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This dataset contains data from E-Defense shake-table tests of a full-scale, steel moment-resisting frame (MRF) supplemented with spines. Herein, the spines were pin-based columns with sufficient stiffness and strength to distribute plastic deformation evenly over the height of the MRF. The specimen was tested under two configurations: first, with the spine rigidly connected to the MRF; and second, with the spine connected to the MRF through Force-Limiting Connections (FLCs). The two structural systems were subjected to two ground motions adjusted to two different scales. The tests highlighted the expected benefits of spines as well as their drawbacks of inducing large floor acceleration in the MRF and large shear forces in the spines themselves. The tests also highlighted how the FLCs can mitigate such drawbacks of spines. The data may be used, for example, to reproduce the observations presented by the authors, to compare the dynamic response of the specimen with building specimens tested in other shake-table test programs, to validate numerical models against the measured specimen response, or to formulate classroom exercises on system identification of linear and nonlinear systems.
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Zooglider-Based Measurements of Planktonic Foraminifera in the California Current System
Abstract Spines and rhizopodia play an important role in the feeding behavior, symbiont ecology, shell geochemistry, and density and drag of planktonic foraminifera. However, there are few empirical data on planktonic foraminifera in situ, and these delicate structures are disturbed on capture. Here, we report spine and rhizopod measurements from underwater images obtained in the California Current System near La Jolla, California by Zooglider, a new autonomous zooplankton-sensing glider. Across all observed species, we find that spine length and flexibility correlate with test size and that spines increase the effective prey encounter volume of spinose foraminifera by two to three orders of magnitude. Our data also yielded several novel observations regarding hastigerinid foraminifera (Hastigerinella digitata and Hastigerina pelagica), a group of unusually large planktonic foraminifera that are abundant in our dataset below 250 m. First, the effective encounter volume of hastigerinid foraminifera can be very large: our largest specimen occupies almost 40 cm3 (about the size of a golf ball), while the median specimen occupies 5.3 cm3 (about the size of a cherry). Second, the majority of hastigerinid foraminifera in our dataset have asymmetric bubble capsules, which are most frequently oriented with their bubbles on the upward side of the test, consistent with the hypothesis that the bubble capsule is positively buoyant. Third, 16% of hastigerinid foraminifera in our dataset have dispersed bubble capsules with detached bubbles distributed along the spines and rhizopodia, consistent with a regular source of natural disturbance. Taken together, our observations suggest that hastigerinid foraminifera play a larger role as mesopelagic predators in the California Current System than previously recognized.
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- Award ID(s):
- 1637632
- PAR ID:
- 10156890
- Date Published:
- Journal Name:
- Journal of Foraminiferal Research
- Volume:
- 49
- Issue:
- 4
- ISSN:
- 0096-1191
- Page Range / eLocation ID:
- 390 to 404
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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ABSTRACT This data paper presents data obtained from E‐Defense shake‐table tests of a full‐scale, steel moment‐resisting frame (MRF) supplemented with Spines. Herein, the Spines were pin‐based columns with sufficient stiffness and strength to distribute plastic deformation evenly over the height of the MRF. The specimen was tested under two configurations: first, with the Spine rigidly connected to the MRF; second, with the Spine connected to the MRF through force‐limiting connections (FLCs). Each specimen configuration underwent earthquake simulations using ground motions with two scale factors. The tests demonstrated the expected benefits of Spines as well as the disadvantage of inducing large floor accelerations in the structure and large shear forces in the Spines. The tests also demonstrated how the FLCs can mitigate these disadvantages. This data paper reports an overview of the tests, data archive structure, and potential use of the data. The data can be used, for example, to reproduce the observations presented by the authors, to compare the dynamic response of the specimen with building specimens tested in other shake‐table test programs, to validate numerical models against the measured specimen response, or to formulate classroom exercises on system identification of linear and nonlinear systems.more » « less
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null (Ed.)Synopsis Puncture mechanics can be studied in the context of predator–prey interactions and provide bioinspiration for puncture tools and puncture-resistant materials. Lionfish have a passive puncture system where venomous spines (dorsal, anal, and pelvic), the tool, may embed into a predator’s skin, the target material, during an encounter. To examine predator–prey interactions, we quantified the puncture performance of red lionfish, Pterois volitans, spines in buccal skin from two potential predators and porcine skin, a biological model for human skin. We punctured dorsal, anal, and pelvic lionfish spines into three regions of buccal skin from the black grouper (Mycteroperca bonaci) and the blacktip shark (Carcharhinus limbatus), and we examined spine macro-damage (visible without a microscope) post puncture. Lionfish spines were more effective, based on lower forces measured and less damage incurred, at puncturing buccal skin of groupers compared to sharks. Anal and dorsal spines incurred the most macro-damage during successful fish skin puncture trials, while pelvic spines did not incur any macro-damage. Lionfish spines were not damaged during porcine skin testing. Anal spines required the highest forces, while pelvic spines required intermediate forces to puncture fish skin. Dorsal spines required the lowest forces to puncture fish skins, but often incurred macro-damage of bent tips. All spine regions required similar forces to puncture porcine skin. These data suggest that lionfish spines may be more effective at puncturing humans such as divers than potential fish predators. These results emphasize that puncture performance is ultimately determined by both the puncture tool and target material choice. Lionfish puncture performance varies among spine region, when taking into account both the puncture force and damage sustained by the spine.more » « less
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Dendritic spines are small subcompartments that protrude from the dendrites of neurons and are important for signaling activity and synaptic communication. These subcompartments have been characterized to have different shapes. While it is known that these shapes are associated with spine function, the specific nature of these shape–function relationships is not well understood. In this work, we systematically investigated the relationship between the shape and size of both the spine head and spine apparatus, a specialized endoplasmic reticulum compartment within the spine head, in modulating rapid calcium dynamics using mathematical modeling. We developed a spatial multicompartment reaction–diffusion model of calcium dynamics in three dimensions with various flux sources, including N-methyl-D-aspartate receptors (NMDARs), voltage-sensitive calcium channels (VSCCs), and different ion pumps on the plasma membrane. Using this model, we make several important predictions. First, the volume to surface area ratio of the spine regulates calcium dynamics. Second, membrane fluxes impact calcium dynamics temporally and spatially in a nonlinear fashion. Finally, the spine apparatus can act as a physical buffer for calcium by acting as a sink and rescaling the calcium concentration. These predictions set the stage for future experimental investigations of calcium dynamics in dendritic spines.more » « less
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Abstract Squeezing bubbles in a tapered microgap has proved to be effective for improving flow stability in flow boiling. A previous study from our research group has successfully demonstrated using tapered microgap for transforming pool boiling into a self-sustained flow boiling-like system for cooling CPU through thermosiphon. To overcome the imaging challenges with nucleating vapor bubbles, the present work investigates the squeezing behaviour of air-injected bubbles between a tapered microgap with taper angles of 5°, 10°, and 15°. The air bubbles are injected at a rate of 3 ml/min, 15ml/min, and 30 ml/min in a pool of water. The bubble squeezing is recorded at 2000fps using a Photron high-speed camera. The experimental analysis compares the displacement and velocity of the advancing and receding bubble interfaces. The analysis found that in certain test cases, multiple bubbles coalesced while exiting the tapered microgap. In all the test cases, the receding interface of the bubble slingshots after detaching pushes the bubble out of the tapered microgap. The result from the current study provides an insight into the bubble flow and squeezing behavior that can be used for optimizing taper microgap geometries to enhance critical heat flux and heat transfer coefficient of two-phase, and air-injected single-phase heat transfer systems.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.2113/gsjfr.49.4.390
