Showing papers by "Brigham Young University published in 1974"

The planetary magnetic field and magnetosphere of Jupiter: Pioneer 10

Abstract: Data obtained by the Pioneer 10 vector helium magnetometer are presented along with models of the intrinsic magnetic field of Jupiter and its magnetosphere. Data acquired between 2.84 and 6.0 Jupiter radii, where the intensity of the planetary field ranged between 1900 and 18,400 gamma, were used to develop a six-parameter eccentric dipole model of the field. The dipole so derived has a moment of 4.0 G (R sub J) cubed and a tilt angle with respect to Jupiter's rotation axis of 11 deg. A model of the Jovian magnetosphere is presented in which the essential feature is an eastward current sheet that forms an annulus with Jupiter at the center. At large distances from the planet the current sheet is nearly parallel to Jupiter's equator but, in general, does not lie in it. The current sheet is warped, so that it is above the equator on one side and below it on the other. The current sheet rotates with the planet, more or less like a rigid body, this behavior causes an apparent up and down motion and periodic crossings of the current sheet by Pioneer.

Magnetism and the interior of the Moon

Abstract: The application of lunar magnetic field measurements to the study of properties of the lunar crust and deep interior is reviewed. Following a brief description of lunar magnetometers and the lunar magnetic environment, measurements of lunar remanent fields and their interaction with the solar plasma are discussed. The magnetization induction mode is considered with reference to lunar magnetic permeability and iron abundance calculations. Finally, electrical conductivity and temperature calculations from analyses of poloidal induction, for data taken in both the solar wind and in the geomagnetic tail, are reviewed.

Magnetic field of Jupiter and its interaction with the solar wind

Abstract: Jupiter's magnetic field and its interaction with the magnetized solar wind were observed with the Pioneer 10 vector helium magnetometer. The magnetic dipole is directed opposite to that of the earth with a moment of 4.0 gauss R_J^3 (R_J, Jupiter radius), and an inclination of 15° lying in a system III meridian of 230°. The dipole is offset about 0.1 R_J north of the equatorial plane and about 0.2 R_J toward longitude 170°. There is severe stretching of the planetary field parallel to the equator throughout the outer magnetosphere, accompanied by a systematic departure from meridian planes. The field configuration implies substantial plasma effects inside the magnetosphere, such as thermal pressure, centrifugal forces, and differential rotation. As at the earth, the outer boundary is thin, nor diffuse, and there is a detached bow shock.

Late Cenozoic Alkalic Basaltic Magmas in the Western Colorado Plateaus and the Basin and Range Transition Zone, U.S.A., and Their Bearing on Mantle Dynamics

Abstract: Late Cenozoic volcanism along the eastern margin of the Basin and Range province in northern Arizona and Utah has created a suite of essentially alkalic basaltic lavas similar to those occurring in other regions of recent uplift, extensional tectonism, and high heat flow. The lavas were derived from a series of partial melts of the mantle, modified to varying degrees by polybaric fractionation of olivine and possibly plagioclase and clinopyroxene during ascent to the surface. Basanite and alkali olivine basalt melts originated at depths of at least 65 km and possibly as much as 95 km (20 to 30 kb) by variable but generally small degrees of partial melting. More voluminous hawaiite magmas originated at shallower depths by a somewhat greater degree of partial melting and were more substantially modified by crystal fractionation prior to extrusion. Magmas parental to the lava extrusions became increasingly divergent in composition with time, reflecting a broadening depth interval of partial melting in the mantle. Concurrent eruptive activity and block faulting generally shifted eastward with time at a rate of approximately 1 cm/yr. These time-space-composition variations, in combination with the observed essentially marginal localization of basaltic volcanism for the whole Basin and Range province, are explained in terms of upper mantle dynamics. We envisage upwelling mantle or plume activity beginning sometime in the middle to late Cenozoic in the core area of the Basin and Range province and causing progressive thinning or “erosion” of the lithosphere. Erosion ultimately produced a steep, keellike asthenosphere-lithosphere boundary beneath the Colorado Plateaus and the Basin and Range transition zone. Eastward-flowing mantle peridotite from the core of the plume was throttled against this keel, causing localized shear heating. This heat enhanced partial melting so that sufficient liquid was created to separate from the refractory residuum and to rise to the surface. Diapiric uprise of magma, or partially melted mantle in the uppermost mantle, or injection of a swarm of dikes into the lower crust, might have weakened and attenuated the overlying brittle crust, causing concurrent faulting. Eastward erosion of the keel and site of partial melting as time progressed allowed eruptive and fault activity to also migrate.

