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2013

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Articles 91 - 120 of 201

Full-Text Articles in Environmental Engineering

Environmental And Energy Saving Technologies Of Vinyl Chloride Production, Mykola Kurta Feb 2013

Environmental And Energy Saving Technologies Of Vinyl Chloride Production, Mykola Kurta

USF Tampa Graduate Theses and Dissertations

Recently, because of the increase of environmental concerns in process design, the need to enhance conversion to product and prevent generation of wasteful byproducts in the reactor network has become urgent. This prevents high cost treatment and separation costs downstream in the process. Therefore, in this thesis I focus on making production of vinyl chloride monomer (VCM) more efficient and on possible ways of industrial organochlorine waste (OCW) recycling. In particular, in the first experiment, we investigate how catalyst and its structure can affect product output.

Infrared spectroscopy and X-ray diffraction analysis were utilized to investigate the structure of the …


Analysis Of Coal Combustion By-Products Disposal Practices At The San Juan Mine: Hydrologic And Water Quality Issues, Bruce Thomson Feb 2013

Analysis Of Coal Combustion By-Products Disposal Practices At The San Juan Mine: Hydrologic And Water Quality Issues, Bruce Thomson

Civil Engineering Faculty Publications

Coal Combustion By-Products (CCBs) are generated by the burning of coal for electric power generation and as waste streams from emissions control systems. They consist of bottom ash from the furnaces, fly ash from electrostatic precipitators, and flue gas desulfurization sludge from air pollution scrubbers. Depending on the characteristics of the coal, CCBs may contain high concentrations of metals or other constituents that present a threat to ground or surface water resources if not properly managed. This report describes results of an investigation of CCBs generated by a power plant in northwestern New Mexico. Coal Combustion By-Products from this plant …


Chemical Compatibility Of Model Soil-Bentonite Backfill Containing Multiswellable Bentonite, Michael A. Malusis, Matthew D. Mckeehan Feb 2013

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 …


Examining Consumer Behavior And Travel Choices, Kelly J. Clifton, Christopher Devlin Muhs, Sara Morrissey, Tomás Morrissey, Kristina Marie Currans, Chloe Ritter Feb 2013

Examining Consumer Behavior And Travel Choices, Kelly J. Clifton, Christopher Devlin Muhs, Sara Morrissey, Tomás Morrissey, Kristina Marie Currans, Chloe Ritter

Civil and Environmental Engineering Faculty Publications and Presentations

This study represents a first attempt to answer a few of the questions that have arisen concerning multimodal transportation investments and the impacts of mode shifts on the business community. This research aims to merge the long history of scholarly work that examines the impacts of the built environment on non-work travel with the relatively new interest in consumer spending by mode of travel. This empirical study of travel choices and consumer spending across 89 businesses in the Portland metropolitan area shows there are important differences between the amounts customers spend on average at various businesses by their mode of …


Leaching Of Metals And Metalloids From Highway Marking Glass Beads And The Potential Environmental Impact, Nimrat K. Sandhu Jan 2013

Leaching Of Metals And Metalloids From Highway Marking Glass Beads And The Potential Environmental Impact, Nimrat K. Sandhu

Dissertations

Glass beads are embedded in pavement markings to obtain retroreflectivity which plays a crucial role in the lighting-up effect needed for safe driving. Elevated metal and metalloid concentrations of As, Sb, and Pb have recently been observed in imported glass beads. The main objective of this research was to assess the environmental impact associated with applying these imported glass beads in highway markings. To achieve this objective, total metal concentrations were measured using two techniques: hydrofluoric acid digestion followed by inductively coupled plasma mass spectroscopy (HF/ICP-MS), and field portable x-ray fluorescence (FP-XRF) spectroscopy. A number of leaching studies were conducted …


Effects Of Molecular Structure Of The Oxidation Products Of Reactive Atmospheric Hydrocarbons On The Formation Of Secondary Organic Particulate Matter, Including The Effects Of Water, Negar Niakan Jan 2013

Effects Of Molecular Structure Of The Oxidation Products Of Reactive Atmospheric Hydrocarbons On The Formation Of Secondary Organic Particulate Matter, Including The Effects Of Water, Negar Niakan

