1,347 research outputs found
Ivy Baker Priest, with white head covering, Olive Beech, and Neal Iverson at Waikiki Beach, May 1959
No full textWritten on back: Mrs. Beech, Mrs. Priest Neal Iverson H. Consul of Peru May 195
Historical Fiction Author Don Neal Discusses Cold War Activities in Alaska
No full textDuring the Cold War, the USA was concerned that Russia would invade Alaska and American intelligence officers created the Stay Behind Agent Program to counter. At this event, Don Neal, author of the Ben Hunnicutt series that includes Cross Kill, Warhead, and washtub Gold, discusses the Nike missile system, the top-secret anti-espionage campaign Operation Washtub, and other Cold War activities in Alaska
Effects of soil aggregates on debris-flow mobilization: Results from ring-shear experiments
No full textRates and styles of landslide motion are sensitive to pore-water pressure changes caused by changes in soil porosity accompanying shear deformation. Soil may either contract or dilate upon shearing, depending upon whether its initial porosity is greater or less, respectively, than a critical-state porosity attained after sufficiently high strain. We observed complications in this behavior, however, during rate-controlled (0.02 m s− 1) ring-shear experiments conducted on naturally aggregated dense loamy sand at low confining stresses (10.6 and 40 kPa). The aggregated soil first dilated and then contracted to porosities less than initial values, whereas the same soil with its aggregates destroyed monotonically dilated. We infer that aggregates persisted initially during shear and caused dilation before their eventual breakdown enabled net contraction. An implication of this contraction, demonstrated in experiments in which initial soil porosity was varied, is that the value of porosity distinguishing initially contractive from dilative behavior can be significantly larger than the critical-state porosity, which develops only after disaggregation ceases at high strains. In addition, post-dilative contraction may produce excess pore pressures, thereby reducing frictional strength and facilitating debris-flow mobilization. We infer that results of triaxial tests, which generally produce strains at least a factor of ∼ 4 smaller than those we observed at the inception of post-dilative contraction, do not allow soil contraction to be ruled out as a mechanism for debris-flow mobilization in dense soils containing aggregates.This article is published as Iverson, Neal R., Janet E. Mann, and Richard M. Iverson. "Effects of soil aggregates on debris-flow mobilization: Results from ring-shear experiments." Engineering Geology 114, no. 1-2 (2010): 84-92. DOI: 10.1016/j.enggeo.2010.04.006.</p
Coupling between a glacier and a soft bed: II Model results
No full textAbstractThe relation between the local effective pressure and shear stress on till beneath Storglaciären, Sweden, discussed in Iverson and others (1999), provides an empirical basis for studying the processes that control the strength of the ice/bed coupling. Particles in the bed that protrude into the glacier sole support shear stresses that are limited by either ploughing or the traditional sliding mechanisms. Model calculations, based on studies of cone penetration through fine-grained sediment and sliding theory, agree with the observed relation between shear stress and effective pressure if the water layer at the ice/bed interface is assumed to thicken rapidly as the effective pressure approaches zero. Studies of the hydraulics of linked cavities provide support for this assumption, if the mean thickness of the water layer reflects the extent of microcavity development at the interface. Comparison of the calculated shear stress with the ultimate strength of till suggests that bed deformation limits the shear stress on till beneath Storglaciären only at intermediate effective pressures; at very low effective pressures, like those inferred at the site of the tiltmeter discussed in Iverson and others (1999), and at sufficiently high effective pressures, ploughing and sliding should focus motion near the glacier sole. A calculation using parameter values appropriate for Ice Stream B, West Antarctica, suggests that ploughing may occur there at shear stresses not sufficient to deform the bed at depth. This conclusion is reinforced by the likelihood that pore pressures in excess of hydrostatic should develop down-glacier from ploughing particles, thereby weakening the bed near the glacier sole. However, given the apparent sensitivity of the ice/bed coupling to basal conditions that may be highly variable, any blanket assumption regarding the flow mechanism of ice masses on soft beds should probably be viewed with skepticism.</jats:p
Material Spirituality with Neal DeRoo Pt. I
No full textIs spirituality one part of our lives that we experience in worship? Or does it permeate our whole being? Are we able to pull spirituality and religion apart? What would happen if we considered how our spirituality is embodied, deeply, in our world? In this inaugural episode of Critical Faith, Neal DeRoo explores these questions in his lecture "Toward a Material Spirituality: Religion and Phenomenological Expression." The recording is the first of three parts, all from a Scripture, Faith, and Scholarship Seminar hosted at the Institute for Christian Studies.
