Contributions to predicting contaminant leaching from secondary materials used in roads

Slags, coal ashes, and other secondary materials can be used in road construction. Both traditional and secondary materials used in roads may contain contaminants that may leach and pollute the groundwater. The goal of this research was to further the understanding of leaching and transport of contaminants from pavement materials. Towards this goal, a new probabilistic framework was introduced which provided a structured guidance for selecting the appropriate model, incorporating uncertainty, variability, and expert opinion, and interpreting results for decision making. In addition to the framework, specific contributions were made in pavement and embankment hydrology and reactive transport, Bayesian statistics, and aqueous geochemistry of leaching. Contributions on water movement and reactive transport in highways included probabilistic prediction of leaching in an embankment, and scenario analyses of leaching and transport in pavements using HYDRUS2D, a contaminant fate and transport model. Water flow in a Minnesota highway embankment was replicated by Bayesian calibration of hydrological parameters against water content data. Extent of leaching of Cd from a coal fly ash was estimated. Two dimensional simulations of various scenarios showed that salts in the base layer of pavements are depleted within the first year whereas the metals may never reach the groundwater if the pavement is built on adsorbing soils. Aqueous concentrations immediately above the groundwater estimated for intact and damaged pavements can be used for regulators to determine the acceptability of various recycled materials. Contributions in the aqueous geochemistry of leaching included a new modeling approach for leaching of anions and cations from complex matrices such as weathered steel slag. The novelty of the method was its simultaneous inclusion of sorption and solubility controls for multiple analytes. The developed model showed that leaching of SO4, Cr, As, Si, Ca, Mg, and V were controlled by corresponding soluble solids. Leaching of Pb was controlled by Pb(VO4)3 solubility at low pHs and by surface precipitation reactions at high pHs. Leaching of Cd and Zn were controlled by surface complexation and surface precipitation, respectively

What is the role of women in James Joyce’s Dubliners and Sherwood Anderson’s Winesburg, Ohio?

This extended essay is an investigation of the protagonist female characters in both James Joyce’s Dubliners and Sherwood Anderson’s Winesburg, Ohio. The research question revolves around unwed young women and married women in their motherhood in terms of man-woman relationships, sociocultural views and religious concepts. In addition to the context, the purpose and explanation of the literary devices is included in the relevant sections of the essay. The arguments are fully supported by quotations from the two literary works and refuted with proper historical knowledge in appropriate places. Mainly only the characters in the chosen short stories are analyzed and explored, however for some of the stories, additional characters are taken into consideration. The purpose of this work is to investigate how women are portrayed in two diverse cultures with the aforementioned circumstances. The extended essay is composed of an introduction, main body and conclusion. In the main body, James Joyce’s Dubliners and Sherwood Anderson’s Winesburg, Ohio is evaluated and analyzed. The two literary works are compared within their own historical and cultural context. While analyzing the short stories, a pattern of the development and growth of a woman is displayed by initially capturing a young teenage girl’s story to focusing on a married mother. Furthermore, in the comparison paragraph, the scope of the two authors and how much they depart from historical context is taken into account. In the conclusion of the essay, the roles of women in both Irish and American cultures are reflected upon and the authors’ own interpretations, thoughts and attitudes towards women are successfully revealed with their unique writing styles

Modeling the Turkish Broad Money Demand

This paper analyzes broad money demand in Turkey between 1987 and 2001, a period characterized by a process of financial sector liberalization, implemented using various structural reforms and deregulations. It presents the historical background and the pace of liberalization, accompanied by a discussion on main economic indicators. It gives a brief summary on theory for the analysis of money demand and constructs an error correction model for M2X using quarterly data, where the long run relationship is established using real income, interest rate on deposits, interest rate on government securities, inflation rate and real exchange rate. The results show that, both exchange rate and inflation rate have substantial impact on the Turkish broad money demand.Money Demand, Financial Liberalization, Cointegration, Error-correction Modeling

The lesson from the Greek crisis should be that economics exists for the good of society, not for its own sake

A Greek bailout deal has been agreed in principle between the country’s government and its creditors. Defne Gonenc writes that throughout the crisis there has been a tendency to view economics as detached from politics, with the impact of economic policies on individual citizens largely pushed to the sidelines in discussions surrounding the technicalities of a bailout deal. She argues that rather than pursuing economics for its own sake, a better approach would be to adopt a narrative that focuses on what economic solutions can do for society

Quantifying the residence time and flushing characteristics of a shallow, back-barrier estuary : application of hydrodynamic and particle tracking models

