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Full-Text Articles in Engineering

Three-Dimensional Vapor Intrusion Modeling Approach That Combines Wind And Stack Effects On Indoor, Atmospheric, And Subsurface Domains, Elham Shirazi, Kelly G. Pennell Dec 2017

Three-Dimensional Vapor Intrusion Modeling Approach That Combines Wind And Stack Effects On Indoor, Atmospheric, And Subsurface Domains, Elham Shirazi, Kelly G. Pennell

Civil Engineering Faculty Publications

Vapor intrusion (IV) exposure risks are difficult to characterize due to the role of atmospheric, building and subsurface processes. This study presents a three-dimensional VI model that extends the common subsurface fate and transport equations to incorporate wind and stack effects on indoor air pressure, building air exchange rate (AER) and indoor contaminant concentration to improve VI exposure risk estimates. The model incorporates three modeling programs: (1) COMSOL Multiphysics to model subsurface fate and transport processes, (2) CFD0 to model atmospheric air flow around the building, and (3) CONTAM to model indoor air quality. The combined VI model predicts AER …


Performance Study On Evacuated Tubular Collector Coupled Solar Still In West Texas Climate, Roy Issa, Byungik Chang Jul 2017

Performance Study On Evacuated Tubular Collector Coupled Solar Still In West Texas Climate, Roy Issa, Byungik Chang

Civil Engineering Faculty Publications

Experimental study was performed on a single basin active solar distillation system augmented with a solar collector using evacuated solar tubes. Field tests were conducted over several days under the climatic conditions of West Texas to evaluate the effect evacuated solar tubes have on the daily distillate yield rate. To investigate the feasibility of the solar tubes, active and passive solar stills with and without exterior insulation were examined. The maximum daily production rate for the active distillation system using evacuated solar tubes and the passive distillation system was 3.6 and 1.4 kg/m2day, respectively. The results showed the …


Benefits From Constructability Reviews, Nikiforos Stamatiadis, Roy Sturgill, Kiriakos Amiridis Jun 2017

Benefits From Constructability Reviews, Nikiforos Stamatiadis, Roy Sturgill, Kiriakos Amiridis

Civil Engineering Faculty Publications

Constructability review is a process used during project design to infuse construction knowledge into the design process. There is industry impetus encouraging early construction involvement in project development. State transportation agencies often have to abide by legislation restricting these procurement methods leaving construability review as the only opportunity for early construction involvement. Staffing and budgetary constraints lead to state transportation agencies being very cautious in the practices and processes they implement that seemingly lie outside the main missions of project development and delivery. Without straightforward and documented savings of constructability review processes, these methods may also be eliminated. After streamlining …


Vulnerability Of Coastal Connecticut To Sea Level Rise: Land Inundation And Impacts To Residential Property, Rebecca Andreucci, Can B. Aktas May 2017

Vulnerability Of Coastal Connecticut To Sea Level Rise: Land Inundation And Impacts To Residential Property, Rebecca Andreucci, Can B. Aktas

Civil Engineering Faculty Publications

Vulnerability indices at the global or national scales require considerable data aggregation where local economic and social impacts remain unnoticed. The goal of this study was to analyze the extent of inundated land from sea level rise and its economic impacts to residential property in coastal communities. Geographic data were integrated with economic and social data at parcel level resolution through GIS. Cumulative land inundation in seven coastal municipalities was calculated as 15 and 25 km2, while direct economic costs to residential property was estimated to be $1.3 billion and $2.2 billion for 1 and 2 m sea …


Air Exchange Rates And Alternatuve Vapor Entry Pathways To Inform Vapor Intrusion Exposure Risk Assessments, Rivka Reichman, Mohammadyousef Roghani, Evan J. Willett, Elham Shirazi, Kelly G. Pennell Mar 2017

Air Exchange Rates And Alternatuve Vapor Entry Pathways To Inform Vapor Intrusion Exposure Risk Assessments, Rivka Reichman, Mohammadyousef Roghani, Evan J. Willett, Elham Shirazi, Kelly G. Pennell

