the shortest turning time did not produce the least servicing time. This illustrates that machine servicing should be taken into consideration for global optimization of machine traffic.     

Solar particle tracks in glass from the surveyor 3 spacecraft

A glass filter from Surveyor 3 has a surface density of approximately 1 x 10(6) tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 x 10(6) E(-2) [in particles per square centimeter per year per steradian per (million electron volts per nucleon)], where E is the energy and N is the number of particles, from 2 million electron volts per nucleon to approximately 7 million electron volts per nucleon and dN/dE = 1.17 x 10(7) E(-3) at higher energies. Not much difference is observed between 0.5 and 5 micrometers, an indication that there is a lack of track-registering particles below 0.5 million electron volts per nucleon. The Surveyor data are compatible with track results in lunar rocks, provided an erosion rate of approximately 10(-7) centimeter per year is assumed for the latter. The results also suggest a small-scale erosion process in lunar rocks.     

Extralunar dust in apollo cores?

Densities of nuclear tracks exceed 10(11) per square centimeter in several percent of the micrometer-size silicate grains from all depths in the 12-and 60-centimeter lunar cores. Either these grains were irradiated in space as extralunar dust or the ratio of iron to hydrogen in low-energy (about 1 million electron volts per nucleon) solar particles is orders of magnitude higher than in the photosphere.     

Gas-rich meteorites: possible evidence for origin on a regolith

The asymmetry of irradiation features of grains in the Kapoeta and Fayetteville meteorites suggests irradiation on a regolith before meteorite formation. Chondrules and broken grains require approximately 10(4) years of irradiation time between formation or fracturing and compaction into the meteorite. Shock erasure of tracks from irradiated Kapoeta feldspars requires a severe shock event during or after meteorite formation.     

Cosmic-ray record in solar system matter

The energetic nuclei in cosmic rays interact with meteoroids, the moon, planets, and other solar system matter. The nuclides and heavy nuclei tracks produced by the cosmic-ray particles in these targets contain a wealth of information about the history of the objects and temporal and spatial variations in the particle fluxes. Most lunar samples and meny meteorites have complex histories of cosmicray exposure from erosion, gardening, fragmentation, orbital changes, and other processes. There appear to be variations in the past fluxes of solar particles, and possibly also galactic cosmic rays, on time scales of 10(4) to 10(7) years.     

Spot-application of fungicide for wild blueberry using an automated prototype variable rate sprayer

Wild blueberry producers apply fungicide uniformly without considering significant bare spots in the field. The wrong or over use of fungicide in bare spots results in an increased cost of production and threatens the environment. An automated prototype variable rate (VR) sprayer was used for spot-application (SA) of Chlorothalonil (Bravo^®) fungicide in a wild blueberry field. Eighteen 6.1 m wide test tracks were selected in the field and bare spots were mapped using a real-time kinematics-global positioning system (RTK-GPS). Six plots were selected randomly for three different application rates. Water sensitive papers (WSP) were placed in foliage and bare spots in SA and uniform-application (UA) tracks. The percent area coverage (PAC) of WSP with both SA and UA in foliage and bare spot areas were calculated. Plant growth parameters were measured from all 108 randomly selected plots in SA, UA and control (CN) tracks for comparison. Plant images were taken over six selected plots in each of the 18 tracks. Images were analyzed using custom developed software to calculate the percentage of green pixels (PGP) for determining the effect of Bravo^® on plant health. Fruit yield parameters were also measured from selected plots for comparison. Non-significance of the t test for SA versus UA plant targets’ PAC indicated that there was no significant bias in the SA with saving (9.90–51.22 %) and SA was accurate. Bravo^® did not show any significant difference on plant growth parameters among SA, UA and CN. However, PGP, floral bud and harvestable yield of SA and UA were significantly increased over CN. Therefore, a VR sprayer could be used for SA of fungicides in wild blueberry cropping system to reduce chemical usage and maintain crop productivity.     

Swimming ability of carnivorous dinosaurs

Dinosaur tracks from Lower Jurassic rocks at Rocky Hill, Connecticut, were apparently made by a floating or half-submerged animal that was pushing along the bottom with the tips of its toes. These tracks were probably made by large carnivorous dinosaurs (Theropoda) and are apparently the first evidence of swimming by such animals.     