Interrelationship between serum beta-lysin, lysozyme, and the antibody-complement system in killing Escherichia coli.

Abstract: The effects of different serum components alone and in conjunction with each other on Escherichia coli B were investigated. In general, the viability, turbidity, and electron microscope results were compatible with the following conclusions. The most efficient killing and destruction of E. coli B occurred when beta-lysin, lysozyme, and the antibody-complement system functioned in cooperation with each other at the serum concentration in isotonic solutions. The addition of sucrose protected the bacteria from the lethal and lytic action of these agents. Elimination of lysozyme from serum had the least effect on bactericidal activity, even though lysozyme treatment caused the cell wall to separate from the cytoplasmic membrane and caused clear areas to appear in the inner granular layer of the cell wall. Beta-lysin removal had an intermediate effect on the serum bactericidal activity. Beta-lysin treatment caused cell walls to collapse, allowed cytoplasmic contents to leak out of the cells, and stopped the separation of cell wall and cytoplasmic membrane, which normally takes place in 0.5 M sucrose solution. Inactivation of the complement eliminated the serum bactericidal activity against E. coli B. After treatment with antibody and complement, the cell walls became thick and indistinct, a portion of the cytoplasmic contents escaped, and patches of the middle layer of the cell wall appeared in freeze-etch preparations. Beta-lysin damaged the cytoplasmic membrane, lysozyme damaged the inner peptidoglycan layer of the cell wall, and the antibody-complement system damaged both the middle lipopolysaccharide layer of the cell wall and the cytoplasmic membrane.

Protein composition of spinach chloroplasts and their photosystem i and photosystem ii subfragments

Abstract: — The proteins of spinach chloroplasts and their subfragments containing photosystem I and photosystem II, obtained by Triton X-100 treatment or French-pressure rupture, were separated by sodium dodecyl sulfate (SDS)-acrylamide electrophoresis at pH 7·0 in phosphate buffer. The individual protein bands were identified where possible by comparing them with known, isolated and characterized proteins from chloroplasts, and their molecular weights were determined. The protein composition of the chloroplast fragments were correlated to the functional properties of these fragments. Distinct patterns were obtained for photosystem I and photosystem II particles. The major protein of photosystem II is expressed in the 23 kilodalton range and photosystem I proteins seem to be clustered mainly in the 50–70 kilodalton range.

Effects of a competitive endurance training program on self-concept and peer approval.

Abstract: Summary The purpose of this study was to investigate the effects of a cardiovascular fitness program on the self-concept and peer approval of seventh grade boys. Thirty-seven low self-esteem Ss were randomly divided into a control group (participated in no formal physical education activity) and an experimental group (participated in a special running training program). At the end of an 18 week training program the two groups were significantly different in cardiovascular endurance, indicating the efficacy of the experimental treatment. There was an increase in self-concept from pretest to posttest for the experimental group only. Neither group had a significant change in peer approval.

Conservatism, Racial Intolerance, and Attitudes toward Racial Assimilation Among Whites and American Indians

Abstract: Summary Among samples of adult whites and American Indians in Seattle conservatism as measured by the Wilson-Patterson scale was inversely related to educational attainment, directly related to age, somewhat more evident among females than males, and not related to income. Factor analysis revealed four readily interpretable dimensions of conservatism among the whites (family and motherhood, religious factor, racial factor, and radical counterculture factor), but only two clearly interpretable factors among the Indians (religious factor, radical counterculture factor). The anticipated greater conservatism of the Indians did not appear; their cumulative conservatism scores were comparable to those of whites. The correlation between conservatism and support for Indian assimilation was positive, and stronger for whites than for Indians. There was a racial difference in the relation between conservatism and racial intolerance; among whites the conservatives were most likely to give intolerant responses about I...

Effect of thiamine deprivation and thiamine antagonists on the level of gamma-aminobutyric acid and on 2-oxoglutarate metabolism in rat brain.