Dissertations and Theses

Organic aerosols have significant effects on human health, air quality and climate. Secondary organic aerosols (SOA) are produced by the oxidation of primary-volatile organic compounds (VOC). For example, α-pinene reacts with oxidants such as hydroxyl radical (OH), ozone (O3), and nitrate radical (NO3), accounting for a significant portion of total organic aerosol in the atmosphere. Experimental studies have shown that the oxidation process between α-pinene and ozone has the most significant impact in the formation of SOA (Hoffmann et al., 1997). Most of the models used to predict SOA formation, however, are limited in that they …


2013 Nebraska Water Monitoring Programs Report, Marty Link, Joe Kenning Jan 2013

2013 Nebraska Water Monitoring Programs Report, Marty Link, Joe Kenning

Nebraska Department of Environmental Quality: Reports

The Nebraska Department of Environmental Quality (NDEQ) is charged with monitoring, assessing, and to the extent possible, managing the state’s water resources. The purpose of this work is to protect and maintain good quality water and encourage or execute activities to improve poor water quality. Monitoring is done on the over 16,000 miles of flowing rivers and streams, our greater than 148,000 acres of surface water in lakes and reservoirs, and the vast storage of groundwater in Nebraska’s aquifers.


Development Of A 2-Dimensional Finite Volume Model To Assess Hydrodynamic And Microbial Controls On Dnapl Dissolution And Detoxification, Eric S. Wesseldyke Jan 2013

Development Of A 2-Dimensional Finite Volume Model To Assess Hydrodynamic And Microbial Controls On Dnapl Dissolution And Detoxification, Eric S. Wesseldyke

Dissertations, Master's Theses and Master's Reports - Open

Tetrachloroethene (PCE) and trichloroethene (TCE) form dense non-aqueous phase liquids (DNAPLs), which are persistent groundwater contaminants. DNAPL dissolution can be "bioenhanced" via dissolved contaminant biodegradation at the DNAPL-water interface. This research hypothesized that: (1) competitive interactions between different dehalorespiring strains can significantly impact the bioenhancement effect, and extent of PCE dechlorination; and (2) hydrodynamics will affect the outcome of competition and the potential for bioenhancement and detoxification. A two-dimensional coupled flowtransport model was developed, with a DNAPL pool source and multiple microbial species. In the scenario presented, Dehalococcoides mccartyi 195 competes with Desulfuromonas michiganensis for the electron acceptors PCE and …


Energy Assessment Of Smithtown, New York, Allyson Murray, David J. Tonjes Jan 2013

Energy Assessment Of Smithtown, New York, Allyson Murray, David J. Tonjes

Technology & Society Faculty Publications

Energy management and carbon mitigation plans, often created to address global issues, must be implemented locally. Each specific area has its own needs and problems. For this study, we used publicly available data to create an energy assessment for the Town of Smithtown, a municipality of 116,000 people on the north shore of Long Island (New York). We found that motor vehicles consume the largest amount of energy, followed by space heating for both residential and commercial-industrial purposes. Local policies probably can only modestly affect transportation energy use, although federal policies may have significant effects over the next several decades. …


Social/Physical Impacts And Water Consumption Characteristics Of South Dakota’S Rural Water Systems, Matt Pajl, Delvin E. Deboer Jan 2013

Social/Physical Impacts And Water Consumption Characteristics Of South Dakota’S Rural Water Systems, Matt Pajl, Delvin E. Deboer

Water and Environmental Engineering Research Reports

This study investigates the social and physical impacts that rural water systems have on South Dakota’s population and the water consumption characteristics of city, country dwelling, and farm customer classifications. The physical characteristics of South Dakota’s rural water systems along with the 2006 water production and sales information were used to determine and relate the unique distribution characteristics and water consumption demands of the rural water systems. The impact of improved water quality to the customers of the rural water systems was shown in improved livestock production and health, customer softening salt savings, and reduction of total dissolved solids entering …


Gis And Introductory Environmental Engineering: A Way To Fold Gis Into An Already-Existing Course, Mary P. Cardenas, David Wayne Kelley, Warren Roberts Jan 2013

Gis And Introductory Environmental Engineering: A Way To Fold Gis Into An Already-Existing Course, Mary P. Cardenas, David Wayne Kelley, Warren Roberts

All HMC Faculty Publications and Research

The use of Geographical Information Systems (GIS) was implemented in the upper-division undergraduate technical elective Introduction to Environmental Engineering at Harvey Mudd College. Students integrated technical engineering skills, newly-learned geographical information system (GIS) skills, and the engineering design process, all in the context of the design of a debris flow barrier for a wilderness land parcel acquired by a local conservancy group.