Civil Engineering Faculty Publications

Vapor intrusion (VI) is a term used to describe indoor air (IA) contamination that occurs due to the migration of chemical vapors in the soil and groundwater. The overall vapor transport process depends on several factors such as contaminant source characteristics, subsurface conditions, building characteristics, and general site conditions. However, the classic VI conceptual model does not adequately account for the physics of airflow around and inside a building and does not account for chemical emissions from alternative “preferential” pathways (e.g. sewers and other utility connections) into IA spaces. This mini-review provides information about recent research related to building air …


Application Of Gis To Prioritize Brownfield Sites For Green Building Construction Based On Leed Criteria, Can B. Aktas, Paul Bartholomew, Sabrina Church Mar 2017

Application Of Gis To Prioritize Brownfield Sites For Green Building Construction Based On Leed Criteria, Can B. Aktas, Paul Bartholomew, Sabrina Church

Civil Engineering Faculty Publications

Although there are many initiatives to create incentives for investors and developers to invest in and redevelop brownfield sites, efficient prioritization of brownfields by taking into account environmental, economic, and social constraints remains a challenge. This study introduces a method to screen numerous brownfields over large geographic areas by using geographic information systems (GIS) and to assess and prioritize such sites for green building suitability based on leadership in energy and environmental design (LEED) criteria. A case study was completed for the greater Bridgeport, Connecticut region. With 279 brownfield sites, the city has among the highest number of brownfields in …


Life Cycle Environmental And Economic Performance Of Biochar Compared With Activated Carbon: A Meta-Analysis, Hashim A. Alhashimi, Can B. Aktas Mar 2017

Life Cycle Environmental And Economic Performance Of Biochar Compared With Activated Carbon: A Meta-Analysis, Hashim A. Alhashimi, Can B. Aktas

Civil Engineering Faculty Publications

As the commercial production and distribution of biochar continues to grow internationally, and its applications diversifying from its early uses as soil amendment, it is important to study the environmental impacts and economic performance of biochar in comparison to activated carbon in order to assess its value. The goal of the study was to assess, through a meta-analysis, the environmental and economic performance of biochar in comparison to activated carbon under an equivalent functional unit to adsorb heavy metals. More than 80 data points on adsorption capacity of biochar and activated carbon were identified through literature, which were statistically analyzed …


Heat And Water Transport In Soils And Across The Soil-Atmosphere Interface: 1. Theory And Different Model Concepts, Jan Vanderborght, Thomas Fetzer, Klaus Mosthaf, Kathleen M. Smits, Rainer Helmig Feb 2017

Heat And Water Transport In Soils And Across The Soil-Atmosphere Interface: 1. Theory And Different Model Concepts, Jan Vanderborght, Thomas Fetzer, Klaus Mosthaf, Kathleen M. Smits, Rainer Helmig

Civil Engineering Faculty Publications

Evaporation is an important component of the soil water balance. It is composed of water flow and transport processes in a porous medium that are coupled with heat fluxes and free air flow. This work provides a comprehensive review of model concepts used in different research fields to describe evaporation. Concepts range from nonisothermal two-phase flow, two-component transport in the porous medium that is coupled with one-phase flow, two-component transport in the free air flow to isothermal liquid water flow in the porous medium with upper boundary conditions defined by a potential evaporation flux when available energy and transfer to …


Heat And Water Transport In Soils And Across The Soil-Atmosphere Interface: 2. Numerical Analysis, Jan Vanderborght, Thomas Fetzer, Klaus Mosthaf, Kathleen M. Smits, Rainer Helmig Feb 2017

Heat And Water Transport In Soils And Across The Soil-Atmosphere Interface: 2. Numerical Analysis, Jan Vanderborght, Thomas Fetzer, Klaus Mosthaf, Kathleen M. Smits, Rainer Helmig

Civil Engineering Faculty Publications

In an accompanying paper, we presented an overview of a wide variety of modeling concepts, varying in complexity, used to describe evaporation from soil. Using theoretical analyses, we explained the simplifications and parameterizations in the different approaches. In this paper, we numerically evaluate the consequences of these simplifications and parameterizations. Two sets of simulations were performed. The first set investigates lateral variations in vertical fluxes, which emerge from both homogeneous and heterogeneous porous media, and their importance to capturing evaporation behavior. When evaporation decreases from parts of the heterogeneous soil surface, lateral flow and transport processes in the free flow …


