7,959 research outputs found
Fiber pulling apparatus modification
A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. Four flights have been completed to date during which E-glass fiber was successfully produced in simulated zero, high, and lunar gravity environments. In addition simulated lunar soil samples were tested for their fiber producing properties using the FPA
Detection and Analysis of Spatiotemporal Changes in Great Basin Groundwater Dependent Vegetation Vigor
Throughout much of the arid Western United States, groundwater-dependent ecosystems (GDEs; those in which the flora necessarily rely on surface expressions of groundwater) represent hotspots of biodiversity, providing pockets of rich mesic habitat in an otherwise arid landscape. Yet, despite their integral ecological role, little is known about the long term dynamic spatiotemporal response of GDEs in arid lands to both disturbance and climatic variability. Climate change and anthropogenic groundwater abstraction have combined to drastically alter the hydrologic regime throughout regions of the Great Basin. As such, anthropogenically induced or exacerbated hydrologic disturbance have placed springs, wetlands, phreatophytic flats and a slough of additional Great Basin GDEs under intense environmental stress. Given the ecological and economic value of the many ecosystem services these unique environments perform, improving understanding of their spatiotemporal dynamics such that resource managers may simultaneously meet the needs of both humans and nature, is of the utmost importance. Remotely sensed vegetation indices (VI) are commonly used proxies for estimating vegetation vigor and net primary productivity across many terrestrial ecosystems, though limitations in data availability and computing power have historically confined these analyses both spatially and temporally. In this work, however, spatiotemporally vast analyses of GDE vegetation vigor change through space and time were conducted using Google’s Earth Engine (EE) cloud computing and environmental monitoring platform. This platform allows for the streamlining of computationally intense environmental analyses, and to access pre-processed Landsat archive and gridded meteorological data, effectively overcoming the temporal and spatial constraints previously posed by limited economic resources and computing power. Results of Landsat derived GDE vegetation vigor and associated environmental variable time series’ and trend analyses illustrate the existence of a strong and highly significant coupling between depth to groundwater (DTG) and GDE vegetation vigor. Further, it was found that the presence of groundwater-vegetation feedbacks renders these systems highly prone to irreversible transitions to alternative, often barren or xerophytic, ecohydrological states, should a given GDE become decoupled from shallow groundwater resources as a result of surpassing species and tissue specific soil moisture threshold values
Introducing A Peer Review System Targeting Shared Understanding and Actionable Feedback
This paper looks at some of the potential benefits peer review offers and someof the difficulties. It examines my attempts to develop and trial a teachingapproach activating the advantages and mitigating the potential difficultiesinvolved in peer review. It also considers how to address culturally specificchallenges possibly inhibiting successful peer review for Japanese students.The approach is described in a cycle of four demarcated steps: (a) the reviewercommenting on observable facts, (b) the reviewer adding appropriate advice,(c) the reviewer adding praise and/or evaluation and (d) the revieweereevaluating the essay in light of the feedback and analyzing options.Classroom observations and feedback from students in tutorials suggest thisapproach and the system of steps seem to facilitate smoother and moreeffective peer review and assist in developing writing revision skills. Thiscould be due to the construction of a shared understanding for the peer reviewprocess by using the four-step framework
Experimental studies on the development of heavy claypans in soils
Publication authorized May 21, 1934."Submitted in partial fulfillment of the Requirements for the Degree of Master of Arts in the Graduate School of the University of Missouri, 1934"--P. [3].Includes bibliographical references (page 31)
Localized shear generates three-dimensional transport
Understanding the mechanisms that control three-dimensional (3D) fluid
transport is central to many processes including mixing, chemical reaction and
biological activity. Here a novel mechanism for 3D transport is uncovered where
fluid particles are kicked between streamlines near a localized shear, which
occurs in many flows and materials. This results in 3D transport similar to
Resonance Induced Dispersion (RID); however, this new mechanism is more rapid
and mutually incompatible with RID. We explore its governing impact with both
an abstract 2-action flow and a model fluid flow. We show that transitions from
one-dimensional (1D) to two-dimensional (2D) and 2D to 3D transport occur based
on the relative magnitudes of streamline jumps in two transverse directions.Comment: Copyright 2017 AIP Publishing. This article may be downloaded for
personal use only. Any other use requires prior permission of the author and
AIP Publishin
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