Olivines: revelation of tracks of charged particles

A one-step, three-component aqueous etchant was developed for revealing the tracks of charged particles in olivine. The etchant reveals tracks of small cone angle, which are equally well developed in all the crystallographic directions. The scope of fossil cosmic-ray track studies in extraterrestrial samples has thus been increased, because olivine is often an abundant constituent and because it has a higher threshold ionization for track registration and has lower uranium, thorium, and trace element concentrations as compared with pyroxenes and feldspars. The etchant does not attack any of the principal rock-forming minerals in normal etching time, which allows a nondestructive study of fossil tracks in thin-section mounts. The study of fossil cosmic-ray tracks in olivine is particularly valuable for investigations of very, very heavy cosmic-ray nuclei and for highly irradiated samples such as those found in the lunar regolith.     

Direct and remote sensing observations of the effects of ships on clouds

Under certain conditions ships can affect the structure of shallow layer clouds. Simultaneous observations of two ship track signatures in stratus clouds from a satellite and in situ from an aircraft show that in the ship tracks the droplet sizes were reduced and total concentrations of both droplets and particles were substantially increased from those in adjacent clouds. In situ measurements of the upwelling radiance within the ship tracks was significantly enhanced at visible wavelengths, whereas radiance at 2.2 micrometers was significantly reduced. Cloud reflectivity along the tracks was enhanced at 0.63 and 3.7 micrometers. These observations support the contention that ship track signatures in clouds are produced primarily by particles emitted from ships.     

Intervacuole exchange in the yeast zygote: a new pathway in organelle communication

A new pathway of vesicle traffic between organelles has been identified. The vacuoles (lysosomes) of Saccharomyces cerevisiae zygotes rapidly exchange their contents at a specific point in the cell cycle. With the use of fluorescence microscopy, "tracks" were observed that connect the original parental vacuoles to the newly forming bud vacuoles. These observations suggest that vacuole-derived vesicles rapidly move along the tracks in both directions, equilibrating vacuole contents. This rapid vesicle movement may be responsible for vacuole formation in newly developing cells.     

Particle track enhancement in cellulose nitrate by application of an electric field

The number and length of etchable tracks, created by alpha particles in a cellulose nitrate sheet, are significantly enhanced by the application of an electric field across the cellulose nitrate.     

Very heavy solar cosmic rays: energy spectrum and implications for lunar erosion

The energy spectrum of solar cosmic-ray particles of the iron group has been determined for the first time over the energy range from 1 to 100 million electron volts per nucleon by the use of glass removed from the Surveyor 3 spacecraft. The difference between the observed (energy)(-3) spectrum and the limiting spectrum derived previously from tracks in lunar rocks gives an erosion rate of 0 to 2 angstroms per year. High-energy fission of lead, induced by galactic cosmicray protons and alpha particles, has also been observed.     

A model to analyze as-applied reports from variable rate applications

During variable rate operations, controller systems report information (as-applied files) about desired rates and real applied rates on georeferenced points along the machine tracks. These reports are useful for operation quality control but they have not been widely used to their potential. The goal of this study was to create a model to help analyzing as-applied files based on quantifying and locating off-rate errors and their probable related sources. The model calculates off-rate error at every point and classifies them as less than target rate, acceptable or over the target rate. Possible error sources are classified regarding three aspects: vehicle path position (inward, middle or outward), high rate change (step up or down) and vehicle acceleration or deceleration. A pulled type applicator (application 1) and a self-propelled applicator (application 2) were analyzed. An average of 30.6 % of the recorded points was considered application errors (10 % off the target rate). 70.5 % of them occurred on high rate change points on application 1 and 69.7 % on acceleration/deceleration points on application 2. The self-propelled applicator performed better during high transition rate than the pulled type which performed poorly when transition rate exceeded 10 %. The model determined the major and minor factors related to application error. It provided means to assess equipment limitations and its impact over the quality of application. The trials demonstrated its flexibility and how it can improve the use of as-applied files.     

Particle track identification: application of a new technique to apollo helmets

The Apollo helmets are being used to record the dose of heavy particles to which astronauts are exposed on space missions. An improved method for examining and identifying the etched tracks of heavy charged particles consists of replicating tracks and measuring the etching rate as a function of position along the track. Tracks have been observed in Apollo helmets that correspond to ionized atoms heavier than iron.