Material Selection for an Electric Motor Assisted Stroller

The focus of this report is the process used for material selection for components of an electric motor assisted stroller designed for a senior design project. Both Solidworks’ FEA testing and CES EduPack’s materials database were utilized to gather the necessary data to evaluate both material properties and component design parameters. The initial selection process focused on gathering the necessary data and desired properties for each component system of the design. First finite element analysis was conducted on each component to find the maximum stresses encountered in operation. Then components were considered in terms of other important factors that might affect operation or the overall functionality of the system as whole. These factors include things such as corrosion resistance, environmental durability, machining cost, price, and thermal properties. All the gathered factors and data were then used to compare potential materials found using CES EduPack’s material database. A single material was then chosen for each component system and tested under FEA analysis to ensure that a satisfactory factor of safety was found

27 - Monte Carlo Simulation of a Geiger Counter, Gamma-Ray Sources and Shielding

Geiger counters are extensively utilized for measuring ionization radiation from alpha-particle, beta-particle, and gamma-ray sources. Geiger counters are used for radiation monitoring and field characterization in areas such as radiological protection, experimental physics, and nuclear industry. In this study, Monte Carlo simulations of a Geiger counter were completed using a Monte Carlo N-Particle Transport Code (MCNP). The purpose of this study was to expand the Geiger counter model to include gamma-ray shielding. To verify the code effectiveness, different simulations have been conducted using a variety of radiation sources (e.g., Cs-137 and Co-60) and materials including iron, lead, and concrete. The results are compared to the accepted general mathematical models for gamma ray shielding

The metabolic regimes of 356 rivers in the United States

A national-scale quantification of metabolic energy flow in streams and rivers can improve understanding of the temporal dynamics of in-stream activity, links between energy cycling and ecosystem services, and the effects of human activities on aquatic metabolism. The two dominant terms in aquatic metabolism, gross primary production (GPP) and aerobic respiration (ER), have recently become practical to estimate for many sites due to improved modeling approaches and the availability of requisite model inputs in public datasets. We assembled inputs from the U.S. Geological Survey and National Aeronautics and Space Administration for October 2007 to January 2017. We then ran models to estimate daily GPP, ER, and the gas exchange rate coefficient for 356 streams and rivers across the continental United States. We also gathered potential explanatory variables and spatial information for cross-referencing this dataset with other datasets of watershed characteristics. This dataset offers a first national assessment of many-day time series of metabolic rates for up to 9 years per site, with a total of 490,907 site-days of estimates.We thank Jill Baron and the USGS Powell Center for financial support for this collaborative effort (Powell Center Working Group title: "Continental-scale overview of stream primary productivity, its links to water quality, and consequences for aquatic carbon biogeochemistry"). Additional financial support came from the USGS NAWQA program and Office of Water Information. NSF grants DEB-1146283 and EF1442501 partially supported ROH. A post-doctoral grant from the Basque Government partially supported MA. NAG was supported by the U.S. Department of Energy's Office of Science, Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. Leah Colasuonno provided expert logistical support of our working group meetings. The developers of USGS ScienceBase were very helpful both in hosting this dataset and in responding to our requests. Randy Hunt and Mike Fienen of the USGS Wisconsin Modeling Center graciously provided access to their HTCondor cluster. Mike Vlah provided detailed and insightful reviews of the data and metadata

Software Carpentry: Version Control with Git

A half-day introduction to version control with Git and GitHub for researchers, developed and maintained by the Software Carpentry team