Abstract: Brain levels of y-aminobutyric acid (GABA), glutamate and 2-oxoglutarate, activities of glutamate decarboxylase GABA-transaminase plus succinic semiaidehyde dehydrogenase and blood levels of glutamate and 2-oxoglutarate were determined in normal, thiamine-deprived, oxythiamine-treated and pyrithiamine-treated rats. Brain GABA levels were significantly reduced in thiamine-deprived and pyrithiamine-treated rats, but the activities of the enzymes of the GABA shunt pathway were not affected. Brain levels of glutamate were decreased and of 2-oxoglutarate increased in all three types of deficiency. This was associated with similar decreases in glutamate and increases in 2-oxoglutarate in the blood in all three deficient groups. Intraventricular injections of 2-[U-14C] oxoglutarate into the brain in these four groups of rats resulted in some significant differences in distribution of 14C in various TCA-pathway intermediates and satellite compounds in the brain. Increases in 14C-label were observed for glutamine and 2-oxoglutarate in all three deficient groups as compared to controls. The 14C content of succinate, fumarate and aspartate was decreased in the thiamine deprived and PTh-treated groups and [14C]glutamate was decreased in all three deficient groups. The 14C content of GABA was not significantly affected.

Social Origins of American Scientists and Scholars

Abstract: Data from a wide variety of sources reflect geographical, baccalaureate, and social class variations in the production of scientific and scholarly doctorates in the United States. To a significant extent, these variations are associated with the kind of religiousethnic group from which such persons come. Roman Catholics are extremely low producers of scientists and scholars, but fundamentalistic and traditional Protestant faiths (southern white Protestants, Lutherans) are also low producers. Liberal Protestant sects, such as Unitarians and Quakers, and secularized Jewish groups are highly productive, and less liberal faiths are moderately productive. Variations in productivity are reflective of differences in beliefs and values. Highly productive groups share a certain set of values, unproductive groups hold the antithesis of these, and those groups intermediate in productivity possess a mixed blend. Tentatively, the common beliefs and value systems of high producers seem to include naturalism; intrinsic valuation of learning and the individual quest for truth; emphasis on human dignity, goodness, and competence; a life pathway of serious dedication, of service to humanity, of continual striving; humanistic equalitarianism; a pragmatic search for better ways of doing things unfettered by traditional restraints; and a focus on the relatively immediate, foreseeable future which can be affected by personal effort. Historically, the scientists (or their immediate ancestors) have broken away from the traditional orthodoxy, broadened certain values, and retained others. For example, the children of Jewish immigrants to the United States departed from the traditional ritualism of the eastern European Jewish community, broadened the old value of scriptural erudition to include secular learning of all kinds, but maintained emphasis upon personal striving and social responsibility. Also, it appears that eminent scientists often emerge from devout Protestant homes emphasizing learning and responsibility but that such scientists frequently depart from the parental religious faith (31) . Psychodynamically, this set of cultural values produces a person with an inquiring cognitive disposition, whose duty it is to strive diligently to improve the human condition. Given a certain level of intellectual talent, and cultural support in educational, scientific, and scholarly institutions, youth will frequently choose careers in scientific and scholarly professions. This same cultural milieu apparently also produces disproportionate numbers of inventors and entrepreneurs; historically, it produced those who activated the industrial revolution and those who generally were responsible for rapid economic growth. The data discussed herein extend only to about 1960, prior to the great social unrest of the 19609s and early 19709s. Speculatively, one might predict that productivity will diminish to the extent that current social movements stressing existential futility, goal attainment "now," or power relationships are successful in penetrating groups which have been highly productive, since these emphases undermine longterm scholarly striving.

Effect of pharmacologically-induced arousal on the evoked potential in the unanesthetized rat.

Abstract: Three positive-negative wave complexes of the visually evoked response (VER) in the unanesthetized rat were examined following iterative photic stimulation. EEG activation was induced by physostigmine, amphetamine, or pilocarpine in order to compare the peak latency and amplitude values of the VER components during arousal. It was served that the peak latency of only one component, a late negative wave occurring at approximately 160 msec was affected by the drug treatments. Except for one negative-positive amplitude measure occurring between 70 and 90 msec, the effect of drug-induced activation was to suppress the amplitude excursion of the remaining wave components. These observations agree with other VER studies in which arousal level was modified by type of behavioral task. It is suggested that the late negative wave peaking at 160 msec comprised the first wave of a photically evoked after-discharge burst.

Mica Granites of the Kern Mountains Pluton, Eastern White Pine County, Nevada: Remobilized Basement of the Cordilleran Miogeosyncline?

