A Review Focusing on Aspects of Environmental Chemistry

Deutsche Forschungsgemeinschaftresearc

Community Wireless Networking and Open Spectrum Usage: a Research Agenda to Support Progressive Policy Reform of the Public Airwaves

Community Wireless Networking and Open Spectrum Usage: a Research Agenda to Support Progressive Policy Reform of the Public Airwave

Transcending Net Neutrality: Ten Steps Toward an Open Internet

The past few years have witnessed a once-obscure issue known as “net neutrality” blow up into arguably the most publicized policy debate in US telecommunications history. An untold story is how this relatively technical debate spilled outside the rarefied airs of Congressional Committees and the Federal Communications Commission’s (FCC’s) eighth floor to rage across the blogosphere, major newspapers, YouTube clips, and episodes of The Daily Show to become, if not a household phrase, a topic of popular debate involving millions of Americans. One explanation is that, at its root, the net neutrality debate is far more significant than a squabble among technocrats. Rather, it is first and foremost a normative debate, one that will determine the role of the Internet in a democratic society, with profound implications for the daily welfare of millions of citizens who rely on the Internet as a critical resource. Unfortunately, it is such normative concerns, along with related political and historical contexts, that have been least explored in much of the net neutrality scholarship to date. This article aims to address these gaps while expanding the parameters of the existing debate

New Media, Technology and Internet Use in Indian Country

The goal of this study was to gather information and develop a plan for tribes with radio stations and those without access to radio transmission facilities to use broad band media technologies to serve their communities. Since no research or data existed regarding Internet usage in Indian Country, this study sought to fill in this data gap and explore best practices and replicable models for developing broad band projects in Indian Country

Investigating the mechanism of Uranium removal by zerovalent iron

Zerovalent iron (ZVI) has been proposed as a reactive material in permeable in situ walls for groundwater contaminated by metal pollutants. For such pollutants that interact with corrosion products, the determination of the actual mechanism of their removal is very important to predict their stability in the long term. From a study of the effects of pyrite (FeS2) and manganese nodules (MnO2) on the uranium removal potential of a selected ZVI material, a test methodology (FeS2MnO2 method) is suggested to follow the pathway of contaminant removal by ZVI materials. An interpretation of the removal potential of ZVI for uranium in the presence of both additives corroborates coprecipitation with iron corrosion products as the initial removal mechanism for uranium.Keywords: iron, redox reactions, uranium, water treatmentresearc

Investigations on Iron Precipitates accumulating from underground workings and Mud Lake at South Bay

In pyritic mining wastes, the release and subsequent oxidation of Fe(II) from mining sites may produce non-negligible amounts of high sulfate and extremely low pH waters. The resulting acid mine drainage (AMD) may be divided into three types: • iron sulfide oxidation, • dissolution of soluble iron sulfate minerals, and • the dissolution of less soluble sulfate minerals of the alunite-jarosite series. The oxidation of iron sulfide minerals such as pyrite (FeS2) and pyrrhotite is responsible for the majority of acid production from mining wastes. In addition to metals, acid, sulfate is also released to ground and surface water. If sulfate is present in higher concentrations a variety of iron minerals may form, i.e.: jarosite (XFe3(SO4)2(OH)6, (X being a monovalent cation) • Schwertmannite (Fe8O8(OH)6SO4). These secondary minerals are not stable and the release of sulfate by dissolution of these minerals may result in the formation of Fe(III) hydroxides with subsequent acid (H+ ) release. Secondary mineral formation, with hydrogen-ion generation leading to pH values as low as pH 1, was reported in stored South Bay tailings pore water. Investigations on the secondary mineral phases, along with microbial investigations, were carried out and Schwertmannite minerals were detected as reported in Kalin, 2003, "The acid generation potential of iron precipitates and their sludge in Decommissioning with Ecological Engineering". This is a matter of some concern, given the high number of hydrogen ions, generated by the formation of Schwertmannite, The natural precipitation of stable, iron-hydroxide sludge, which is not a source of acidity, is an important component of the Ecological Engineering decommissioning approach. Thus Schwertmannite formation is undesirable, and the conditions under which it occurs must well understood. Samples of sludge were collected from relevant locations at the South Bay site for an investigation into the formation of this secondary mineral

Testing the Suitability of Zerovalent Iron Materials for Reactive Walls

Zerovalent iron (ZVI) has been proposed as reactive material in permeable in situ walls for contaminated groundwater. An economically feasible ZVI-based reactive wall requires cheap but efficient iron materials. From an uranium treatability study and results of iron dissolution in 0.002 M EDTA by five selected ZVI materials, it is shown that current research and field implementation is not based on a rational selection of application-specific iron metal sources. An experimental procedure is proposed which could enable a better material characterization. This procedure consists of mixing ZVI materials and reactive additives, including contaminant releasing materials (CRMs), in long-term batch experiments and characterizing the contaminant concentration over the time.Keywords: iron, redox reactions, uranium water, treatmentresearc