Junior and senior general engineering students, the majority of whom had no experience with GIS, were taught ArcGIS (a GIS mapping program) in the context of an Introductory Environmental Engineering course. Students learned how to map locations, find …


Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson Jan 2013

Transient And Quasi-Steady Thermal Behaviour Of A Building Envelope Due To Retrofitted Cavity Wall And Ceiling Insulation, Aimee Byrne, Gerard Byrne, Anna Davies, Anthony Robinson

Articles

Accurate understanding of the thermal behaviour of building components is essential for predicting heat-ing or cooling needs and facilitates the implementation of more successful energy saving strategies and retrofits. This paper focuses on a specific measure commonly introduced through the residential energy efficiency retrofit programmes in Ireland–insulation. Traditionally, assessments of the performance of building envelopes have been based on assumed thermal resistances of the materials involved, labora-tory tests and computer modelling. The aim of the present work is to investigate the in situ thermal behaviour of a case study building and its components under transient and quasi-steady environmental conditions, comparing …


Effects Of Storage Tank Mixing On Water Quality, Andy Lemke, Delvin E. Deboer Jan 2013

Effects Of Storage Tank Mixing On Water Quality, Andy Lemke, Delvin E. Deboer

Water and Environmental Engineering Research Reports

Storage tanks are used by water systems to maintain pressure in the distribution system and to meet the varying water demands of the system. The design and operation of the storage tanks affect their mixing characteristics which affect the water quality. Poor mixing can lead to stratification in the tanks, which can lead to low chlorine residual causing microbial growth and nitrification. This thesis presents the results of the study of seven storage tanks used in South Dakota’s rural water systems. The tanks were chosen to represent varying height to diameter ratios, varying types of disinfectant, and to study passive …


Cost Effectiveness Of Recycling: A Systems Model, David J. Tonjes, Sreekanth Mallikarjun Jan 2013

Cost Effectiveness Of Recycling: A Systems Model, David J. Tonjes, Sreekanth Mallikarjun

Technology & Society Faculty Publications

Financial analytical models of waste management systems have often found that recycling costs exceed direct benefits, and in order to economically justify recycling activities, externalities such as household expenses or environmental impacts must be invoked. Certain more empirically based studies have also found that recycling is more expensive than disposal. Other work, both through models and surveys, have found differently. Here we present an empirical systems model, largely drawn from a suburban Long Island municipality. The model accounts for changes in distribution of effort as recycling tonnages displace disposal tonnages, and the seven different cases examined all show that curbside …


The John Zink Hamworthy Combustion Handbook, 2nd Edition, Volume 1: Fundamentals, Edited By Charles E. Baukal, Jr., Crc Press, Boca Raton, Fl, 2013., Payal A. Chandan Jan 2013

The John Zink Hamworthy Combustion Handbook, 2nd Edition, Volume 1: Fundamentals, Edited By Charles E. Baukal, Jr., Crc Press, Boca Raton, Fl, 2013., Payal A. Chandan

Coal Combustion and Gasification Products Journal Archive

No abstract provided.


A Community-Engagement-Based Design Project In Introductory Environmental Engineering, Mary P. Cardenas Jan 2013

A Community-Engagement-Based Design Project In Introductory Environmental Engineering, Mary P. Cardenas

All HMC Faculty Publications and Research

A collaborative, community-based design project was implemented in the upper-division undergraduate technical elective Introduction to Environmental Engineering at Harvey Mudd College. Students worked with multiple stakeholders in order to design a debris flow barrier for a wilderness land parcel acquired by a local conservancy group. The Rosemont Preserve is a wilderness area preserved in 2012 by the Arroyos and Foothills Conservancy.

