Correction to “Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge”

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 34 (2007): L02603, doi:10.1029/2006GL028747

Sleep as an Occupation in College Students

The purpose of this study was to measure the quality of sleep in undergraduate college students and explore the relationship between academic self-efficacy and performance in student-related occupations. A quantitative, exploratory, descriptive and correlational research design was used to explore the relationship among sleep quality, perceived self-efficacy, and selected student characteristics. This study included undergraduate students, as well as self-identified student athletes, first generation students, and students with disabilities. To collect data, the researchers conducted an online survey, which consisted of the Pittsburgh Sleep Quality Index (PSQI), a demographic and self-efficacy questionnaire. The PSQI was used to evaluate the sleep quality, while the demographic and self-efficacy questionnaire gathered information about student related occupations and self-efficacy. Two hundred and nine college students, aged 17 to 25, participated in the survey. One hundred thirty five (64.6%) participants scored above a five, indicating poor sleep quality while 74 (35.4%) participants obtained good sleep quality as measured by the PSQI, while. The average number of hours slept reported by participants was 6.68. Results support existing evidence suggesting college students are sleep deprived, and over half of participants reported sleep issues that could be addressed by an occupational therapist.https://scholar.dominican.edu/ug-student-posters/1013/thumbnail.jp

Mercury contamination and cycling in the coastal zone

pp. 127-13

Characterization of ZnO Nanorods Grown on GaN Using Aqueous Solution Method

Uniformly distributed ZnO nanorods with diameter 70-100 nm and 1-2μm long have been successfully grown at low temperatures on GaN by using the inexpensive aqueous solution method. The formation of the ZnO nanorods and the growth parameters are controlled by reactant concentration, temperature and pH. No catalyst is required. The XRD studies show that the ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane. The room temperature photoluminescence measurements have shown ultraviolet peaks at 388nm with high intensity, which are comparable to those found in high quality ZnO films. The mechanism of the nanorod growth in the aqueous solution is proposed. The dependence of the ZnO nanorods on the growth parameters was also investigated. While changing the growth temperature from 60°C to 150°C, the morphology of the ZnO nanorods changed from sharp tip (needle shape) to flat tip (rod shape). These kinds of structure are useful in laser and field emission application.Singapore-MIT Alliance (SMA

Growth of ZnO Nanorods on GaN Using Aqueous Solution Method

Uniformly distributed ZnO nanorods with diameter 80-120 nm and 1-2µm long have been successfully grown at low temperatures on GaN by using the inexpensive aqueous solution method. The formation of the ZnO nanorods and the growth parameters are controlled by reactant concentration, temperature and pH. No catalyst is required. The XRD studies show that the ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane. The room temperature photoluminescence measurements have shown ultraviolet peaks at 388nm with high intensity, which are comparable to those found in high quality ZnO films. The mechanism of the nanorod growth in the aqueous solution is proposed. The dependence of the ZnO nanorods on the growth parameters was also investigated. While changing the growth temperature from 60°C to 150°C, the morphology of the ZnO nanorods changed from sharp tip with high aspect ratio to flat tip with smaller aspect ratio. These kinds of structure are useful in laser and field emission application.Singapore-MIT Alliance (SMA

Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 33 (2006): L17606, doi:10.1029/2006GL026321.Submarine hydrothermal systems are hypothesized to be a potentially important source of monomethylmercury (MMHg) to the ocean, yet the amount of MMHg in vent fluids is unknown. Here, we report total Hg and MMHg concentrations in hydrothermal vent fluids sampled from the Sea Cliff site on the Gorda Ridge. MMHg is the dominant Hg species, and levels of total Hg are enhanced slightly compared to seawater. Hg is enriched in deposits surrounding the site, suggesting near-field deposition from fluid plumes, with rapid MMHg demethylation and scavenging of Hg(II) complexes. Assuming the flux of MMHg from Sea Cliff is representative of global submarine hydrothermal inputs, we estimate a flux of 0.1–0.4 Mmoles y−1, which may be attenuated by scavenging near the vents. However, deep waters are not typically known to be elevated in Hg, and thus we suggest that hydrothermal systems are not significant sources of MMHg to commercial fisheries.WHOI Academic Programs Office, the Penzance Endowed Discretionary Fund, NSF-OCE and EPA-STAR, NOAA-NUR

Curb valve flow meter for gas theft detection.

As the supply of natural gas continues to dwindle, and government decontrol of pricing progresses, the rising cost of this essential natural resource will drive more individuals to consider various forms of pilferage as a way of reducing their financial burden. Today, according to numerous gas utilities, significant revenues are being lost via theft of service, losses which are ultimately passed on to the businesses' honest customers.A method to detect such thievery developed at the Massachusetts Institute of Technology for Consolidated Edison of New York, was the design of a secondary flow metering device. Located outside a suspected concern, and placed within the small confines of a modified valve or pipe structure, its function is to act as a cross reference for the existing positive displacement meter. The concept chosen was the phenomena of vortex shedding, a fluid oscillatory instability which is used extensively as a measuruing technique in the process control industry. Feasibility studies were carried out using a flat, non-moving bluff shedding element and a piezo-electric bimorph ceramic cantilevered behind it. Both elements were situated within a curb valve based prototype design having a test section inner diameter of one inch. As predicted, experiments demonstrate a repeatable, linear relationship between frequency of oscillation and volume flow for flow rates between 200 and 1000 CFH. A requirement of less than one inch of water column pressure drop across the test section was also achieved. The output signal of the bimorph varied from millivolts to several volts throughout the same specified flow range. In addition, the oscillations may be simply counted to yield and integration of the total volume delivered.The success of the concept suggests that a Phase II program, in which the laboratory design is incorporated into a device suitable for rigorous field tests by the utility, should be pursued

Analysing Systems Interdependencies Using a Digital Twin

This work provides a first step towards next-generation systems engineering by demonstrating the feasibility of using a digital twin to generate new insight into systems relationships and interdependencies. This step required substantial interdisciplinary work and industry collaboration in order to examine the potential to combine a set of relevant analytical methods (e.g. BIM query, network analyses and multi-modelling). We assembled an experienced team (Imperial College London, University of Sheffield, Newcastle University), and worked closely with and used empirical data from a major project (Thames Tideway Tunnel). This first step delivers fundamental theoretical understanding that will support the use of the digital twin for systems analyses, and a practical contribution to the identification, prioritisation and management of interdependencies. The long-term ambition is to build the tools that decision makers need in order to understand infrastructure system interdependencies within and across project boundaries

Cyber-Physical Systems Design: Formal Foundations, Methods and Integrated Tool Chains

The engineering of dependable cyber-physical systems (CPSs) is inherently collaborative, demanding cooperation between diverse disciplines. A goal of current research is the development of integrated tool chains for model-based CPS design that support co-modelling, analysis, co-simulation, testing and implementation. We discuss the role of formal methods in addressing three key aspects of this goal: providing reasoning support for semantically heterogeneous models, managing the complexity and scale of design space exploration, and supporting traceability and provenance in the CPS design set. We briefly outline an approach to the development of such a tool chain based on existing tools and discuss ongoing challenges and open research questions in this area