MEMS 411 Senior Design: Wind Powered Walking Robot

Build a ‘Machine That Walks’ using leg like linkages that is only powered by wind. It must walk a minimum of 4 meters to prove that it is capable of walking and at least half of the materials used must be recyclable or reusable within the greater St. Louis area. The machine must not exceed 10 kg and must fit in the volume of 30 cm x 60 cm x 40 cm and must be unable to be easily knocked over

The distribution and history of nuclear weapons related contamination in sediments from the Ob River, Siberia as determined by isotopic ratios of Plutonium, Neptunium, and Cesium

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2002This thesis addresses the sources and transport of nuclear weapons related contamination in the Ob River region, Siberia. In addition to being one of the largest rivers flowing into the Arctic Ocean, the bulk of the former Soviet Union's nuclear fuel reprocessing and weapons testing facilities (i.e. Mayak, Tomsk-7, and Semipalitinsk) are located within the Ob drainage basin. The atom ratios 240Pu/239Pu, 237Np/239Pu, and 13Cs/240Pu, measured by magnetic-sector ICP-MS, are used to distinguish between contamination derived from global fallout and contamination derived from local sources. Deposition chronologies estimated for sediment cores are used to construct a record of weapons related contamination at the sites sampled. Contaminant records indicate that in addition to debris from atmospheric weapons tests, materials derived from local sources have also played a role in nuclear weapons related contamination of the Ob region. Isotopic data presented in this study clearly demonstrate that non-fallout contamination has been transported the full length of the Tobol, Irysh, and Ob Rivers (i.e. the tributaries draining Mayak, Semipalitinsk, and Tomsk-7, respectively). In several instances, unique isotopic compositions are observed in sediments collected from tributaries draining each of the suspected non-fallout sources. In such cases, these materials and their deposition ages have been used to link contamination in the Ob delta to Mayak, Tomsk-7, or Semipalitinsk. Linear transport rate estimates (km yr-1) indicate that contaminated sediments transit between source tributaries and the Ob delta on time-scales of ≤ l year. These estimates suggest that a catastrophic release of contamination due to dam failure at one of the many reservoirs located at both Mayak and Tomsk-7 that contain high levels of radioactive waste would result in measurable levels of contamination in the delta within as little as 1 year. Isotopic concentrations in sequentially extracted sediments containing weapons related contamination reveal that the majority of plutonium and neptunium (80 to 90 percent) behaves in a similar fashion regardless of the source and is removed by treating the sediments with citrate-dithionite. This indicates that plutonium and neptunium are not truly refractory and likely associate with redox sensitive sedimentary components. Isotopic ratios measured in extracted fractions suggest that only a minor fraction of contamination is associated with acid leachable or acid digestible sedimentary phases.Funding for this research was provided by the Office of Naval Research under Grants N00014-93-1-1139, and NOOOI4-1-95), and the National Science Foundation under Grant EAR-98-07590

Examining Fatal Opioid Overdoses in Marion County, Indiana

Drug-related overdoses are now the leading injury-related death in the USA, and many of these deaths are associated with illicit opioids and prescription opiate pain medication. This study uses multiple sources of data to examine accidental opioid overdoses across 6 years, 2010 through 2015, in Marion County, IN, an urban jurisdiction in the USA. The primary sources of data are toxicology reports from the county coroner, which reveal that during this period, the most commonly detected opioid substance was heroin. During the study period, 918 deaths involved heroin, and there were significant increases in accidental overdose deaths involving both heroin and fentanyl. In order to disentangle the nature and source of opioid overdose deaths, we also examine data from Indiana’s prescription drug monitoring program and the law enforcement forensic services agency. Results suggest that there have been decreases in the number of opiate prescriptions dispensed and increases in law enforcement detection of both heroin and fentanyl. Consistent with recent literature, we suggest that increased regulation of prescription opiates reduced the likelihood of overdoses from these substances, but might have also had an iatrogenic effect of increasing deaths from heroin and fentanyl. We discuss several policy implications and recommendations for Indiana

Sediment Starvation Destroys New York City Marshes' Resistance to Sea Level Rise

New York City (NYC) is representative of many vulnerable coastal urban populations, infrastructures, and economies threatened by global sea level rise. The steady loss of marshes in NYC's Jamaica Bay is typical of many urban estuaries worldwide. Essential to the restoration and preservation of these key wetlands is an understanding of their sedimentation. Here we present a reconstruction of the history of mineral and organic sediment fluxes in Jamaica Bay marshes over three centuries, using a combination of density measurements and a detailed accretion model. Accretion rate is calculated using historical land use and pollution markers, through a wide variety of sediment core analyses including geochemical, isotopic, and paleobotanical analyses. We find that, since 1800 CE, urban development dramatically reduced the input of marsh stabilizing mineral sediment. However, as mineral flux decreased, organic matter flux increased. While this organic accumulation increase allowed vertical accumulation to outpace sea level, reduced mineral content causes structural weakness and edge failure. Marsh integrity now requires mineral sediment addition to both marshes and subsurface channels and borrow pits, a solution applicable to drowning estuaries worldwide. Integration of marsh mineral/organic accretion history with modeling provides parameters for marsh preservation at specific locales with sea level rise

A history of vegetation, sediment and nutrient dynamics at Tivoli North Bay, Hudson Estuary, New York