The Conservancy is working to steward the land and to produce programs for the local community. The ecological resource is co-managed by LA County Public Works. After the 2009 brushfires, the County installed concrete K-Rail barriers to protect residential …


Evapotranspiration And Surface Energy Balance Of A Common Reed-Dominated Riparian System In The Platte River Basin, Central Nebraska, Isa Kabenge, Suat Irmak, John E. Gilley, George E. Meyer, Stevan Z. Knezevic, Timothy J. Arkebauer, Duane Woodward, Milton Moravek Jan 2013

Evapotranspiration And Surface Energy Balance Of A Common Reed-Dominated Riparian System In The Platte River Basin, Central Nebraska, Isa Kabenge, Suat Irmak, John E. Gilley, George E. Meyer, Stevan Z. Knezevic, Timothy J. Arkebauer, Duane Woodward, Milton Moravek

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Quantifying actual evapotranspiration (ETa) of riparian zones is important for more robust water balance analyses that will enable better planning, managing, and allocating of water resources as well as developing strategies to protect delicate riparian ecosystem functions. The ETa, sensible heat flux (H), net radiation (Rn), soil heat flux (G), meteorological variables (air temperature, Ta; incoming shortwave radiation, Rs; wind speed, u3; relative humidity, RH; vapor pressure deficit, VPD; precipitation, etc.), and albedo were measured on an hourly time step, and leaf area index (LAI) and plant height …


Evaluating Chemical Toxicity: A Novel Behavioral Assay Using Daphnia, Maya A. Zein Jan 2013

Evaluating Chemical Toxicity: A Novel Behavioral Assay Using Daphnia, Maya A. Zein

Wayne State University Dissertations

Pharmaceuticals, and personal care products (PPCPs), and other emerging contaminants, such as pesticides, are increasingly being detected in the environment. Important sources of these contaminants are waste water treatment plants and agriculture. Many of these contaminants are biologically active at low concentrations, and may impair physiological processes in exposed organisms, alter reproductive, endocrine or immune system function, and ultimately affect fitness and survival. These chemicals are often found in the environment as complex mixtures, and this complicates their evaluation of their toxicity. There is a need for high-throughput assays to rapidly assess the toxicity of these emerging contaminants. A behavioral …


Evaluation Of Non-Stationarity In Annual Maximum Flood Series Of Moderately Impaired Watersheds In The Upper Midwest And Northeastern United States, Neila Salvadori Jan 2013

Evaluation Of Non-Stationarity In Annual Maximum Flood Series Of Moderately Impaired Watersheds In The Upper Midwest And Northeastern United States, Neila Salvadori

Dissertations, Master's Theses and Master's Reports - Open

United States federal agencies assess flood risk using Bulletin 17B procedures which assume annual maximum flood series are stationary. This represents a significant limitation of current flood frequency models as the flood distribution is thereby assumed to be unaffected by trends or periodicity of atmospheric/climatic variables and/or anthropogenic activities. The validity of this assumption is at the core of this thesis, which aims to improve understanding of the forms and potential causes of non-stationarity in flood series for moderately impaired watersheds in the Upper Midwest and Northeastern US. Prior studies investigated non-stationarity in flood series for unimpaired watersheds; however, as …


Post-Project Assessment Of Pit Latrines In Rural Panama, Jacob B. Midkiff Jan 2013

Post-Project Assessment Of Pit Latrines In Rural Panama, Jacob B. Midkiff

Dissertations, Master's Theses and Master's Reports - Open

In Panama, one of the Environmental Health (EH) Sector’s primary goals is to improve the health of rural Panamanians by helping them to adopt behaviors and practices that improve access to and use of sanitation systems. In complying with this goal, the EH sector has used participatory development models to improve hygiene and increase access to latrines through volunteer managed latrine construction projects. Unfortunately, there is little understanding of the long term sustainability of these interventions after the volunteers have completed their service. With the Peace Corps adapting their Monitoring, Reporting, and Evaluation procedures, it is appropriate to evaluate the …


Resilience Quantification And Its Application To A Residential Building Subject To Hurricane Winds, Berna E. Tokgoz, Adrian V. Gheorghe Jan 2013

Resilience Quantification And Its Application To A Residential Building Subject To Hurricane Winds, Berna E. Tokgoz, Adrian V. Gheorghe

Engineering Management & Systems Engineering Faculty Publications

In order to overcome negative consequences of a disaster, buildings and infrastructures need to be resilient. After a disaster occurs, they must get back to their normal operations as quickly as possible. Buildings and infrastructures should incorporate both pre-event (preparedness and mitigation) and post-event (response and recovery) resilience activities to minimize negative effects of a disaster. Quantitative approaches for measuring resilience for buildings and infrastructures need to be developed. A proposed methodology for quantification of resilience of a given building type based on different hurricane categories is presented. The formulation for the resilience quantification is based on a model embedding …


