Pinkney A.E.,U.S. Fish and Wildlife Service |
Harshbarger J.C.,George Washington University |
Karouna-Renier N.K.,U.S. Geological Survey |
Jenko K.,U.S. Geological Survey |
And 4 more authors.
Science of the Total Environment | Year: 2011
We surveyed four Chesapeake Bay tributaries for skin and liver tumors in brown bullhead (Ameiurus nebulosus). We focused on the South River, where the highest skin tumor prevalence (53%) in the Bay watershed had been reported. The objectives were to 1) compare tumor prevalence with nearby rivers (Severn and Rhode) and a more remote river (Choptank); 2) investigate associations between tumor prevalence and polynuclear aromatic hydrocarbons (PAHs) and alkylating agents; and 3) statistically analyze Chesapeake Bay bullhead tumor data from 1992 through 2008. All four South River collections exhibited high skin tumor prevalence (19% to 58%), whereas skin tumor prevalence was 2%, 10%, and 52% in the three Severn collections; 0% and 2% in the Choptank collections; and 5.6% in the Rhode collection. Liver tumor prevalence was 0% to 6% in all but one South River collection (20%) and 0% to 6% in the three other rivers. In a subset of samples, PAH-like biliary metabolites and 32P-DNA adducts were used as biomarkers of exposure and response to polycyclic aromatic compounds (PACs). Adducts from alkylating agents were detected as O6-methyl-2'-deoxyguanosine (O6Me-dG) and O6-ethyl-2'-deoxyguanosine (O6Et-dG) modified DNA. Bullheads from the contaminated Anacostia River were used as a positive control for DNA adducts. 32P-DNA adduct concentrations were significantly higher in Anacostia bullhead livers compared with the other rivers. We identified alkyl DNA adducts in bullhead livers from the South and Anacostia, but not the Choptank. Neither the PAH-like bile metabolite data, sediment PAH data, nor the DNA adduct data suggest an association between liver or skin tumor prevalence and exposure to PACs or alkylating agents in the South, Choptank, Severn, or Rhode rivers. Logistic regression analysis of the Chesapeake Bay database revealed that sex and length were significant covariates for liver tumors and length was a significant covariate for skin tumors. © 2011.
Nikhare C.P.,Penn State Erie The Behrend College |
Korkolis Y.P.,University of New Hampshire |
Kinsey B.L.,University of New Hampshire
Journal of Manufacturing Science and Engineering, Transactions of the ASME | Year: 2015
The tube flaring process has been traditionally used to expand one end of a tube without changing its cross-sectional area. This simple process typically forms the product using a single punch. To delay failure and enhance formability, a two-step flaring process can be used. For example, if a significant elliptical flared shape is attempted in a one-step process, a necking/tearing failure would occur on the major axis of the ellipse. However, if a two-step process, starting with a mildly elliptical punch and followed by the final, sharply elliptical punch is used instead, the desired elliptical shape can be achieved. In this paper, the effects of the punch geometry of the first step on the deformation paths are numerically analyzed. By manipulating the deformation path, failure can be delayed so that higher formability is achieved. The numerical model is validated by comparison with experimental results. © 2015 by ASME.
Hamasha M.M.,University of Business and Technology |
Alazzam A.,Universal Solution |
Hamasha S.,Binghamton University State University of New York |
Aqlan F.,Penn State Erie The Behrend College |
And 2 more authors.
IEEE Transactions on Components, Packaging and Manufacturing Technology | Year: 2015
In this paper, a stochastic model is developed to analyze the performance of a flexible manufacturing cell (FMC). The FMC considered in this paper consists of a single conveyor, a single robot, and one or more machine(s). The conveyor belt delivers the working part to the robot, which loads it onto the machine. A Markov chain model is constructed for one-machine and two-machine FMCs, after which the model is generalized to an FMC with n machines. Most importantly, the model provides an estimate of the overall machine utilization and production rate for the FMC under consideration and also illustrates the effect of different operational factors on machine utilization and production rate. The results indicated that the overall machine utilization increases with conveyor belt and robot delivery rates and decreases with machine rate, as expected. However, this decrease or the increase in the overall machine utilization is sharp at low levels of each parameter (e.g., conveyor belt delivery and robot loading), but it gradually stabilizes at higher levels of the parameters. Finally, the production rate increases sharply at low levels of each parameter and gradually stabilizes at higher levels. © 2015 IEEE.
Pleta A.D.,Penn State Erie The Behrend College |
Krugh M.C.,Penn State Erie The Behrend College |
Nikhare C.,Penn State Erie The Behrend College |
Roth J.T.,Penn State Erie The Behrend College
ASME 2013 International Manufacturing Science and Engineering Conference Collocated with the 41st North American Manufacturing Research Conference, MSEC 2013 | Year: 2013
Due to more stringent environmental regulations, the demand for strong, lightweight metal alloys, such as AA 5083, has increased. In sheet metal forming, aluminum is preferred over higher density steels to manufacture such parts; however the in-plane anisotropic behavior of AA 5083 alloy greatly affects its formability. Previous researchers have found that mechanical properties of metallic materials can be influenced by DC electrical current, a research area known as Electrically-Assisted Manufacturing (EAM). The research herein is focused on characterizing the in-plane anisotropic behavior of AA 5083 alloy with and without DC current application, while it is loaded in the uniaxial direction. Furthermore, the effects of EAM on Lueder's banding will also be investigated. Copyright © 2013 by ASME.