Abstract: Among the many granitic plutons within the Basin and Range province of western North America, those in the Kern Mountains of eastern Nevada and western Utah are unusual structurally, mineralogically, and chemically. The two largest intrusions, which together are exposed over an area of 130 sq km (51 sq mi), have well-defined border facies of leucocratic and generally aplitic rocks, or of protoclastic rock developed from coarser core-facies material. Within the core facies are abundant aplitic, leucocratic dikes. The core facies of the larger intrusion (Tungstonia Granite) is a two-mica granite with conspicuous phenocrystic books of muscovite up to 5 cm across. The smaller intrusion (Skinner Canyon Granite) lacks muscovite, and Fe-Ti oxides and sphene are constant accessory phases in it. Rb-Sr and K-Ar isotopic analyses suggest a wide range of initial Sr 87 /Sr 86 ratios, which for the most part are unusually high—to nearly 0.7246 for the Tungstonia Granite—and a complex, protracted period of magmatism and isotopic adjustment that extended from possibly Mesozoic into mid-Cenozoic time. The simplest interpretation is that the final emplacement of the Tungstonia body occurred 60 m.y. ago and that the Skinner Canyon intrusion occurred between 30 and 45 m.y. ago. The data prompt the conclusion that the magmas represent remobilized sialic basement whose model dates (assuming an initial ratio typical for mantle-derived magmas) are in excess of 1.5 b.y. The occurrence of such anatectic intrusions within the relatively intensely metamorphosed parts of the infrastructure of the Sevier orogenic belt, rather than elsewhere in the Basin and Range province, is not unexpected, and it possibly represents a more advanced evolutionary stage than do the gneiss domes previously documented within this same belt.

Laminar-Turbulent Transition in Flow of Pseudoplastic Fluids with Yield Stresses

Abstract: An analysis of the laminar-turbulent transition behavior of power law non-Newtonian fluids with yield stresses reveals that considerable interaction occurs between the characterizing parameters m and Hedstrom number for low power law indexes, m. In particular, for m < 0.4 small yield stresses tend to destabilize the flow whereas large ones stabilize it. The results of this analysis suggest that in order to obtain correct predictions and interpretations of transitional and turbulent flows of nonNewtonian fluids, a correct modeling of the viscous rheological behavior of the fluid is essential. Nomenclature A = a dimensionless parameter defined by Eq. (6) D - pipe diameter / = friction factor He - Hedstrom number, defined by Eq. (17) K = laminar-turbulent transition parameter K = maximum value of K m = power law index in rheological model Re - Reynolds number,.defined by Eq. (8) r = radial coordinate u = v/(u}, dimensionless velocity v = velocity (v} ~ mean velocity T = -du/d£ j] = consistency index in rheological model k = r/rw £ = value of £ where K = K £o = TQ/TW p — fluid density a = dimensionless parameter defined by Eq. (7) r = shear stress TO = yield stress in rheological model

Adolescent Perceptions of Conjugal Power

Abstract: This study examines the accuracy of adolescent perceptions of conjugal power and the association of occupation, education, and female employment with these perceptions using data from two existing surveys. The parent with whom the adolescent identified most closely was perceived as relatively more powerful. Although perception of conjugal power varied somewhat by age and sex of adolescent, the data suggest that conjugal power may also vary by certain structural dimensions in the family, including age and sex of children. Furthermore, these age and sex differences did not affect the association of power with other variables. These findings imply that adolescent perceptions of conjugal power may have relatively high validity. Substantively, the data showed a positive association between the father's occupational prestige and his power concerning important family problems, general disagreements, and disagreements about income. Comparative father-mother education and the mother's employment status tended to have a positive association with conjugal power in all areas examined except child discipline where the two data sets were somewhat contradictory. The antecedents and consequences of conjugal power structure have captured the attention of a number of social scientists in recent years. These studies have been handicapped by a number of conceptual and methodological problems, including perceptual bias of respondent (Ferber, 1955; Heer, 1962, 1963; SafiliosRothschild, 1969, 1970; Turk and Bell, 1972). Observation of family interaction in artificial or natural settings is one possible solution to the problem of perceptual bias of husbands and wives, but such observations may be unrepresentative or artificial. Another possibility is to get reports of conjugal power from family members other than the husband and wife. Children, particularly adolescents, might be able to report marital power more objectively than husband or wife. Nor are they limited to a small number of unrepresentative or artificial observations, as an extra-familial observer may be. The adolescent's intimate view of his family may prove to be an acceptable supplement or alternative to other measures of conjugal power. The purpose of this study is to examine the validity of adolescent perceptions of conjugal power. Although several studies of conjugal power have used children's perceptions, little attention has been given to the validity of these perceptions. This study also provides data on the association of adolescent perceptions of conjugal power with the father's occupational status, comparative father-mother education, and the mother's employment status. Validity will be assessed primarily by the method usually termed construct validity. In this procedure, validity is based on empirical support for theoretical predictions, in this case predicitions about relationships between conjugal power and other variables. An examination of the convergence of results of different measures will also provide estimates of convergent validity (Campbell and Fiske, 1959).