We conduct a stratigraphic paleoecological investigation at a Hudson River National Estuarine Research Reserve (HRNERR) site, Tivoli Bays, spanning the past 1100 years. Marsh sediment cores were analyzed for ecosystem changes using multiple proxies, including pollen, spores, macrofossils, charcoal, sediment bulk chemistry, and stable carbon and nitrogen isotopes. The results reveal climatic shifts such as the warm and dry Medieval Warm Period (MWP) followed by the cooler Little Ice Age (LIA), along with significant anthropogenic influence on the watershed ecosystem. A five-fold expansion of invasive species, including Typha angustifolia and Phragmites australis, is documented along with marked changes in sediment composition and nutrient input. During the last century, a ten-fold sedimentation rate increase due to land-use changes is observed. The large magnitude of shifts in vegetation, sedimentation, and nutrients during the last few centuries suggest that human activities have made the greatest impact to the marshes of the Hudson Estuary during the last millennium. Climate variability and ecosystem changes similar to those observed at other marshes in northeastern and mid-Atlantic estuaries, attest to the widespread regional signature recorded at Tivoli Bays

Integrative Acoustic Mapping Reveals Hudson River Sediment Processes and Habitats

Rivers and estuaries around the world are the focus of human settlements and activities. Needs for clean water, ecosystem preservation, commercial navigation, industrial development, and recreational access compete for the use of estuaries, and management of these resources requires a detailed understanding of estuarine morphology and sediment dynamics. This article presents an overview of the first estuary-wide study of a heavily used estuary, the Hudson River, based on high-resolution acoustic mapping of the river bottom. The integration of three high-resolution acoustic methods with extensive sampling reveals an unexpected complexity of bottom features and allows detailed classification of the benthic environment in terms of riverbed morphology, sediment type, and sedimentary processes

Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates

Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Estuarine, Coastal and Shelf Science 71 (2007): 537-544, doi:10.1016/j.ecss.2006.09.006.Sedimentary records of naturally occurring and fallout-derived radionuclides are widely used as tools for estimating both the ages of recent sediments and rates of sedimentation and bioturbation. Developing these records to the point of data interpretation requires careful sample collection, processing, analysis and data modeling. In this work, we document a number of potential pitfalls that can impact sediment core records and their interpretation. This paper is not intended as an exhaustive treatment of these potential problems. Rather, the emphasis is on potential problems that are not well documented in the literature, as follows: 1) The mere sampling of sediment cores at a resolution that is too coarse can result in an apparent diffusive mixing of the sedimentary record at rates comparable to diffusive bioturbation rates observed in many locations; 2) 210Pb profiles in slowly accumulating sediments can easily be misinterpreted to be driven by sedimentation, when in fact bioturbation is the dominant control. Multiple isotopes of different half lives and/or origin may help to distinguish between these two possible interpretations; 3) Apparent mixing can occur due simply to numerical artifacts inherent in the finite difference approximations of the advection diffusion equation used to model sedimentation and bioturbation. Model users need to be aware of this potential problem. Solutions to each of these potential pitfalls are offered to ensure the best possible sediment age estimates and/or sedimentation and bioturbation rates can be obtained.Thanks to the U.S. Geological Survey Coastal and Marine Geology Program, the Andrew F. Mellon Foundation, the Earth Institute Postdoctoral Fellowship Program at Columbia University, and the National Science Foundation for funding

Fabrication and evaluation of a micro(bio)sensor array chip for multiple parallel measurements of important cell biomarkers

© 2014 by the authors; licensee MDPI, Basel, Switzerland. This report describes the design and development of an integrated electrochemical cell culture monitoring system, based on enzyme-biosensors and chemical sensors, for monitoring indicators of mammalian cell metabolic status. MEMS technology was used to fabricate a microwell-format silicon platform including a thermometer, onto which chemical sensors (pH, O2) and screen-printed biosensors (glucose, lactate), were grafted/deposited. Microwells were formed over the fabricated sensors to give 5-well sensor strips which were interfaced with a multipotentiostat via a bespoke connector box interface. The operation of each sensor/biosensor type was examined individually, and examples of operating devices in five microwells in parallel, in either potentiometric (pH sensing) or amperometric (glucose biosensing) mode are shown. The performance characteristics of the sensors/biosensors indicate that the system could readily be applied to cell culture/toxicity studies

Genetic epidemiology of motor neuron disease-associated variants in the Scottish population

Genetic understanding of motor neuron disease (MND) has evolved greatly in the past 10 years, including the recent identification of association between MND and variants in TBK1 and NEK1. Our aim was to determine the frequency of pathogenic variants in known MND genes and to assess whether variants in TBK1 and NEK1 contribute to the burden of MND in the Scottish population. SOD1, TARDBP, OPTN, TBK1, and NEK1 were sequenced in 441 cases and 400 controls. In addition to 44 cases known to carry a C9orf72 hexanucleotide repeat expansion, we identified 31 cases and 2 controls that carried a loss-of-function or pathogenic variant. Loss-of-function variants were found in TBK1 in 3 cases and no controls and, separately, in NEK1 in 3 cases and no controls. This study provides an accurate description of the genetic epidemiology of MND in Scotland and provides support for the contribution of both TBK1 and NEK1 to MND susceptibility in the Scottish population

Trapping \u3ci\u3ePhyllophaga \u3c/i\u3espp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants.

The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester