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Articles 1 - 10 of 10
Full-Text Articles in Environmental Engineering
Revitalizing Turtle Creek Park, Michael Hardyway, Ethan Harm, Abbey Jacoby, Casey Stephenson
Revitalizing Turtle Creek Park, Michael Hardyway, Ethan Harm, Abbey Jacoby, Casey Stephenson
Final Reports in ENST 411: Environmental Community Projects
We current ENST 411 students, Abbey Jacoby, Michael Hardyway, Ethan Harm, and Casey Stephenson have chosen to work with Jim Knight, East Buffalo Township, the Merrill Linn Land and Waterways Conservancy, and many others in an attempt to revitalize Turtle Creek Park for a plethora of reasons. Three of us are majoring in biology, and two are majoring in environmental science, which makes much of the information and techniques relevant in Turtle Creek applicable to our courses of study. This project included heavy hands on work which allowed us students to leave a memorable and impactful influence on the Lewisburg …
Nucleation-Accumulation Mode Trade-Off In Non-Volatile Particle Emissions From A Small Non-Road Small Diesel Engine, Indranil Brahma, Odinmma John-Paul Ofili
Nucleation-Accumulation Mode Trade-Off In Non-Volatile Particle Emissions From A Small Non-Road Small Diesel Engine, Indranil Brahma, Odinmma John-Paul Ofili
Faculty Journal Articles
Small (< 8 kW) non-road engines are a significant source of pollutants such as particle number (PN) emissions. Many small non-road engines do not have diesel particulate filters (DPFs). They are so designed that air–fuel ratio (AFR) can be adjusted to control visible diesel smoke and particulate matter (PM) resulting from larger accumulation mode particles. However, the effect of AFR variation on smaller nucleation mode nanoparticle emissions is not well understood. Several studies on larger engines have reported a trade-off between smaller and larger particles. In this study, AFR was independently varied over the entire engine map of a naturally aspirated (NA) non-road small diesel engine using forced induction (FI) of externally compressed air. AFR’s ranged from 57 to 239 compared to the design range of 23–92 for the engine, including unusually high AFR’s at full-load operation, not previously reported for conventional combustion. As expected, larger accumulation mode particles were lowered (up to 15 times) for FI operation. However, the smaller nucleation mode nanoparticles increased up to 15 times. Accumulation mode particles stopped decreasing above an AFR threshold while nucleation particles continuously increased. In-cylinder combustion analysis showed a slightly smaller ignition delay and higher burn rate for FI cases relative to NA operation. Much higher peak cylinder pressures were accompanied by much lower combustion and exhaust gas temperatures (EGT), due to higher in-cylinder mass during FI operation. Peak nucleation mode emissions were shown to be negatively correlated to EGT for all the data, collapsing on a single curve. This is consistent with some other studies reporting increased nucleation mode emissions (and higher accumulation mode particles) with decreased load, lower speed, lower EGR, advanced combustion phasing, and higher injection pressure, all of which reduce EGT. The nucleation-accumulation trade-off has been explained by the ‘adsorption hypothesis’ by some investigators. In the current work, an alternative/supplemental argument has been made for the possibility that lower cylinder temperatures during the late-burning phase (correlated to lower EGT) phase hampers oxidation of nucleation mode particles and increases nucleation mode emissions.
Indoor Air Quality Through The Lens Of Outdoor Atmospheric Chemistry, Jonathan P.D. Abbatt, Douglas B. Collins
Indoor Air Quality Through The Lens Of Outdoor Atmospheric Chemistry, Jonathan P.D. Abbatt, Douglas B. Collins
Faculty Contributions to Books
Outdoor atmospheric chemistry and air quality have been the topic of research that intensified in earnest around the mid-20th century, while indoor air quality research has only been a key focus of chemical researchers over the last 30 years. Examining practices and approaches employed in the outdoor atmospheric chemistry research enterprise provides an additional viewpoint from which we can chart new paths to increase scientific understanding of indoor chemistry. This chapter explores our understanding of primary chemical sources, homogeneous and multiphase reactivity, gas-surface partitioning, and the coupling between the chemistry and dynamics of indoor air through the lens of …
Unintended Consequences Of Air Cleaning Chemistry, Douglas B. Collins, Delphine K. Farmer
Unintended Consequences Of Air Cleaning Chemistry, Douglas B. Collins, Delphine K. Farmer
Faculty Journal Articles
Amplified interest in maintaining clean indoor air associated with the airborne transmission risks of SARS-CoV-2 have led to an expansion in the market for commercially available air cleaning systems. While the optimal way to mitigate indoor air pollutants or contaminants is to control (remove) the source, air cleaners are a tool for use when absolute source control is not possible. Interventions for indoor air quality management include physical removal of pollutants through ventilation or collection on filters and sorbent materials, along with chemically reactive processes that transform pollutants or seek to deactivate biological entities. This perspective intends to highlight the …
Surface Reservoirs Dominate Dynamic Gas-Surface Partitioning Of Many Indoor Air Constituents, Chen Wang, Douglas B. Collins, Caleb Arata, Allen H. Goldstein, James M. Mattila, Delphine K. Farmer, Laura Ampollini, Peter F. Decarlo, Atila Novoselac, Marina E. Vance, William W. Nazaroff, Jonathan P.D. Abbatt
Surface Reservoirs Dominate Dynamic Gas-Surface Partitioning Of Many Indoor Air Constituents, Chen Wang, Douglas B. Collins, Caleb Arata, Allen H. Goldstein, James M. Mattila, Delphine K. Farmer, Laura Ampollini, Peter F. Decarlo, Atila Novoselac, Marina E. Vance, William W. Nazaroff, Jonathan P.D. Abbatt
Faculty Journal Articles
Human health is affected by indoor air quality. One distinctive aspect of the indoor environment is its very large surface area that acts as a poorly characterized sink and source of gas-phase chemicals. In this work, air-surface interactions of 19 common indoor air contaminants with diverse properties and sources were monitored in a house using fast-response, on-line mass spectrometric and spectroscopic methods. Enhanced-ventilation experiments demonstrate that most of the contaminants reside in the surface reservoirs and not, as expected, in the gas phase. They participate in rapid air-surface partitioning that is much faster than air exchange. Phase distribution calculations are …
Restricted Salt Diffusion In A Geosynthetic Clay Liner, Michael A. Malusis, Jong Beom Kang, Charles D. Shackelford
Restricted Salt Diffusion In A Geosynthetic Clay Liner, Michael A. Malusis, Jong Beom Kang, Charles D. Shackelford
Faculty Journal Articles
No abstract provided.
Membrane Efficiency Of A Dense Prehydrated Gcl, Michael A. Malusis, Akmal Daniyarov
Membrane Efficiency Of A Dense Prehydrated Gcl, Michael A. Malusis, Akmal Daniyarov
Other Faculty Research and Publications
No abstract provided.
Chemical Compatibility Of Model Soil-Bentonite Backfill Containing Multiswellable Bentonite, Michael A. Malusis, Matthew D. Mckeehan
Chemical Compatibility Of Model Soil-Bentonite Backfill Containing Multiswellable Bentonite, Michael A. Malusis, Matthew D. Mckeehan
Faculty Journal Articles
The objective of this study was to evaluate the chemical compatibility of model soil-bentonite backfills containing multiswellable bentonite (MSB) relative to that of similar backfills containing untreated sodium (Na) bentonite or a commercially available, contaminant resistant bentonite (SW101). Flexible-wall tests were conducted on consolidated backfill specimens (effective stress =34.5 kPa) containing clean sand and 4.5–5.7% bentonite (by dry weight) using tap water and calcium chloride (CaCl2) solutions (10–1,000 mM) as the permeant liquids. Final values of hydraulic conductivity (k) and intrinsic permeability (K) to the CaCl2 solutions were determined after achieving both short-term termination criteria as …
Compressibility And Hydraulic Conductivity Of Zeolite-Amended Soil-Bentonite Backfills, Catherine Hong, Charles D. Shackelford, Michael A. Malusis
Compressibility And Hydraulic Conductivity Of Zeolite-Amended Soil-Bentonite Backfills, Catherine Hong, Charles D. Shackelford, Michael A. Malusis
Faculty Journal Articles
The effect of zeolite amendment for enhanced sorption capacity on the consolidation behavior and hydraulic conductivity, k, of a typical soil-bentonite (SB) backfill for vertical cutoff walls was evaluated via laboratory testing. The consolidation behavior and k of test specimens containing fine sand, 5.8 % (dry wt.) sodium bentonite, and 0, 2, 5, or 10 % (dry wt.) of one of three types of zeolite (clinoptilolite, chabazite-lower bed, or chabazite-upper bed) were measured using fixed-ring oedometers, and k also was measured on separate specimens using a flexible-wall permeameter. The results indicated that addition of a zeolite had little impact …
Hydraulic Conductivity Of Model Soil-Bentonite Backfills Subjected To Wet-Dry Cycling, Michael A. Malusis, Jeffrey C. Evans, Seungchoel Yeom
Hydraulic Conductivity Of Model Soil-Bentonite Backfills Subjected To Wet-Dry Cycling, Michael A. Malusis, Jeffrey C. Evans, Seungchoel Yeom
Faculty Journal Articles
The potential for changes in hydraulic conductivity, k, of two model soil-bentonite (SB) backfills subjected to wet-dry cycling was investigated. The backfills were prepared with the same base soil (clean, fine sand) but different bentonite contents (2.7 and 5.6 dry wt %). Saturation (S), volume change, and k of consolidated backfill specimens (effective stress = 24 kPa) were evaluated over three to seven cycles in which the matric suction, Ym, in the drying stage ranged from 50 to 700 kPa. Both backfills exhibited susceptibility to degradation in k caused by wet-dry cycling. Mean values of …