Showing papers by "United States Department of the Army published in 1976"

Retinal sensitivity to damage from short wavelength light

Abstract: A GROWING body of literature attests to the deleterious effects of long term exposure to light1–8. To define more critically the differences between thermal and photochemical effects, we have exposed the retinae of rhesus monkeys to eight monochromatic laser lines from 1,064–441.6 nm. Thermal damage to the retina is to be expected for the 1,064-nm line since the photopigments are not involved and energy absorption takes place predominantly in the melanin granules of the pigment epithelium and the choroid. Although data on pathogenesis are not yet available, we found some interesting differences in retinal sensitivity in going from the near infrared to the blue wavelengths in the visible spectrum.

Dynamic Stall Experiments on Oscillating Airfoils

Abstract: Dynamic stall and unsteady boundary layer separation have been studied in incompressible flow at moderately large Reynolds numbers. By varying the leading-edge geometry of an NACA 0012 airfoil, three different types of stall were produced. For most of the configurations studied, including the basic NACA 0012 profile, dynamic stall was found not to originate with the bursting of a leading-edge laminar separation bubble, as is commonly believed. Instead, the vortex shedding phenomenon, which is the predominant feature of dynamic stall, appears to be fed its vorticity by the breakdown of the turbulent boundary layer.

Prices and Demands for Input Characteristics

Abstract: Price of an input equals the sum of the money values of the input's characteristics to the purchaser; money value of each of an input's characteristics equals the input's yield of the characteristic multiplied by the money value of one unit of the characteristic. Demand for an input is affected by the input's characteristics. The themes are derived from a neoclassical firm model, in which the arguments of the firm's production function are quantities of input characteristics used, and from duals of linear programming blending problems. These themes are used to evaluate corn grades.

Generating Bessel functions in Mie scattering calculations using continued fractions

Abstract: A new method of generating the Bessel functions and ratios of Bessel functions necessary for Mie calculations is presented. Accuracy is improved while eliminating the need for extended precision word lengths or large storage capability. The algorithm uses a new technique of evaluating continued fractions that starts at the beginning rather than the tail and has a built-in error check. The continued fraction representations for both spherical Bessel functions and ratios of Bessel functions of consecutive order are presented.

Thermoelectric voltage generator

Abstract: A thermoelectric voltage generator utilizing heat from a vehicle exhaust torovide a differential temperature through a plurality of thermoelectric elements comprised of serially connected alternate N- and P-type semiconductors having alternate electrical contacts between adjacent elements at a hot side and at a cold side to produce electrical energy in accordance with the Seebeck effect and in which the electrical energy is applied to an external device by way of connections at opposite ends of said plurality of thermoelectric elements.

Minimum Unit Stream Power and Fluvial Hydraulics

Abstract: Fluvial hydraulics is complex because the velocity, slope, depth, and channel roughness are all subject to change. The unit stream power, defined as the rate of potential energy expenditure per unit weight of water, required to transport a given sediment load is sensitive to water depth when the sediment concentration is low. The interdependence between unit stream power and water depth decreases as sediment concentration increases. A computer program is used to generate different combinations of velocity, slope, depth, and unit stream power for a given sediment load. The generated unit stream power in the lower flow regime either has a clear minimum value at a particular depth or approaches a minimum value for a given sediment load. These agreements suggest that an alluvial channel in the lower flow regime adjusts its velocity, slope, depth, and roughness in such a manner that a given sediment load can be transported with the minimum amount of unit stream power.

UV/Ozone Cleaning of Surfaces

Abstract: The ultraviolet (UV)/ozone cleaning procedure is shown to be an effective method of rapidly removing a variety of contaminants from surfaces. It is a simple-to-use dry process which is inexpensive to set up and operate. It can produce · clean surfaces in air, at ambient temperatures. The experiments were performed on quartz and metal surfaces. The contaminants which were successfully removed include oils and greases (including silicones), fluxes, skin oils, and contamination adsorbed during prolonged exposure to air. The experiments were aimed at defining the variables and determining the optimum conditions for producing clean surfaces by UV irradiation. The important variables are: the contaminants initially present, the precleaning procedure, the wavelengths emitted by the UV source, the atmosphere between the source and sample, the distance between the source and' sample, and the time of exposure. For surfaces which are properly precleaned and placed within a few millimeters of an ozone-producing UV source, the process can consistently produce a clean surface in less than 1 rain. Experiments performed with two low-pressure mercury discharge UV sources, one which generates ozone and one which does not, indicate that the combination of short-wave UV light plus ozone produces a clean surface substantially faster than either short-wave UV light without ozone or ozone without UV light.