Mechanical and optical characterization of an anelastic polymer at large strain rates and large strains

Abstract: Two constitutive relations have been determined from test results that characterize, respectively, the uniaxial and photomechanical behavior of a polyester-styrene copolymer for strain rates from 10−5 to 3×103 in./in./s and strains up to 40 percent. The high-strain-rate data were obtained by means of a split-Hopkinson-bar apparatus. Intermediate-strain-rate tests, performed with the aid of a drop tower, were reported in an earlier paper. Quasi-static experiments were conducted on a standard testing machine. A nonlinear, four-parameter, elastic-viscoplastic model was constructed which describes the mechanical behavior. The parameters were determined by a least-mean-squares curve-fitting procedure. The viscoplastic parameters were found to obey a power law in strain rate. The photomechanical model was found to be linear with strain well into the plastic-deformation region, while the slope of the strain-birefringence curve for each strain rate also varied by strain rate to a power.

Pressure and temperature formation of A3B compounds II. Nb3Ge, Nb3Sn, Nb3Pb, VIn and VPb

Abstract: The formation of the compounds Nb3Ge, Nb3Sn, Nb3Pb has been investigated under high pressures and temperatures (20–70 kbar, 800–2200 °C). A new f.c.c. phase of Nb3Sn has been synthetized; two cubic structures have been obtained from the reaction of niobium with lead and new structures for compounds of vanadium with lead or indium are also reported. The appearance of the A15 structure is discussed in terms of the ratios of the atomic radii of the elements and it is concluded that pressure helps its formation when the ratio r A r B is smaller than a critical value.

Release of β-Lysin from Platelets by Thrombin and by a Factor Produced in Heparinized Blood

Abstract: Removal of calcium by either citrate, oxalate, or ethylenediaminetetraacetate inhibited coagulation of blood at an early stage and prevented the release of beta-lysin from platelets. In contrast, heparin caused platelet agglutination and stimulated beta-lysin release in vitro and in vivo. This release was calcium dependent and may have been due to a calcium-dependent reaction in the blood coagulation sequence. Thrombin which by-passed the early calcium-dependent stages of coagulation directly stimulated the release of beta-lysin from platelets. However, thrombin alone or in combination with other plasma factors was not as effective in releasing beta-lysin as the regular coagulation process. Thrombin's platelet degranulating activity correlated with its beta-lysin releasing activity. In contrast to thrombin, staphylococcal coagulase, which also by-passed the calcium-dependent stages of coagulation, coagulated citrated blood without releasing beta-lysin. The release of beta-lysin has been observed previously in the absence of blood coagulation, but this is the first observation of coagulation without beta-lysin release. It is clear that beta-lysin is released from platelets during coagulation by the direct action of thrombin and that it may be released in an earlier calcium-dependent reaction.

ESR study of free radicals in irradiated single crystals of potassium hydroxylamine disulfonate

Abstract: Two free radicals formed when single crystals of potassium hydroxylamine disulfonate are irradiated with gamma rays at 77°K were studied by ESR. The ESR spectra result from a predominant center (radical A) exhibiting large 14N and 1H hyperfine splittings and from lesser amounts of Fremy's radical [ȮN(SO3)22−]. The g and hyperfine tensors of these radicals have been evaluated and are discussed. Radical A, whose identity remains in doubt, may be regarded as the precursor to Fremy's radical; on warming its lines decay and those of Fremy's radical are formed. Lines from radical A decrease in strength and those of the hydroxyl radical (ȮH) grow in strength when irradiated crystals are photolyzed at 77°K. The reverse reaction occurs in the dark; the hydroxyl radical disappears and radical A is reformed.

Suppression of photically evoked after-discharge bursting following administration of anticonvulsants in waking rats.