Ozone And Gac Treatment Of A Central Florida Groundwater For Sulfide And Disinfectant By-Product Control, Tara Lamoureux Jan 2013

Ozone And Gac Treatment Of A Central Florida Groundwater For Sulfide And Disinfectant By-Product Control, Tara Lamoureux

Electronic Theses and Dissertations

This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) …


Regional Integration Of Renewable Energy Systems In Ireland: The Role Of Hybrid Energy Systems For Small Communities, Craig Goodbody, Eileen Walsh, Kevin Mcdonnell, Philip Owende Jan 2013

Regional Integration Of Renewable Energy Systems In Ireland: The Role Of Hybrid Energy Systems For Small Communities, Craig Goodbody, Eileen Walsh, Kevin Mcdonnell, Philip Owende

Articles

Due to a lack of indigenous fossil energy resources, Ireland’s energy supply constantly teeters on the brink of political, geopolitical, and geographical unease. The potential risk to the security of the energy supply combined with the contribution of anthropogenic greenhouse gas emissions to climate change gives a clear indication of Ireland's need to reduce dependency on imported fossil fuels as primary energy source. A feasibility analysis to investigate the available renewable energy options was conducted using HOMER software. The Net Present Cost, the Cost of Energy, and the CO2 emissions of each potential energy combination were considered in determining the …


Location Of Cerium In Coal-Combustion Fly Ashes: Implications For Recovery Of Lanthanides, James C. Hower, John G. Groppo, Prakash Joshi, Shifeng Dai, David P. Moecher, Michelle N. Johnston Jan 2013

Location Of Cerium In Coal-Combustion Fly Ashes: Implications For Recovery Of Lanthanides, James C. Hower, John G. Groppo, Prakash Joshi, Shifeng Dai, David P. Moecher, Michelle N. Johnston

Coal Combustion and Gasification Products Journal Archive

Given the worldwide demand for rare earth elements (REEs) in modern electronics, all potential sources of the REEs should be investigated. Coal-combustion fly ash represents a potential source of REEs. Fly ashes, derived from the combustion of coals from Kentucky in the United States and Jungar in China, were examined by wavelength-dispersive spectrometry electron microprobe analysis of epoxy-bound polished pellets. From previous studies, it was known that the REEs did not show any enrichment relative to flue gas temperature at the point of collection or to the particle size, that is, external surface area, of the particles. Cerium, the most …


Chemical Partitioning And Mobility Of Trace Elements In Dry Disposed Weathered Ash Conditioned With High-Saline Effluents, S.A. Akinyemi, A. Akinlua, W.M. Gitari, R.O. Akinyeye, L.F. Petrik Jan 2013

Chemical Partitioning And Mobility Of Trace Elements In Dry Disposed Weathered Ash Conditioned With High-Saline Effluents, S.A. Akinyemi, A. Akinlua, W.M. Gitari, R.O. Akinyeye, L.F. Petrik

Coal Combustion and Gasification Products Journal Archive

Weinvestigated the mobility of inorganic elements in the ash dump due to chemical interaction of weathered dry disposed ash conditioned with high-saline effluents and ingressed CO2 from atmosphere and percolating rainwater. Drilled ash core samples collected from dry disposed ash dump at a South African coal-burning power station were characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses. A modified sequential extraction procedure was selected to determine the mineralogical association of the investigated elements in the 1-year-old drilled ash cores. Major mineral phases are quartz and mullite and other minor phases included hematite, lime, calcite, anorthite, mica, and enstatite. …


Effects Of Coal Combustion By-Product–Encapsulated Ammonium Nitrate On Wheat Yield And Uptake Of Nitrogen And Metals, Eton E. Codling Jan 2013

Effects Of Coal Combustion By-Product–Encapsulated Ammonium Nitrate On Wheat Yield And Uptake Of Nitrogen And Metals, Eton E. Codling

Coal Combustion and Gasification Products Journal Archive

Ammonium nitrate (AN) is an essential plant nutrient for plant growth. Ammonium nitrate is also an ingredient in explosives. Research is being conducted on reducing the explosiveness of AN by encapsulating it with the use of coal by-products. The objective of this greenhouse pot study was to determine the effects of class C and F fly ash and flue gas desulfurization-gypsum-encapsulated AN on biomass, grain, and straw yield and nitrogen and metals uptake by wheat. Encapsulated AN was mixed with a low-nitrogen soil at 56 and 112 kg N ha^-1^, as well as unencapsulated AN as a control, and planted …


