Physical Sciences and Mathematics Commons^™

Software Development For Home Energy Audits: Reducing Energy Consumption In Harrisonburg Through Technology, Brantley E. Gilbert

Senior Honors Projects, 2010-2019

Fossil fuels play a vital role in our daily lives. Oil, natural gas, and coal powers our cars, heats our homes and water, and are used by power companies to generate the massive amounts of electricity used every day by the United States. However, this reliance on a finite source of energy is not sustainable. Fossil fuels such as these are non-renewable resources whose production will eventually be unable to keep up with the rate of consumption. Furthermore, the extraction of the stored energy in these fuels through combustion releases harmful substances into the environment, including toxins and greenhouse gases …

Marginal Structural Models: An Application To Incarceration And Marriage During Young Adulthood, Valerio Bacak, Edward Kennedy

Edward H. Kennedy

Advanced methods for panel data analysis are commonly used in research on family life and relationships, but the fundamental issue of simultaneous time-dependent confounding and mediation has received little attention. In this article the authors introduce inverse-probability-weighted estimation of marginal structural models, an approach to causal analysis that (unlike conventional regression modeling) appropriately adjusts for confounding variables on the causal pathway linking the treatment with the outcome. They discuss the need for marginal structural models in social science research and describe their estimation in detail. Substantively, the authors contribute to the ongoing debate on the effects of incarceration on marriage …

Potential Application Of Solid Electrolyte P11oh In Ni/Mh Batteries, C.Y Wang, J. Sun, Hua-Kun Liu, S. X. Dou, D. Macfarlace, M. Forsyth

Shi Xue Dou

No abstract provided.

Fabrication Of Chemical Sensors Using Inkjet Printing And Application To Gas Detection, Karl H. Crowley, Aoife Morrin, Malcolm R. Smyth, Anthony J. Killard, Roderick Shepherd, Marc In Het Panhuis, Gordon G. Wallace

Gordon Wallace

This work describes the fabrication of gas sensors using inkjet printing. Sensors were constructed by building up a film of sensing material, such as polyaniline, from aqueous nanoparticulate dispersions. These films were printed over patterned silver interdigitated array designs for the purposes of conductimetric analysis. Unlike screen printing or lithography, inkjet printing does not require stencils or masks, therefore allowing rapid design and prototyping. For this study, polyaniline and modified polyaniline sensors were inkjet printed and assessed for the purposes of gas sensing applications, specifically hydrogen sulfide monitoring.

Nanofiber Mats From Dna, Swnts, And Poly(Ethylene Oxide) And Their Application In Glucose Biosensors, Jun Chen, Chee O. Too, Gordon G. Wallace, Tuan A Nguyen, Violetta Misoska, Yong Liu

Gordon Wallace

Ultrafine fibers with diameters ranging from 50 to 300 nm were prepared from DNA/single-walled carbon nanotubes (SWNTs)/poly(ethylene oxide) blended dispersion. Well-defined electrospun fibers were obtained by good control of key dispersion properties related to electrospinning, such as ionic conductivity, surface tension, and viscosity. Raman spectroscopy confirmed the presence of SWNT in the resulting fibers, indicating good interaction between DNA and SWNT. The resulting fibers also exhibited electroactive behavior and could be used as an immobilization matrix for a glucose oxidase enzyme biosensor. The sensor response was linear up to 20 mM glucose with a sensitivity of 2.4 mA cm -2 …

Urban Climate And Challenges Of Tropical Cities, B E. Omogbai

Confluence Journal Environmental Studies (CJES), Kogi State University, Nigeria

This study examines the nature of urban climate, features and the challenges on the developing tropical cities in the 21st century. It argues that the use of principles of urban climate would help in providing comfortable living conditions and problem immune working environments for the inhabitants of tropical cities. The findings reveal that owing to poor environmental planning, inadequate geotechnical landscape surveys prior to the development of urban infrastructures, and non-adherence to the principles of urban climate, challenges of landscape degradation, excessive flooding of the built infrastructures, heat-island effects, and collapse of buildings have emerged. Suggested measures to avert these …

Application Of A Simple Hydrodynamic Model To Estuary Entrance Management, Errol J. Mclean, Jon B. Hinwood

Faculty of Science - Papers (Archive)

Tidal inlets which link a tidal basin to the sea via a constricted entrance are common on the south-east Australian coast. Closure, or even significant constriction, raises water levels but restricts tidal range within the basin, while open entrances provide regular and significant tidal exchange with the ocean. A rapid assessment procedure with minimal data requirements has been shown to be informative for monitoring and a useful component of any Decision Support System set up as part of a management structure. Such a system is presented in this paper. It is based on one permanent water level gauge inside the …

