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Full-Text Articles in Engineering

The Breathing Human Infrastructure: Integrating Air Quality, Traffic, And Social Media Indicators, Heather O'Leary, Scott Parr, Marwa El-Sayed Feb 2022

The Breathing Human Infrastructure: Integrating Air Quality, Traffic, And Social Media Indicators, Heather O'Leary, Scott Parr, Marwa El-Sayed

Publications

Outdoor air pollution is a complex system that is responsible for the deaths of millions of people annually, yet the integration of interdisciplinary data necessary to assess air quality's multiple metrics is still lacking. This case study integrates atmospheric indicators (concentrations of criteria pollutants including particulate matter and gaseous pollutants), traffic indicators (permanent traffic monitoring station data), and social indicators (community responses in Twitter archives) representing the interplay of the three critical pillars of the United Nations' Triple Bottom Line: environment, economy, and society. During the watershed moment of the COVID-19 pandemic lockdowns in Florida, urban centers demonstrated the gaps …


Thermodynamic Model Of Co2 Deposition In Cold Climates, Sandra K. S. Boetcher, Ted Von Hippel, Matthew J. Traum Dec 2019

Thermodynamic Model Of Co2 Deposition In Cold Climates, Sandra K. S. Boetcher, Ted Von Hippel, Matthew J. Traum

Publications

A thermodynamic model, borrowing ideas from psychrometric principles, of a cryogenic direct-air CO2-capture system utilizing a precooler is used to estimate the optimal CO2 removal fraction to minimize energy input per tonne of CO2. Energy costs to operate the system scale almost linearly with the temperature drop between the ingested air and the cryogenic desublimation temperature of CO2, driving siting to the coldest accessible locations. System performance in three Arctic/Antarctic regions where the proposed system can potentially be located is analyzed. Colder ambient temperatures provide colder system input air temperature yielding lower CO2 removal energy requirements. A case is also …


The Effects Of Isoprene And Nox On Secondary Organic Aerosols Formed Through Reversible And Irreversible Uptake To Aerosol Water, Marwa M. El-Sayed, Diana L. Ortiz-Montalvo, Christopher J. Hennigan Jan 2018

The Effects Of Isoprene And Nox On Secondary Organic Aerosols Formed Through Reversible And Irreversible Uptake To Aerosol Water, Marwa M. El-Sayed, Diana L. Ortiz-Montalvo, Christopher J. Hennigan

Publications

Isoprene oxidation produces water-soluble organic gases capable of partitioning to aerosol liquid water. The formation of secondary organic aerosols through such aqueous pathways (aqSOA) can take place either reversibly or irreversibly; however, the split between these fractions in the atmosphere is highly uncertain. The aim of this study was to characterize the reversibility of aqSOA formed from isoprene at a location in the eastern United States under substantial influence from both anthropogenic and biogenic emissions. The reversible and irreversible uptake of water-soluble organic gases to aerosol water was characterized in Baltimore, Maryland, USA, using measurements of particulate water-soluble organic carbon …


Influence Of Activated Carbon Surface Oxygen Functionality On Elemental Mercury Adsorption From Aqueous Solution, Emily K. Faulconer, David W. Mazyck Jun 2017

Influence Of Activated Carbon Surface Oxygen Functionality On Elemental Mercury Adsorption From Aqueous Solution, Emily K. Faulconer, David W. Mazyck

Publications

Mercury (Hg), though naturally occurring, is a toxic element. Exposure to various forms of mercury can be harmful for humans and ecosystems. Mercury-contaminated wastewater can be treated using activated carbon to adsorb the mercury, allowing for safe discharge. Wet chemical oxidation of activated carbon was performed to enhanced surface oxygen functionality, with the objective of enhancing aqueous ionic (Hg(II)) and elemental (Hg(0)) mercury adsorption. Characterization of the modified carbons included nitrogen adsorption-desorption, elemental analysis, point of zero charge, and total acidity titration. The concentration and identity of the modifying reagent influenced the characteristics of the carbons, including the surface oxygen …


Direct Atmospheric Evidence For The Irreversible Formation Of Aqueous Secondary Organic Aerosol, Marwa M. El-Sayed, Yingqing Wang, Christopher J. Hennigan Jun 2015

Direct Atmospheric Evidence For The Irreversible Formation Of Aqueous Secondary Organic Aerosol, Marwa M. El-Sayed, Yingqing Wang, Christopher J. Hennigan

Publications

The reversible nature of aqueous secondary organic aerosol (aqSOA) formation was characterized for the first time through direct atmospheric measurements. Water-soluble organic carbon in the gas and particle phases (WSOCg and WSOCp) was measured simultaneously to quantify aqSOA formation in Baltimore, Maryland. During the nighttime, aqSOA formation was evident as WSOCg increasingly partitioned to the particle phase with increasing relative humidity (RH). To characterize the reversible/irreversible nature of this aqSOA, the WSOCp measurement was alternated through an unperturbed ambient channel and through a “dried” channel maintained at ~40% RH (with 7 s residence time) to mimic the natural drying particles …


The 6th Mode Of Transportation, Robert O. Walton Jan 2014

The 6th Mode Of Transportation, Robert O. Walton

Publications

The five modes of freight transportation are normally characterized as motor carriers, railroads, airlines, water carriers, and pipelines. This paper will attempt to position the Internet as the sixth mode of transportation. This paper compares the strengths and weaknesses of the traditional five modes of transportation against the proposed 6th mode of the Internet. Without including the Internet as a mode of transportation, and tracking the economic value that it adds to the economy, the economic impact of the Internet as a mode is not considered. The recommendation of this study is that the Internet should be added to the …