490 research outputs found
NSDL EduPak: An Open Source Education Repository Solution
4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PostersEducational organizations and institutions focused on establishing specialized digital collections, conducting educational research, or providing students, teachers and instructors with discipline-oriented pedagogical products and tools require basic technology to begin building educational digital repositories. To help meet these needs, the National Science Digital Library (NSDL) has announced the release of NSDL EduPak. Specifically designed for education, NSDL EduPak packages technology for digital storage, access, and workflow into a convenient bundle. This poster reviews three core EduPak components with examples of how they are used by education communities.National Science Foundatio
Synthesis and Characterization of Graphene Oxide/Sulfur Nanocomposite for Lithium-Ion Batteries
The growing need for clean and efficient energy storage systems has recently peaked due to concerns of climate change and increased global energy consumption. However, efficiently integrating renewable resources such as solar and wind energy into society will require a complex electrical energy storage (EES) system capable of storing and expending significant amounts of energy. A battery based on the lithium/sulfur couple can yield a theoretical specific energy of 2600Wh/kg, which is about five times higher than that offered by present Li-ion batteries, and hence, is a promising and attractive technology. Despite recent developments in addressing various issues inherent to a sulfur cathode, the lithium/sulfur couple continues to exhibit capacity fade over cycling. The present study uses a low cost, solution-based reaction to heterogeneously nucleate and grow sulfur within the graphene oxide (GO) matrix. The reactive functional groups on GO work to entrap sulfur, thereby reducing polysulfide dissolution and improving electrochemical stability. Morphologies, compositions, and structures of the as-prepared GO/S nanocomposites were characterized using SEM, XRD, TGA, DSC, and EDX. Performance characteristics were electrochemically determined via discharge/charge cycling, and were compared against mechanically mixed GO/S composites. The optimized GO/S nanocomposite was then combined with a graphene-based anode, forming a novel Li-ion/S cell configuration. The replacement of the metallic lithium anode is anticipated to overcome numerous issues afflicting the Li/S battery concept. It is found that selection of an electrolyte compatible with both GO anode and GO/S cathode is critically important to achieve better performance for a graphene-based Li-ion/S cell, which is subjected to further studies
Trends in Respirable Coal Mine Dust Concentration (mg/m3) based on Coal Miners’ Occupational Designation: An Analysis of the MSHA Coal Dust Samples Data Set (2000-2022)
Rates of Coal Workers\u27 Pneumoconiosis (CWP) have recently increased in prevalence over the past 20 years. Recent regulation (Phase III) by the Mining Safety and Health Administration to lower the coal dust standard to 1.5 mg/m3 has been mandated to assist in reducing the burden of CWP. Occupations in the coal mining industry have different exposures to coal dust depending on their occupational responsibilities. This study examined the respirable coal dust trends for underground and surface mining occupations from 2000 to 2022. The ultimate goal is to see how respirable coal dust exposures have changed in multiple occupations over this period and ensure mines meet the MSHA Phase III standard
Self Super-Resolution for Magnetic Resonance Images using Deep Networks
High resolution magnetic resonance~(MR) imaging~(MRI) is desirable in many
clinical applications, however, there is a trade-off between resolution, speed
of acquisition, and noise. It is common for MR images to have worse
through-plane resolution~(slice thickness) than in-plane resolution. In these
MRI images, high frequency information in the through-plane direction is not
acquired, and cannot be resolved through interpolation. To address this issue,
super-resolution methods have been developed to enhance spatial resolution. As
an ill-posed problem, state-of-the-art super-resolution methods rely on the
presence of external/training atlases to learn the transform from low
resolution~(LR) images to high resolution~(HR) images. For several reasons,
such HR atlas images are often not available for MRI sequences. This paper
presents a self super-resolution~(SSR) algorithm, which does not use any
external atlas images, yet can still resolve HR images only reliant on the
acquired LR image. We use a blurred version of the input image to create
training data for a state-of-the-art super-resolution deep network. The trained
network is applied to the original input image to estimate the HR image. Our
SSR result shows a significant improvement on through-plane resolution compared
to competing SSR methods.Comment: Accepted by IEEE International Symposium on Biomedical Imaging (ISBI)
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Air quality in Mecca and surrounding holy places in Saudi Arabia during Hajj: initial survey.
The Arabian Peninsula experiences severe air pollution, the extent and sources of which are poorly documented. Each year in Saudi Arabia this situation is intensified during Hajj, the Holy Pilgrimage of Islam that draws millions of pilgrims to Mecca. An initial study of air quality in Mecca and surrounding holy sites during the 2012 Hajj (October 24-27) revealed strongly elevated levels of the combustion tracer carbon monoxide (CO, up to 57 ppmv) and volatile organic compounds (VOCs) along the pilgrimage route-especially in the tunnels of Mecca-that are a concern for human health. The most abundant VOC was the gasoline evaporation tracer i-pentane, which exceeded 1200 ppbv in the tunnels. Even though VOC concentrations were generally lower during a follow-up non-Hajj sampling period (April 2013), many were still comparable to other large cities suffering from poor air quality. Major VOC sources during the 2012 Hajj study included vehicular exhaust, gasoline evaporation, liquefied petroleum gas, and air conditioners. Of the measured compounds, reactive alkenes and CO showed the strongest potential to form ground-level ozone. Because the number of pilgrims is expected to increase in the future, we present emission reduction strategies to target both combustive and evaporative fossil fuel sources
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