Development And Application Of A System For The Analysis Of Atmospheric, Water And Sediment Nitrogen And Carbon, Ann Stavert, Stephen R. Wilson, Dianne F. Jolley

Faculty of Science - Papers (Archive)

Eutrophication and climate change, key environmental concerns, are both linked to the carbon and nitrogen cycles hence the improved understanding of these cycles is essential. Currently, there is no system that simultaneously measures the fluxes of the three key gas phase products of nitrogen and carbon cycling (CO2, CH4 and N2O) in submerged ecosystems with hourly time resolution. A “Lake-in-a-box” (mesocosm) was developed in the laboratory which allowed the monitoring of key components of the carbon and nitrogen cycles within the air, water and sediments. The approach is automated, simple and time efficient and novel in its ability to examine …

Nanofiber Mats From Dna, Swnts, And Poly(Ethylene Oxide) And Their Application In Glucose Biosensors, Jun Chen, Chee O. Too, Gordon G. Wallace, Tuan A Nguyen, Violetta Misoska, Yong Liu

Faculty of Science - Papers (Archive)

Ultrafine fibers with diameters ranging from 50 to 300 nm were prepared from DNA/single-walled carbon nanotubes (SWNTs)/poly(ethylene oxide) blended dispersion. Well-defined electrospun fibers were obtained by good control of key dispersion properties related to electrospinning, such as ionic conductivity, surface tension, and viscosity. Raman spectroscopy confirmed the presence of SWNT in the resulting fibers, indicating good interaction between DNA and SWNT. The resulting fibers also exhibited electroactive behavior and could be used as an immobilization matrix for a glucose oxidase enzyme biosensor. The sensor response was linear up to 20 mM glucose with a sensitivity of 2.4 mA cm -2 …

Fabrication Of Chemical Sensors Using Inkjet Printing And Application To Gas Detection, Karl H. Crowley, Aoife Morrin, Malcolm R. Smyth, Anthony J. Killard, Roderick Shepherd, Marc In Het Panhuis, Gordon G. Wallace

Faculty of Science - Papers (Archive)

This work describes the fabrication of gas sensors using inkjet printing. Sensors were constructed by building up a film of sensing material, such as polyaniline, from aqueous nanoparticulate dispersions. These films were printed over patterned silver interdigitated array designs for the purposes of conductimetric analysis. Unlike screen printing or lithography, inkjet printing does not require stencils or masks, therefore allowing rapid design and prototyping. For this study, polyaniline and modified polyaniline sensors were inkjet printed and assessed for the purposes of gas sensing applications, specifically hydrogen sulfide monitoring.

Slides: Tribal Perspectives On Natural Resource Policy, Donald Wharton

The Future of Natural Resources Law and Policy (Summer Conference, June 6-8)

Presenter: Donald Wharton, Native American Rights Fund

16 slides

On The Properties Of Beta-Gamma Distribution, Lingji Kong, Carl Lee, J.H. Sepanski

Journal of Modern Applied Statistical Methods

A class of generalized gamma distribution called the beta-gamma distribution is proposed. Some of its properties are examined. Its shape can be reversed J-shaped, unimodal, or bimodal. Reliability and hazard functions are also derived, and applications are discussed.

Application Of Surrogate Methods For Assessing The Bioavailability Of Pahs In Sediments To A Sediment Ingesting Bivalve, Stuart L. Simpson, Victoria L. Burston, Dianne F. Jolley, Kim Chau

Faculty of Science - Papers (Archive)

The usefulness of two surrogate methods for rapidly determining the bioavailability of PAHs in hydrocarbon-contaminated marine sediments was assessed. Comparisons are made between the PAHs accumulated by the benthic bivalve, Tellina deltoidalis, and the extractable-PAHs determined using a 6-h XAD-2 resin desorption method and a 4-h gut fluid mimic (GFM) extraction method. There were significant positive relationships between PAH bioaccumulation by the bivalves and sediment PAH concentrations. These relationships were not improved by normalising the sediment PAH concentrations to the organic carbon concentration. The average percentage lipid content of the bivalves was 1.47 ± 0.22% and BSAFs for total-PAHs ranged …

Potential Application Of Solid Electrolyte P11oh In Ni/Mh Batteries, C.Y Wang, J. Sun, Hua-Kun Liu, S. X. Dou, D. Macfarlace, M. Forsyth

Faculty of Science - Papers (Archive)

No abstract provided.