Neal DeRoo is Canada Research Chair in Phenomenology and Philosophy of Religion and Associate Professor of Philosophy at The King's University in Edmonton, Alberta, and the author of Futurity in Phenomenology: Promise and Method in Husserl, Levinas, and Derrida (Fordham: 2013)
Volcano collapse promoted by progressive strength reduction: new data from Mount St. Helens
No full textRock shear strength plays a fundamental role in volcano flank collapse, yet pertinent data from modern collapse surfaces are rare. Using samples collected from the inferred failure surface of the massive 1980 collapse of Mount St. Helens (MSH), we determined rock shear strength via laboratory tests designed to mimic conditions in the pre-collapse edifice. We observed that the 1980 failure shear surfaces formed primarily in pervasively shattered older dome rocks; failure was not localized in sloping volcanic strata or in weak, hydrothermally altered rocks. Our test results show that rock shear strength under large confining stresses is reduced ∼20% as a result of large quasi-static shear strain, as preceded the 1980 collapse of MSH. Using quasi-3D slope-stability modeling, we demonstrate that this mechanical weakening could have provoked edifice collapse, even in the absence of transiently elevated pore-fluid pressures or earthquake ground shaking. Progressive strength reduction could promote collapses at other volcanic edifices.This article is published as Reid, Mark E., Terry EC Keith, Robert E. Kayen, Neal R. Iverson, Richard M. Iverson, and Dianne L. Brien. "Volcano collapse promoted by progressive strength reduction: new data from Mount St. Helens." Bulletin of Volcanology 72, no. 6 (2010): 761-766. DOI: 10.1007/s00445-010-0377-4. </p
Deciphering Landslide Behavior Using Large-scale Flume Experiments
No full textLandslides can be triggered by a variety of hydrologic events and they can exhibit a wide range of movement dynamics. Effective prediction requires understanding these diverse behaviors. Precise evaluation in the field is difficult; as an alternative we performed a series of landslide initiation experiments in the large-scale, USGS debris-flow flume. We systematically investigated the effects of three different hydrologic triggering mechanisms, including groundwater exfiltration from bedrock, prolonged rainfall infiltration, and intense bursts of rain. We also examined the effects of initial soil porosity (loose or dense) relative to the soil’s critical-state porosity. Results show that all three hydrologic mechanisms can instigate landsliding, but water pathways, sensor response patterns, and times to failure differ. Initial soil porosity has a profound influence on landslide movement behavior. Experiments using loose soil show rapid soil contraction during failure, with elevated pore pressures liquefying the sediment and creating fast-moving debris flows. In contrast, dense soil dilated upon shearing, resulting in slow, gradual, and episodic motion. These results have fundamental implications for forecasting landslide behavior and developing effective warning systems.This proceeding is published as Reid, Mark E., Richard M. Iverson, Neal R. Iverson, Richard G. LaHusen, Dianne L. Brien, and Matthew Logan. "Deciphering Landslide Behavior Using Large-scale Flume Experiments."In Proceedings of the First World Landslide Forum. The First World Landslide Forum. Tokyo, Japan. November 18-21, 2008. </p
Debris-bed friction during glacier sliding with ice–bed separation
No full textTheory and experiments indicate that ice–bed separation during glacier slip over 2-D hard beds causes basal shear stress to reach a maximum at a particular slip velocity and decrease at higher velocities. We use the sliding theory of Lliboutry (1968) to explore how friction between debris particles in sliding ice and a rock bed affects this relationship between shear stress and slip velocity. Particle–bed contact forces and associated debris friction increase with increasing slip velocity, owing to increased rates of ice convergence with up-glacier facing surfaces. However, debris friction on diminished areas of the bed counteracts this effect as cavities grow. Thus, friction from debris alone increases only slightly with slip velocity, and for sediment particles larger than ~60 mm in diameter, debris friction peaks and decreases with increasing slip velocity. The effect on the sliding relationship is to steepen its rising limb and shift its shear stress peak to a slightly higher velocity. These results, which exclude the effect of debris friction on cavity size and debris concentrations above ~15%, indicate that the effect of debris in ice is to increase basal shear stress but not significantly change the form of the sliding relationship.This article is published as Iverson, Neal R., Christian Helanow, and Lucas K. Zoet. "Debris-bed friction during glacier sliding with ice–bed separation." Annals of Glaciology 60, no. 80 (2019): 30-36. doi: 10.1017/aog.2019.46.</p
Grace Neal Parkway design concept report
No full textabstract: Grace Neal Parkway and Bank Street are located in the northern Kingman area partially outside of the Kingman city limits. This report discusses of creating a new arterial roadway providing safety and convenience for vehicular traffic and pedestrians. Although Grace Neal is referred to as a parkway, its designation for design is arterial.Stockton Hill Road to SR-66; Bank Street assessment, Northern Avenue to Grace Neal Parkway
From the Editor. Decription of author John Neal, his book Portland Illustrate
No full textFrom the Editor. Decription of author John Neal, his book Portland Illustrated (published in 1874), and his relationships with art critic N.C. Willis, Lady Blessington, and painter Charles Codman
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