Scrub typhus: a common cause of illness in indigenous populations

Abstract: An explanation was sought for the disparity between the low reported incidence of scrub typhus and the high prevalence of antibody to Rickettsia tsutsugamushi in the rural population of Malaysia. A combination of isolation of the organism, titration of antibody by indirect immunofluorescence, and the Weil-Felix test was used to confirm infections. Scrub typhus was found to be very common, causing 23% of all febrile illnesses at one hospital. The infection was particularly prevalent in oil-palm workers, causing an estimated 400 cases annually in a population of 10,000 people living on one plantation. The clinical syndrome, whether mild or severe, was difficult to distinguish from that due to other infections. Eschars, rashes and adenopathy were uncommon. When used to examine early sera, the Weil-Felix test failed to confirm the diagnosis in most infections.

Delineation and analysis of clusters in orientation data

Abstract: This paper presents a technique for (1) clustering orientation data with minimum constraint on resulting partitions, and (2) testing clusters against a probability distribution defined on the unit sphere which admits elliptical symmetry about its mean. The use of an objective function to highlight certain features of the data is discussed. The technique for delineation and analysis of clusters is applied to an example problem through use of a computer code.

Hypertriglyceridemia Produced by Endotoxin: Role of Impaired Triglyceride Disposal Mechanisms

Abstract: The role of Salmonella typhimurium endotoxin in producing hypertriglyceridemia was investigated in 70 male rhesus monkeys. Dose-response studies were performed with 0.3-9.0 mg of endotoxin/kg injected intravenously; free fatty acids and triglycerides were measured during the subsequent 8 hr. The effect of endotoxin on lipid disposal mechanisms was assessed by both intravenous lipid-loading tests and total plasma lipolytic activity after administration of heparin. The possible interference of endotoxin with lipid-clearing enzymes was also explored. Smaller doses of endotoxin (0.3 and 0.9 mg/kg) produced significant increments in free fatty acids within 2-5 hr of administration, with minimal trilgyceride increments. Larger doses of endotoxin (2.8-9.0 mg/kg) failed to produce significant elevations in free fatty acids but did result in significant triglyceride increases 2-6 hr after administration. Within 4 hr after administration of 7 mg of endotoxin/kg, both tests showed impaired disposal of lipids. However, once lipid-clearing enzymes were activated, endotoxin did not reduce lipolytic activity in vitro. These results support the contention that endotoxin significantly elevates serum triglyceride concentrations and leads to impaired lipid disposal mechanisms by interfering with the activation of lipid-clearing enzymes.

Light Scattering by Irregular Randomly Oriented Particles

Abstract: A method for calculating light scattering by irregular randomly oriented particles yields results that are in good agreement with experimental data. The method is based on the assumption that surface waves are present in scattering by spherical particles, but they are absent in scattering by irregular particles.

Post-Pleistocene history of the United States inner continental shelf: Significance to origin of barrier islands

Abstract: Segments of the U.S. Atlantic coast differ markedly in shoreline and shelf configuration because of both geologic setting and Quaternary geologic history. Regional trends in shelf structure, sediment sources, and history correlate with regional trends in adjacent shoreline configuration, and the Holocene transgressive history of the shelf has a direct bearing on the evolution of the present coastline. The shelf sedimentary record, particularly in the mid-Atlantic region, contains substantive evidence that precursors to existing barrier islands were common in Holocene time. Nearshore linear shoals are associated with barrier-island coastlines, and their continuity in position on the shelf, coupled with the presence of an underlying lagoonal substrate, implies persistent retreat of a barrier coastline during sea-level rise. Retreat paths of shoals off large capes and estuaries similarly indicate a consistency in shoreline type and orientation through time. Collectively, this information strongly suggests that barrier islands of the U.S. Atlantic coast originated far out on the shelf, and it invalidates certain criteria (coastal linearity, lithology of sediments beneath the modern lagoon) formerly cited as evidence for mode of formation. Understanding how and the processes by which barriers evolved relate directly to present and future behavior of barriers. Sediments eroded from the foreshore and shoreface are transported both along the coast and landward, aggrading as nearshore shoals, spits, tidal deltas, dunes, and overwash fans. Barrier islands lengthen both by sand accumulation (spit extension) and by submergence (deepening and headward extension of the lagoon). Development of barrier islands is influenced by rate of sea-level advance and sediment supply. Once initiated, barrier islands lengthen and retrograde through a combination of processes, including spit elongation, overwash, and flooding of back barrier lagoons.

Odor intensity and pleasantness for a diverse set of odorants

Abstract: Data Analysis Office, U.S. Army Natick Laboratories, Natick, Massachusetts 01760 Observers compared the odor of butanol to the odors of various concentrations of 32 chemicals, and also rated the odor pleasantness and unpleasantness of these 32 odorants by a line matching procedure. All stimuli were presented to the observers by air dilution olfactometers. Odor intensity matches between each odorant and butanol were often describable by power functions. A derived magnitude estimate of odor intensity was obtained through a calibration of the butanol concentration scale. Most odorants grew less rapidly in intensity than butanol, and all odorants grew in intensity as decelerating functions of concentration. A more general function of the form P =: k1 + k2Ck3 was needed to account for the pleasantness-unpleasantness judgments. In this study, most odorants were rated either neutral or unpleasant. Observers showed far more variability in hedonic judgments than in intensity judgments.

Can a Black "culture assimilator" increase racial understanding?

Abstract: A programmed instruction approach to race relations training in the United States Army involved the development of the technique (culture assimilator) and its field test In the development phase 65 black officers, 90 black enlisted men, 65 white officers, and 90 white enlisted men participated; in the field test 84 white junior grade officers and 85 black junior grade officers participated Results indicated: (a) the sample of problems used in the assimilator represents a set of events far more familiar to black officers than the white officers; (b) blacks obtain higher scores on the assimilator (indicative of greater knowledge of the black perspective on race relations in the army) than whites; (c) significant evidence of learning of acculturative materials on the part of white officers was obtained; and (d) there was significant improvement on an independent test of intercultural understanding

The effect of bacterial infections on ketone concentrations in rat liver and blood and on free fatty acid concentrations in rat blood.

Abstract: The concentrations of cytoplasmic lactate and pyruvate and the NAD+/NADH ratio and the concentrations of mitochondrial acetoacetate, beta-hydroxybutyrate, and the NAD+/NADH ratio were determined in normal, fed, and fasted rats, and in rats infected with Streptococcus pneumoniae, Francisella tularensis, and Salmonella typhimurium. The various infections were found to have little or no effect on the cytoplasmic parameters. In normal rats, fasting caused a marked increase in blood and hepatic ketone concentration and in serum free fatty acid content. Fasted infected rats, however, did not show the increase in ketone bodies or serum free fatty acids normally associated with fasting alone. The mitochondrial NAD+/NADH ratio increased as the infections progressed, reversing the normal trend. The introduction of an infection during the fasting state when ketone bodies and serum free fatty acids were elevated caused a marked depression in their concentration. These data have led to a postulation of decreased lipolysis in the infected host to account for the lowered hepatic and blood ketone bodies and the decreased level of serum free fatty acids.

High dynamic range receiver front end mixer requiring low local oscillator injection power

Abstract: An improved circuit utilized in an RF tuner or receiver for selecting and nverting an RF signal to an intermediate frequency with reduced injection power requirements.The circuit is utilized in the "front end" of a radio frequency receiver or tuning section, the purpose being to convert the received RF signal to an intermediate frequency. The improved circuit comprises and includes a diode sampling bridge coupled to an RF signal receiving source, such as an antenna, a local oscillator coupled across the bridge providing pulses for actuating and turning on particular diodes of the bridge for a relatively short length of time. The bridge output is coupled to a selecting transistor, which may include a crystal filter coupled to the emitter of the transistor. The pulsing signal across the diode bridge is relatively short in comparison with the received RF signal. When the diode sampling bridge is conducting, the RF signal is mixed and passed to the selecting transistor base. The selecting transistor, with its emitter coupled to the crystal filter, amplifies only a signal of a desired frequency. The short pulse actuation in the front end for mixing requires less injection power, allowing the circuit to be adapted for use with battery powered equipment.