Geotechnical Characterization Of Clinker-Stabilized Fly Ash–Coal Mine Overburden Mixes For Subbase Of Mine Haul Road, Soumya Ranjan Mallick, Manoj Kumar Mishra Jan 2013

Geotechnical Characterization Of Clinker-Stabilized Fly Ash–Coal Mine Overburden Mixes For Subbase Of Mine Haul Road, Soumya Ranjan Mallick, Manoj Kumar Mishra

Coal Combustion and Gasification Products Journal Archive

Fly ash is a major by-product of thermal power plants that adversely affects land, water, and air. Its gainful utilization in many areas is being continuously explored. Use of fly ash in opencast coal mine haul road construction is one such option. This article reports detailed laboratory investigations carried out on clinker-stabilized fly ash–mine overburden mixes to evaluate their suitability for subbase of mine haul roads. Composite materials were prepared from fly ash, mine overburden, and clinker at different proportions. Proctor compaction test, unconfined compressive strength (UCS), and ultrasonic pulse velocity tests were carried out at different curing periods. UCS …


Variability Of Extreme Precipitation In Coastal River Basins Of The Southern Mexican Pacific Region, Nancy Perez-Morga, Thomas Kretzschmar, Tereza Cavazos, Stephen V. Smith, Francisco Munoz-Arriola Jan 2013

Variability Of Extreme Precipitation In Coastal River Basins Of The Southern Mexican Pacific Region, Nancy Perez-Morga, Thomas Kretzschmar, Tereza Cavazos, Stephen V. Smith, Francisco Munoz-Arriola

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Extreme wet and dry years (± 1 standard deviation, respectively), as well as the top 95 percentile (P95) of daily precipitation events, derived from tropical cyclone (TC) and nontropical cyclone (NTC) rainfall, were analyzed in coastal river basins in Southern Oaxaca, Mexico (Río Verde, Río Tehuantepec, and the Southern Coast). The study is based on daily precipitation records from 47 quality-controlled stations for the 1961 to 1990 period and TC data for the Eastern Tropical Pacific (EPAC). The aim of this study was to evaluate extreme (dry and wet) trends in the annual contribution of daily P95 precipitation events and …


A Note On The Occurrence Of Yttrium And Rare Earth Elements In Coal Combustion Products, James C. Hower, Shifeng Dai, Vladimir V. Seredin, Lei Zhao, Irena J. Kostova, Luis F.O. Silva, Sarah M. Mardon, Gulbin Gurdal Jan 2013

A Note On The Occurrence Of Yttrium And Rare Earth Elements In Coal Combustion Products, James C. Hower, Shifeng Dai, Vladimir V. Seredin, Lei Zhao, Irena J. Kostova, Luis F.O. Silva, Sarah M. Mardon, Gulbin Gurdal

Coal Combustion and Gasification Products Journal Archive

There is an international need for a variety of lanthanide elements (rare earth elements, or REEs) in modern electronic and related components. This has led to a desire to broaden production from both previously productive locations and to expand production to new sources, possibly including coal-derived fly ash. The concentration of lanthanides in coal-combustion fly ash depends on a number of factors, one of the most important being the concentration of the elements in the feed coal. Unlike some elements, such as Zn and As, the REE concentration is largely not a function of element volatility. In this study, we …


Fouling Intensity Of Three Indian Coals, S. Balakrishnan, R. Nagarajan Jan 2013

Fouling Intensity Of Three Indian Coals, S. Balakrishnan, R. Nagarajan

Coal Combustion and Gasification Products Journal Archive

Ash particles can arrive at heat-transfer surfaces either in solid (solidified) state or in molten state, depending on the factors such as location inside the boiler, temperature, and residence time. In this study, arrival of ash particles in solid state, which can occur in the convective section of the boiler, was considered. Apart from the inertial force that drives particles .10 mmto the surface, the low-melting inorganic alkali vapors play a vital role in deposit formation by promoting sticking. Chemical equilibrium calculations were performed to calculate the equilibrium composition of flue gas, as well as the amount of condensable inorganic …