12,894 research outputs found
Experiments with ceramic coatings
Report describes the procedures and techniques used in the application of a ceramic coating and the evaluation of test parts through observation of the cracks that occur in this coating due to loading
Trigger Warnings & Reactions to Literature: Sexual Victimization and Emotional Responses to Difficult Literature
Trigger warnings have been a cause for concern nationwide, and it remains unclear whether they truly protect students with varying histories of sexual assault trauma when exposed to triggering experiences. The sample consisted of 62 participants enrolled in an Introduction to Psychology course at Bucknell in the Fall 2017 and Spring 2018 semesters. Students responded to a three-part survey, filling out a prior sexual victimization scale, a life events checklist, a PTSD checklist, a distress scale, a research participation scale, and demographic questions in response to reading an emotionally distressing, “triggering” passage from Toni Morrison’s “The Bluest Eye.” Participants were also able to opt-out of the triggering passage and read a neutral passage instead. Follow-up online surveys with a distress scale and adapted PTSD checklist based on the passage were sent to participants two days and two weeks after initially reading the passage. Three hypotheses were tested: First, it was expected that participants who have experienced any trauma would report more emotional distress to the triggering passage than those without a trauma history; second, it was expected that students who have a history of sexual trauma would report more emotional distress to the triggering passage than those without such history; and third, participants with PTSD would report more emotional distress to the triggering passage than those without PTSD. Results show that participants had prolonged emotional distress over the two week testing period, with victims of sexual assault indicating higher scores on measures of emotional distress and an adapted PTSD checklist in response to the literature. As one of the most common forms of trauma for college students is sexual assault, it is essential to know whether trigger warnings can be used in college courses in order to avoid negative traumatic reactions from students when completing assignments
Antiferromagnetic Order of the Ru and Gd in Superconducting RuSr2GdCu2O8
Neutron diffraction has been used to study the magnetic order in
RuSr{2}GdCu2O8. The Ru moments order antiferromagnetically at T{N}=136(2)K,
coincident with the previously reported onset of ferromagnetism. Neighboring
spins are antiparallel in all three directions, with a low T moment of 1.18(6)
mu {B} along the c-axis. Our measurements put an upper limit of ~0.1 mu{B} to
any net zero-field moment, with fields exceeding ~0.4T needed to induce a
measurable magnetization. The Gd ions order independently at T{N}=2.50(2)K with
the same spin configuration. PACS numbers: 74.72.Jt, 75.25.+z, 74.25.Ha,
75.30.KzComment: Four pages, Latex, 5 eps figure
Distinguishability of hyperentangled Bell state by linear evolution and local projective measurement
Measuring an entangled state of two particles is crucial to many quantum
communication protocols. Yet Bell state distinguishability using a finite
apparatus obeying linear evolution and local measurement is theoretically
limited. We extend known bounds for Bell-state distinguishability in one and
two variables to the general case of entanglement in two-state variables.
We show that at most classes out of hyper-Bell states can be
distinguished with one copy of the input state. With two copies, complete
distinguishability is possible. We present optimal schemes in each case.Comment: 5 pages, 2 figure
Remediation of Contaminated Soils by Solvent Flushing
Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, and increases the release rates of the contaminants. A simulation model is developed to predict contaminant elution curves during solvent flushing for the case of one‐dimensional, steady flow through a contaminated medium. Column experiments are conducted with a Eustis fine sand that is initially equilibrated with an aqueous naphthalene solution, and then eluted with different methanol‐water mixtures to remove the naphthalene. The model simulations, based on parameter values estimated from literature data, agree well with the measured elution profiles. Solvent flushing experiments, where the soil was initially equilibrated with a solution of naphthalene and anthracene, show that compounds with different retardation factors are separated at low cosolvent contents, while coelution of the compounds occurs at higher contents. In general, the smaller the retardation factor in water and the higher the cosolvent fraction, the faster the contaminant is recovered. The presence of nonequilibrium conditions, soil heterogeneity, and type of cosolvent will influence the time required to recover the contaminant.\u
Auxiliary field diffusion Monte Carlo calculations of light and medium-mass nuclei with local chiral interactions
Quantum Monte Carlo methods have recently been employed to study properties
of nuclei and infinite matter using local chiral effective field theory
interactions. In this work, we present a detailed description of the auxiliary
field diffusion Monte Carlo algorithm for nuclei in combination with local
chiral two- and three-nucleon interactions up to next-to-next-to-leading order.