This paper is not subject to U.S. copyright. The definitive version was published in Estuaries and Coasts 38 (2015): 1719-1734, doi:10.1007/s12237-014-9885-3.Estuarine residence time is a major driver of eutrophication and water quality. Barnegat Bay-Little Egg Harbor (BB-LEH), New Jersey, is a lagoonal back-barrier estuary that is subject to anthropogenic pressures including nutrient loading, eutrophication, and subsequent declines in water quality. A combination of hydrodynamic and particle tracking modeling was used to identify the mechanisms controlling flushing, residence time, and spatial variability of particle retention. The models demonstrated a pronounced northward subtidal flow from Little Egg Inlet in the south to Pt. Pleasant Canal in the north due to frictional effects in the inlets, leading to better flushing of the southern half of the estuary and particle retention in the northern estuary. Mean residence time for BB-LEH was 13 days but spatial variability was between ∼0 and 30 days depending on the initial particle location. Mean residence time with tidal forcing alone was 24 days (spatial variability between ∼0 and 50 days); the tides were relatively inefficient in flushing the northern end of the Bay. Scenarios with successive exclusion of physical processes from the models revealed that meteorological and remote offshore forcing were stronger drivers of exchange than riverine inflow. Investigations of water quality and eutrophication should take into account spatial variability in hydrodynamics and residence time in order to better quantify the roles of nutrient loading, production, and flushing.Funding was provided by the New Jersey Department of Environmental Protection and the Coastal and Marine Geology Program of the U.S. Geological Survey

The Sardar Sarovar dam: drowning out citizens but who benefits?

The controversial damming of the Narmada river in central India goes on, even though the project has been plagued by escalating costs, corruption scandals and protests over human rights and environmental abuses. Yet despite financial, social and environmental deficiencies Defne Gonenc writes that the main beneficiaries are multinationals and large contractors, rather than the hundreds of ordinary Indians who need clean drinking water and access to the river for their livelihoods

Probabilistic modeling of one dimensional water movement and leaching from highway embankments containing secondary materials

Predictive methods for contaminant release from virgin and secondary road construction materials are important for evaluating potential long-term soil and groundwater contamination from highways. The objective of this research was to describe the field hydrology in a highway embankment and to investigate leaching under unsaturated conditions by use of a contaminant fate and transport model. The HYDRUS2D code was used to solve the Richards equation and the advection–dispersion equation with retardation. Water flow in a Minnesota highway embankment was successfully modeled in one dimension for several rain events after Bayesian calibration of the hydraulic parameters against water content data at a point 0.32 m from the surface of the embankment. The hypothetical leaching of Cadmium from coal fly ash was probabilistically simulated in a scenario where the top 0.50 m of the embankment was replaced by coal fly ash. Simulation results were compared to the percolation equation method where the solubility is multiplied by the liquid-to-solid ratio to estimate total release. If a low solubility value is used for Cadmium, the release estimates obtained using the percolation/equilibrium model are close to those predicted from HYDRUS2D simulations (10–4–10–2 mg Cd/kg ash). If high solubility is used, the percolation equation over predicts the actual release (0.1–1.0 mg Cd/kg ash). At the 90th percentile of uncertainty, the 10-year liquid-to-solid ratio for the coal fly ash embankment was 9.48 L/kg, and the fraction of precipitation that infiltrated the coal fly ash embankment was 92%. Probabilistic modeling with HYDRUS2D appears to be a promising realistic approach to predicting field hydrology and subsequent leaching in embankments

Estimating time-dependent connectivity in marine systems

This paper is not subject to U.S. copyright. The definitive version was published in Geophysical Research Letters 43 (2016): 1193–1201, doi:10.1002/2015GL066888.Hydrodynamic connectivity describes the sources and destinations of water parcels within a domain over a given time. When combined with biological models, it can be a powerful concept to explain the patterns of constituent dispersal within marine ecosystems. However, providing connectivity metrics for a given domain is a three-dimensional problem: two dimensions in space to define the sources and destinations and a time dimension to evaluate connectivity at varying temporal scales. If the time scale of interest is not predefined, then a general approach is required to describe connectivity over different time scales. For this purpose, we have introduced the concept of a “retention clock” that highlights the change in connectivity through time. Using the example of connectivity between protected areas within Barnegat Bay, New Jersey, we show that a retention clock matrix is an informative tool for multitemporal analysis of connectivity.New Jersey Department of Environmental Protectio

The work conditions of allied health professionals : the impact on satisfaction, commitment and psychological distress

The present study investigated the extent to which the Demand-Control-Support (DCS) model, in combination with organizational justice variables, predicts the employee-level outcomes of allied health professionals\u27. Allied health professionals from an Australian healthcare organization were surveyed, with 113 participating (52,6%). Multiple regression analyses revealed that the DCS model predicted all the outcome variables of job satisfaction, organizational commitment and psychological distress. Conversely, significant contributions of the organizational justice variables were limited to organizational commitment and psychological distress. The results of the study provide practical implications for the job conditions of allied health professionals, in particular, the delivery of support and maintaining high levels of justice.<br /