Us Residential Building Air Exchange Rates: New Perspectives To Improve Decision Making At Vapor Intrusion Sites, Rivka Reichman, Elham Shirazi, Donald G. Colliver, Kelly G. Pennell Feb 2017

Us Residential Building Air Exchange Rates: New Perspectives To Improve Decision Making At Vapor Intrusion Sites, Rivka Reichman, Elham Shirazi, Donald G. Colliver, Kelly G. Pennell

Civil Engineering Faculty Publications

Vapor intrusion (VI) is well-known to be difficult to characterize because indoor air (IA) concentrations exhibit considerable temporal and spatial variability in homes throughout impacted communities. To overcome this and other limitations, most VI science has focused on subsurface processes; however there is a need to understand the role of aboveground processes, especially building operation, in the context of VI exposure risks. This tutorial review focuses on building air exchange rates (AERs) and provides a review of literature related building AERs to inform decision making at VI sites. Commonly referenced AER values used by VI regulators and practitioners do not …


Quality Improvement Of Acidic Soils By Biochar Derived From Renewable Materials, Deok Hyun Moon, Inseong Hwang, Yoon-Young Chang, Agamemnon Koutsospyros, Kyung Hoon Cheong, Won Hyun Ji, Jeong Hun Park Feb 2017

Quality Improvement Of Acidic Soils By Biochar Derived From Renewable Materials, Deok Hyun Moon, Inseong Hwang, Yoon-Young Chang, Agamemnon Koutsospyros, Kyung Hoon Cheong, Won Hyun Ji, Jeong Hun Park

Civil Engineering Faculty Publications

Biochar derived from waste plant materials and agricultural residues was used to improve the quality of an acidic soil. The acidic soil was treated for 1 month with both soy bean stover-derived biochar and oak-derived biochar in the range of 1 to 5 wt% for pH improvement and exchangeable cation enhancement. Following 1 month of treatment, the soil pH was monitored and exchangeable cations were measured. Moreover, a maize growth experiment was performed for 14 days with selected treated soil samples to confirm the effectiveness of the treatment. The results showed that the pH of the treated acidic soil increased …


System-Dynamics Modeling Of Source Mass-Depletion And Risk-Exposure Evolution For Natural Attenuation Processes In The Vadose Zone, Aspasia Kalomoiri, Agamemnon Koutsospyros, Washington Braida, Julius Pavlov Jan 2017

System-Dynamics Modeling Of Source Mass-Depletion And Risk-Exposure Evolution For Natural Attenuation Processes In The Vadose Zone, Aspasia Kalomoiri, Agamemnon Koutsospyros, Washington Braida, Julius Pavlov

Civil Engineering Faculty Publications

Public health is potentially at risk after a contaminant of concern (COC) is released into the ecosphere. The extent of contamination depends on numerous factors; modeling a contaminant’s dynamic behavior is challenging, given the multitude of relevant parameters and the fluid nature of processes involved. For example, weather events (e.g., wet or dry periods) may affect the mass depletion and the fate and transport of COCs, and hence, the risk assessment of current and potential future exposures. Thus, to give realistic estimates for potential risks, a contaminant’s dynamic behavior must be taken into account in decision-making processes. In this paper, …


Freeze-Thaw Durability Of Concrete Columns Wrapped With Frp And Subject To Corrosion-Like Expansion, Ronald S. Harichandran, M.I. Baiyasi, G. Nossoni Jan 2017

Freeze-Thaw Durability Of Concrete Columns Wrapped With Frp And Subject To Corrosion-Like Expansion, Ronald S. Harichandran, M.I. Baiyasi, G. Nossoni

Civil Engineering Faculty Publications

Experiments were conducted to assess the effects of using fiber-reinforced polymer (FRP) wraps, with fibers oriented in the hoop direction, for rehabilitating corrosion-damaged columns. This paper reports findings related to the freeze-thaw durability of concrete specimens with round and square cross sections, wrapped with glass and carbon FRP, after they are subjected to an internal expansive force similar to that generated by corroding steel. The results of the experiment indicate that freeze-thaw cycles have no statistically significant effect on the compressive strength of glass- and carbon-wrapped specimens. Freeze-thaw conditioning generally reduced the longitudinal failure strain of wrapped specimens. The square …