6,978 research outputs found
Development of a Sinkhole Raveling Chart Based on Cone Penetration Test (CPT) Data
Naturally occurring sinkholes in Florida are formed when the soluble limestone bedrock weathers and creates cavities at its interface with the overburden finer-grained soils. The overburden soil then erodes into the limestone fissures, thus weakening the strength and holding capacity of the soil above. This initial stage of a sinkhole is referred to as soil raveling and is considered to be the most effective time to perform soil improvements measures, such as grouting, to mitigate further expansion of the subterranean void. Geotechnical engineers and scientists use subsurface exploration techniques such as Cone Penetration Testing (CPT) to stratify soils and estimate soil properties. This paper presents a CPT-based raveling chart, to be used in identifying raveled soils in Central Florida during initial subsurface exploration. The raveling-chart was developed by collecting a large sample of CPT data (i.e cone tip resistance, qc, and sleeve frictional resistance, fs) from multiple sites within the same geological formation. CPT data was grouped within three categories: collapsed sinkholes, suspected raveling, and no1n-raveled, and plotted using a scatter of data points with coordinates (fs, Qtn,); that is sleeve friction resistance, and normalized tip resistance. A simple statistical analysis was applied for the resulting data group to create envelopes, or threshold lines, which bound the data to create certain categories. The resulting chart provides quantifiable measure of sinkhole raveling due to soil erosion
Life sciences on-line: A study in hypermedia application
The main objective was to determine the feasibility of using a computer-based interactive information recall module for the Life Sciences Project Division (LSPD) at NASA, Johnson Space Center. LSPD personnel prepare payload experiments to test and monitor physiological functions in zero gravity. Training refreshers and other types of online help are needed to support personnel in their tasks during mission testing and in flight. Results of a survey of other hypermedia and multimedia developers and lessons learned by the developer of the LSPD prototype module are presented. Related issues and future applications are also discussed and further hypermedia development within the LSPD is recommended
Factors Affecting Outcomes Of Second Intent Healing Of Nasal Defects After Mohs Micrographic Surgery
Background: Reconstruction of nasal defects secondary to Mohs micrographic surgery (MMS) presents particular challenges related to the complex topography, skin quality, tissue laxity and functional and aesthetic concerns of the region. Factors affecting outcomes resulting from second intent healing (SIH) on the nose have not been well described.
Purpose: The purpose of the study was to identify factors impacting outcomes of SIH for nasal tumors following MMS.Methods: Retrospective analysis was performed of all nasal lesions treated with MMS followed by SIH from a single surgical center over a 1.5-year period. Ninety-six cases were included. Chart review was performed, and data was collected including age, gender, nasal site, tumor type, defect size, depth and number of MMS stages. Pre- and post-operative follow-up photographs were available for all cases. All five authors evaluated the photographs using the modified Manchester scar scale. Analysis was then conducted to identify features associated with good outcomes.
Results: Of the 96 tumors, thirty-nine lesions (40.6%) were located on the nasal tip (including supratip), 32 (33.3%) on the ala/alar groove, 17 (17.7%) on the sidewall, and eight (8.3%) on the dorsum. The average defect size was 0.83cm2 (diameter of 1.06 centimeters ± 0.4). Defect diameter and defect depth were the factors that significantly impacted scar outcome (p\u3c0.001) in multivariate analysis. No significant functional deficits were reported.
Conclusion: This retrospective study suggests that nasal defects with area less than 0.83cm2 (or 1.06 cm diameter) and depth of defect not extending beyond the superficial fat healed well by SIH regardless of location on the nose
Molecular Dynamics Simulation of Ga Penetration along Grain Boundaries in Al: a Dislocation Climb Mechanism
Many systems where a liquid metal is in contact with a polycrystalline solid
exhibit deep liquid grooves where the grain boundary meets the solid-liquid
interface. For example, liquid Ga quickly penetrates deep into grain boundaries
in Al, leading to intergranular fracture under very small stresses. We report
on a series of molecular dynamics simulations of liquid Ga in contact with an
Al bicrystal. We identify the mechanism for liquid metal embrittlement, develop
a new model for it, and show that is in excellent agreement with both
simulation and experimental data
Long non-coding RNAs in C. elegans
Thousands of long non-coding RNAs (lncRNAs) have been found in vertebrate animals, a few of which have known biological roles. To better understand the genomics and features of lncRNAs in invertebrates, we used available RNA-seq, poly(A)-site, and ribosome-mapping data to identify lncRNAs of C. elegans. We found 170 long intervening ncRNAs (lincRNAs), which had single- or multi-exonic structures that did not overlap protein-coding transcripts, and about sixty antisense lncRNAs (ancRNAs), which were complementary to protein-coding transcripts. Compared to protein-coding genes, the lncRNA genes tended to be expressed in stage-dependent manner. Approximately 25% of the newly identified lincRNAs showed little signal for sequence conservation and mapped antisense to clusters of endogenous siRNAs, as would be expected if they serve as templates and targets for these siRNAs. The other 75% tended to be more conserved and included lincRNAs with intriguing expression and sequence features associating them with processes such as dauer formation, male identity, sperm formation, and interaction with sperm-specific mRNAs. Our study provides a glimpse into the lncRNA content of a non-vertebrate animal and a resource for future studies of lncRNA function
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