Abstract: Tridione, depakine and dilantin were examined with respect to their effect on the occurence of photically evoked after-discharge (AD) bursting It was observed that each of these anticonvulsants reliably suppressed AD bursting although tridione and depakine were significantly more effective than was dilantin These results were attributed to the locus of action of the anticonvulsants and suggest the usefulness of AD as an index of the effectiveness of thalamically active drugs

GROWTH, MORTALITY, AND HEMATOLOGY OF CUTTHROAT TROUT EXPERIMENTALLY INFECTED WITH THE BLOOD FLUKE Sanguinicola klamathensis*

Abstract: Studies were made of the growth, mortality, and blood changes of cutthroat trout (Salmo clarki) experimentally infected with the blood fluke, Sanguinicola klamathensis Wales 1958. Five hundred non-infected cutthroat trout fingerlings and 500 exposed to a population of 6000 Fluminicola fusca snails with a 6% prevalence of infection with the blood fluke S. klamathensis were maintained for several months. Following 3 months exposure to the blood fluke infection, the experimental group had 80% mortality. Packed cell volumes and oxyhemoglobin levels were reduced significantly in the experimental fish as compared to the controls. Control fish continued to grow logarithmically in total weight, while the experimental fish declined in total weight due to parasitism and mortality. There were significant differences between the two groups for the average weight per fish and the average length per fish during the period of mortality.

Habituation and the occurrence of photically evoked afterdischarges in the albino rat

Abstract: Photically evoked afterdischarge (AD) parameters were examined in albino rats during the time course of 1 h of iterative photic stimulation (515 light flashes). It was observed that percentage of AD elicitation, duration of AD activity, and number of spindle waves per AD increased and then subsequently decreased over time. The amplitude of the largest peak-to-peak wave per AD was unaffected by time. Greatest AD elicitation took place during the 5- to 15-min time segment following the initiation of iterative photic stimulation. Likewise, the last 5 min of iterative stimulation yielded the lowest AD elicitation scores. These data suggest the operations of an arousal continuum in the process of AD elicitation. It was also observed that spontaneous AD-like waves occurred in the visual cortex at irregular intervals that were not specifically correlated with the light flashes.

The Design and Production of Learner-Controlled Courseware for the TICCIT System: A Progress Report.

Abstract: The magnitude of the task of courseware development in the TICCIT project has required the development of well-defined and manageable techniques for courseware preparation. This paper reviews the problems involved and the team production techniques developed to overcome them.

Polypeptide Composition of Photosynthetic Membranes from Chlamydomonas reinhardi and Anabaena variabilis.

Abstract: Anabaena variabilis, a blue-green alga lacking chlorophyll b, shows an absence of the major 22 and 24 kilodalton polypeptides which are present in the photosynthetic membranes of Chlamydomonas reinhardi and higher plants. These data are consistent with other investigations which have shown that these polypeptides are associated with chlorophyll b in the chloroplasts of higher plants, and indicate the presence of a light harvesting chlorophyll-protein complex in higher plants which contains the chlorophyll b of the photosynthetic membrane.

Careers: "But what have you done for me lately?" - The Boss

Abstract: The older engineer, outflanked by technology or undercut by mismanagement, faces special employment problems. "Technological obsolescence" used to be reserved for the chrome creations of Detroit and a host of household wonders that managed to expire surprisingly soon after their warrantees ran out. Now it seems that engineers themselves may be joining their handiwork on the road to short-term oblivion. And taking a few evening classes or reading current technical literature isn't going to keep the wolf from the door. About the best insurance is literally demanding challenging assignments rather than accepting routine tasks. Another alternative is changing careers. After all, a good engineering education can lead to a lot more than slide rules and solder.

Direct Mixing and Combustion Efficiency Measurements in Ducted, Particle-Laden Jets

Abstract: Using water-cooled probes and hot-gas valves, gas-particle samples were withdrawn from the secondary duct of an air-augmented laboratory burner. Using a boron-loaded propdlant, air/fuel ratio and secondary duct pressure were varied from 12/1 to 32/1 and from 82 to 127 psia, respectively. From sample analysis of chlorine, argon (air tracer), boron, and boron oxide, radial and axial profiles of air, gaseous fuel, participate fuel and percent of boron combustion were determined. Particles and gases mixed at significantly different rates. Measured gasphase mixing rates were comparable to model predictions, which assumed particles to be in equilibrium with gases. Boron combustion efficiency varied markedly with duct position, air/fuel ratio and secondary chamber pressure. Low boron combustion efficiency resulted principally from delayed ignition of the gaseous fuels after dilution by air reduced resulting gas-phase temperatures below the boron ignition temperature. This was especially true at low secondary duct pressures.