Patanakul P.,Penn State Erie The Behrend College |
Pinto J.K.,Penn State Erie The Behrend College |
Pinto M.B.,Penn State Erie The Behrend College
Journal of Engineering and Technology Management - JET-M | Year: 2016
This study was conducted to investigate the impact of autonomy, support, goal clarity, and learning opportunities on the motivation to perform of project managers and team members in multiple-project environments. Even though the motivation literature is rather extensive, the motivation of personnel in multiple-project environments is underexplored. As management of multiple projects becomes very common in industry, the understanding of what motivates project managers and team members who work on multiple, simultaneous projects is crucial. Such an understanding should guide management to create conditions that support multiple-project management, reduce burnout, and help retain project personnel. In addition, the findings from this study extend the application of motivation concepts to multiple-project management and shed light on future research opportunities. © 2016 Elsevier B.V. All rights reserved.
Champagne J.,Penn State Erie The Behrend College
Journal of Homosexuality | Year: 2014
Because works of nonfiction are always composed of literary tropes and metaphors, they have to be read critically for the ways in which their truth claims are potentially structured by ideologies and stereotypes. This essay reads passages from Richard Sennett's sociological analysis Flesh and Stone, The Body and the City in Western Civilization and Joseph Brodsky's memoir Watermark in order to demonstrate how these alleged works of nonfiction shore up some dishearteningly familiar literary stereotypes of male homosexuality and participate in a tradition, dating from the 19th century, of linking the city of Venice with homosexuality and death. Copyright © Taylor & Francis Group, LLC.
Nikhare C.P.,Penn State Erie the Behrend College |
Loker D.,Penn State Erie the Behrend College |
Conklin C.,Penn State Erie the Behrend College |
Ragai I.,Penn State Erie the Behrend College |
And 2 more authors.
ASME 2015 International Manufacturing Science and Engineering Conference, MSEC 2015 | Year: 2015
Quenching is an important part of the heat treatment process for strengthening medium and high carbon steels. In the heat treatment cycle, the metal is heated to a desired temperature (above the eutectoid temperature) in the furnace and then cooled in a fluid medium such as water, brine, oil or air. Depending on the cooling rate, the mechanical and metallurgical properties of the metal can be altered in order to achieve the specific design parameters that are required by the part. The process in which the metal is cooled rapidly is termed the quenching process. Due to rapid cooling in a medium, such as water, brine, or oil, the quenching process produces an audible sound signature, as well as, acoustic emissions. In this paper, W1 tool steel is investigated through the use of a beam former that is equipped with 32 microphones. Using this device, it is demonstrated that the audible sounds that are produced when quenching depend on the heat treatment temperature and the size of the specimen. Copyright © 2015 by ASME.
Niebauer J.,Penn State Erie The Behrend College |
Grimm T.,Penn State Erie The Behrend College |
Shaffer D.,Penn State Erie The Behrend College |
Sweeney I.,Penn State Erie The Behrend College |
And 2 more authors.
ASME 2016 11th International Manufacturing Science and Engineering Conference, MSEC 2016 | Year: 2016
One of the major issues with forming sheet metal is the tendency for parts to spring back towards their original shape when the applied loading is released. Springback is a form of geometric inaccuracy and is the result of residual stresses, which are created as the part deforms. As a result, forming intricate parts require specialized equipment and calculations to compensate for springback. Transportation industries that rely on forming high strength parts currently use complicated machinery that takes up time and energy to meet specifications. This research investigates the effects of electrically assisted manufacturing (EAM), a process in which electrical current is applied while a material is being manufactured, on springback. Bending and flattening testing will be performed on 4 metals: stainless steel 304 and 316, ASM-T-9046 titanium, and AZ31B magnesium. Additional testing will be performed on stainless steel, observing the effect of changing thicknesses, pulse durations, and current densities on springback. It was observed that an increase in pulse durations results in decreased springback for all the materials. Applying electricity to decrease springback was more effective for bending than flattening procedures in stainless steel and titanium, though it was equally effective for magnesium. For the additional testing on stainless steel, a change in thickness affected results when comparing it to current density, but not when observing similar applied current. Copyright © 2016 by ASME.
Foyle A.M.,Penn State Erie The Behrend College |
Naber M.D.,Penn State Erie The Behrend College
Environmental Earth Sciences | Year: 2012
Bluff retreat is an ongoing problem on the southern Great Lakes coast of the United States where Pleistocene unconsolidated sediments overlie Devonian bedrock. This retreat results in loss of sediment from the coastal zone and a decrease in coastal water quality, and is of concern because evaluating landslide hazards and developing regulations on coastal construction setbacks must account for spatial variability in coastal retreat. The goal of this pilot study is to explain and quantify short to medium term spatial variability in bluff-retreat patterns, magnitudes, and rates along a 6 km littoral cell on the Pennsylvania coast of Lake Erie. High-resolution LiDAR data covering a one-decade time frame (1998-2007) permit mapping of the bluff-crest position on two comparable, high-quality data sets. The rates of bluff retreat range from unresolvable (~20% of coast) to 2.2 m/year, averaging 0.22 ± 0.1 m/year. Average-annual change rates and 9-year net movement values show an along-coast periodicity, with a spatial wavelength of ~1 km and an amplitude of 0.2 m/year. Observed variability is inferred to occur because variations in surface watershed size and groundwater recharge area, topographic shielding of the bluff from overland flow, and groundwater-table topography, cause groundwater discharge and overland flow to the bluff face to vary along the coast. In addition, short ravines (< 300 m in length) fed by groundwater seepage distort groundwater equipotential lines and cause locally enhanced bluff retreat. While other factors likely influence bluff retreat spatially along this coast, their roles are relatively minor at the scale of this study. © 2011 Springer-Verlag.