We show results for the binding energy, charge radius, charge form factor, and
Coulomb sum rule in nuclei with . Particular attention is devoted
to the effect of different operator structures in the three-body force for
different cutoffs. The outcomes suggest that local chiral interactions fit to
few-body observables give a very good description of the ground-state
properties of nuclei up to O, with the exception of one fit for the
softer cutoff which predicts overbinding in larger nuclei.Comment: 23 pages, 10 figure
Pedogenic Processes in Thick Sand Deposits on a Marine Terrace, Central California
Pedological studies in thick sedimentary sequences are generally limited to the upper few meters. Field investigation of thick (~50 m) sand deposits on an emergent Pleistocene marine terrace in central California showed morphological differences between the solum at the surface and the deep regolith. Based on morphological and geochemical features, four units were identified within the regolith. Two zones of active pedogenesis occur within three of these units. The surficial unit is in Holocene sand deposits (mixed, thermic, Argic Xeropsamments), and has darkened A horizons, a slightly reddened subsoil, and incipient lamellae at the depth of wetting front infiltration. These lamellae have slightly more day and Fe oxides than the soil above. Mineral weathering is intense at the surface. The other zone of active pedogenesis is at the base of the regolith, where a lithologic discontinuity above the terrace platform forms an aquitard, and throughflow occurs. Meteoric water percolates through thin regolith deposits above the shoreline angle, and at other locations on the terrace where sediment has been removed by erosion. Percolating water carries clay, organic matter, and solutes to the water table. Weathering is intense within this basal unit. Illuviation of clays and Fe oxides, and precipitation of Fe oxides and silica occur within this unit. As pore space is filled, fractures and channels become paths for saturated water flow. Eluviation of Fe occurs at these sites. Most of the intervening regolith is isolated from current pedogenesis by its great depth and a relatively dry Holocene climate. Well-developed lamellae are preserved as relicts of Pleistocene episodes of soil formation. These lamellae formed by illuviation of clay and Fe oxides, and were sites of silica precipitation. The conceptual model presented here is intended to facilitate understanding of pedogenic and geomorphological evolution of marine terrace deposits, and to assist with the interpretation of groundwater flow in these terrace systems
Caribou distribution during calving in the northeast National Petroleum Reserve-Alaska, June 1998 to 2000
Barren ground caribou (Rangifer tarandus granti) of the Teshekpuk Caribou Herd (TCH) inhabit the western portion of Alaska's Arctic Coastal Plain within the National Petroleum Reserve—Alaska (NPR-A). Alaska's North Slope communities, management agencies, and private industry are interested in this herd because of its importance as a subsistence resource and location relative to potential petroleum development. From 1998 through 2000, we monitored caribou distribution during the calving period within the Northeast Planning Area of the NPR-A using systematic strip-transect aerial surveys, as well as VHF and satellite telemetry for cow caribou. Aerial survey and telemetry data indicated cows with calves were distributed around Teshekpuk Lake, with a concentration south of the lake in 1999 and 2000. Inconsistencies in weather conditions, survey timing (both strip-transect and VHF surveys), 100% coverage survey areas, and small sample sizes confound interpretations of our results. However, several patterns were apparent. Later transect survey timing (7—12 June versus 4—7 and 5—8 June) resulted in more cow/calf pairs recorded. Our 18% coverage area, originally based on VHF telemetry data for the extent of TCH calving, covered a consistently high proportion (95% to 100%) of the annual calving ranges (95% kernel utilization distributions), but accounted for only 24% to 46% of the adult cows in the TCH based on the current Alaska Department of Fish and Game population estimate (1999) and average 1998¬2000 herd composition. It appears that either our transect survey methodology significantly underestimated the true number of caribou cows in the study area, many cows calved outside the area or moved into the area and calved after our surveys, or we have over estimated the number of reproductive cows in the herd. Our 100% coverage transect areas covering oil and gas lease areas, contained 38% of the calving range with 23% of TCH cows in 1999; and 18% of the calv¬ing range with 8% of TCH cows in 2000. Based on 95% minimum convex polygon ranges, satellite collared cow/calf pairs were not stationary during either our survey period (14.7 ± 6.56 km2; mean ± standard error of the mean; 4—12 June) or during the calving period (86.9 ± 72.30 km2; 1—20 June) during 1998—2000. Site specific pre-development data on caribou distribution during calving in NPR-A will be useful for assessing the importance of specific areas to caribou during calving and for designing oilfields that minimize impacts should oil development occur
Canopy Characteristics, Ingestive Behaviour and Herbage Intake in Cultivated Tropical Grasslands
Compared to temperate systems, there have been few detailed assessments of canopy characteristics and associated grazing behavior in planted tropical grasslands. Reasons include the large number of forage species used in warm climates, the diversity of their morphology, research priorities emphasizing germplasm evaluation and management, and limited resources. This review describes canopy attributes of C4 grass pastures, highlights the most important relationships between grazing behavior and these canopy characteristics, and discusses the implications of canopy characteristics and grazing behavior for long-term intake and animal performance. It is suggested that the largest differences in canopy characteristics between tropical and temperate swards are not total canopy measures but those of the upper canopy strata including leaf proportion and bulk density. This occurs because tropical swards, unlike many temperate ones, have large vertical heterogeneity in density, plant-part proportion and nutritive value. In temperate swards, bite weight is primarily a function of sward height, but leaf percentage, leaf mass, or green herbage mass of the upper strata of the canopy usually are more important with C4 grasses. The manner in which leaf is presented to the animal and the degree to which it can be prehended separate from stem and dead material of low digestibility are also of great significance in pastures based on C4 grasses
Neutron diffraction in a model itinerant metal near a quantum critical point
Neutron diffraction measurements on single crystals of Cr1-xVx (x=0, 0.02,
0.037) show that the ordering moment and the Neel temperature are continuously
suppressed as x approaches 0.037, a proposed Quantum Critical Point (QCP). The
wave vector Q of the spin density wave (SDW) becomes more incommensurate as x
increases in accordance with the two band model. At xc=0.037 we have found
temperature dependent, resolution limited elastic scattering at 4
incommensurate wave vectors Q=(1+/-delta_1,2, 0, 0)*2pi/a, which correspond to
2 SDWs with Neel temperatures of 19 K and 300 K. Our neutron diffraction
measurements indicate that the electronic structure of Cr is robust, and that
tuning Cr to its QCP results not in the suppression of antiferromagnetism, but
instead enables new spin ordering due to novel nesting of the Fermi surface of
Cr.Comment: Submitted as a part of proceedings of LT25 (Amsterdam 2008
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