Defective lipid disposal mechanisms during bacterial infection in rhesus monkeys.

Abstract: Mechanisms producing hypertriglyceridemia during bacterial sepsis have not been well defined. In this study lipid disposal mechanisms were assessed in 76 infected and 19 control male rhesus monkeys by the ability to dispose of triglycerides after: (1) oral lipid loading; (2) intravenous lipid loading; and (3) by lipolytic enzyme activity tests as measured by postheparin lipolytic activity (PHLA). Studies were performed both before and 48 hr after intravenous inoculation with either Salmonella typhimurium or Diplococcus pneumoniae when illness was uniformly severe and fasting serum triglyceride elevations were increased maximally. S. typhimurium -infected monkeys demonstrated significant fasting hypertriglyceridemia ( p D. pneumoniae sepsis, average fasting triglyceride concentrations were slightly, but not significantly elevated. While oral lipid clearance was impaired, intravenous lipid clearance was unimpaired, and PHLA was slightly reduced. Marked lethargy, agitation, and a 20% mortality were present during this gram-positive infection. Results of this study support the concept that an impairment of lipid disposal mechanisms, particularly during gram-negative sepsis with S. typhimurium , may significantly contribute to the observed hypertriglyceridemia.

Phase lock loop multitone interference canceling system

Abstract: An interference canceling system in which a phase lock loop is utilized as narrow band tracking filter to adaptively lock to interference tones to be canceled by a process of signal subtraction.

Cyclic Triaxial Strength of Standard Test Sand

Abstract: A cooperative cyclic triaxial strength test program was performed by eight university, government, and consulting laboratories to define the cyclic strength characteristics often called the liquefaction potential or cyclic mobility of a standard test sand. Other laboratories may check the adequacy of their cyclic triaxial test equipment and testing procedures by duplicating the results of these tests. It was found that a good degree of agreement for cyclic soil strength values could only be achieved among different laboratories when proper attention was given to the following testing details: (1) Great care must be taken in measuring specimen dimensions and weight to accurately calculate specimen dry weight; (2) tested specimen dry weights must be within 0.5 pcf (8 kg/m²) of the specified value; (3) specimen preparation techniques must not deviate from the specified method; and (4) a smooth periodic loading wave form, such as a sine wave, should be used for testing.

Fuel cell-secondary cell combination

Abstract: A hybrid fuel cell secondary battery system suitable for low power sensor plications is provided. The system comprises in combination, a fuel cell, a fully contained fuel and oxidant source for the fuel cell, a DC to DC power processor for boosting the voltage output from the fuel cell, and a nickel-cadmium battery in parallel with the output from the DC to DC processor to sustain peak power drains.

Incidence and Levels of Bacillus cereus in Processed Spices

Abstract: Spices purchased by the Army, Navy, Marines, and Air Force were tested for incidence and levels of Bacillus cereus. One hundred and ten processed spices, including bay leaves, red pepper, chili powder, cinnamon, garlic powder, mustard powder, and oregano were tested. Bacillus cereus was found in 53% of the spices and counts ranged from 50 to 8500 per gram. Eighty-nine percent (88/99) of the isolates tested were toxigenic in rabbits, by the vascular permeability assay, and toxigenic B. cereus was found in each kind of spice. These data have significant implications for food safety and sanitation and for fumigation of spices by gas, or irradiation.

Speckle noise in displays

Abstract: A theory is presented which relates the minimum detectable contrast level for an object in the presence of noise to the statistics of the speckle. Consideration is given to smoothing of the noise by multiple looks and by area. Measurements of the minimum detectable contrast are made for two types of speckle noise. First, a coherent, plane wave is added to an ideal diffuse wave and the threshold of detection is established as a function of the beam ratio. Secondly, these results are compared to the technique of speckle smoothing using an N-fold intensity superposition of fully developed speckle pattens. Good agreement of experiments with theory is observed.