Superconductivity: A Breakthrough in Electrical Technology

The Environmental and Energy Study Institute (EESI) sponsored a Congressional briefing on high temperature superconductivity (HTS) technologies, which promise lower costs, less pollution, more capacity and other advantages in the transmission of an electric current. All of these advantages are crucial as electricity demand increases and the present infrastructure of wires, transformers and generating plants reaches dangerous levels of obsolescence.The burgeoning energy needs of the United States are not likely to be met by simply building more transmission lines and generating plants. According to the panel of speakers, HTS power applications, which are being tested in several U.S. locations, are expensive and must prove themselves in trials, but the future of the technology is very bright. Superconductors can carry unusually large amounts of electricity without resistance energy losses. Electric power equipment using superconductors typically have double the power capacity with only half the energy losses of the same-sized conventional counterparts. This would have a major impact in reducing the eight to ten percent of power generated that is now lost before reaching the consumer. In addition, HTS has a lower pollution potential because, among other reasons, no oil is needed for transformers and underground cables.High temperature superconductivity was initially discovered in 1986, and research and development by government and private industry has been devoted to HTS for more than 12 years. It is referred to as high temperature because the cooling necessary for HTS is at the boiling point of liquid nitrogen, which is minus 323 degrees Fahrenheit. For comparison, helium, which is used medically in magnetic resistant imaging (MRI), has a boiling point of minus 452 degrees. Because helium costs about $10 for a two-liter bottle compared to liquid nitrogen costing about 25 cents for the same size bottle, it is unrealistic to contemplate helium for "real world" generation and transmission of electricity

2001 Water Symposium: Water Pollution in Urban and Rural Settings

The Environmental and Energy Study Institute, the Federal Water Quality Association and the National Capital Chapter of the American Water Resources Association co-hosted the 2001 Water Symposium: Water Pollution In Urban And Rural Settings.The symposium examined the relative contributions of urban and rural areas to nonpoint source water pollution, and examined innovative approaches and possible synergies to improve water quality in both urban and rural portions of watersheds. Timothy L. Miller, chief of the U.S. Geological Survey's National Water Quality Assessment Program (NAWQA), outlined the major findings from 10 years of monitoring and assessing both surface and groundwater contamination in 140 rural/agricultural watersheds and more than 40 urbanized watersheds. The assessments show that water quality is affected by local land and water uses and practices, as well as population density. The urbanized study areas typically involved suburban type residential and commercial land use and low to medium population density, rather than heavily developed urban cores. Urbanized areas grew by 16 million acres between 1992 and 1995, or four to five million acres per year.For both urban and agricultural areas, nonpoint source chemical contamination is a problem. Generally such contamination was found to occur more frequently and at greater concentrations in urbanized areas, which cover less than 5 percent of the land in the continental United States, than in farming areas, which cover more than 50 percent. In both agricultural and urban settings, nutrients and pesticides were found, but the urban areas also contained volatile organics, trace metals and high insecticide concentrations. Contamination from urban areas also appeared to have a more significant detrimental influence on aquatic life. In response to a question, Miller said that arsenic exceeding the current 50 ppb (parts per billion) federal standard was found in a handful of samples, but many more exceeded the proposed 10 ppb standard

Sprawl Leaves its Footprint in Water

The Environmental and Energy Study Institute held a Congressional briefing on water pollution resulting from increased motor vehicle traffic associated with urban sprawl. The briefing featured information from recent studies by the National Water Quality Assessment Program (NAWQA) of the U.S. Geological Survey. Their studies show a consistently positive correlation between increases in vehicular traffic associated with urban sprawl and the buildup of polycyclic aromatic hydrocarbons (PAHs) in the bottom sediments of 23 lakes and reservoirs in 14 metropolitan areas around the country. NAWQA found that regulations banning or restricting substances such as DDT, lead and PCBs (polychlorinated biphenyls) has resulted in dramatic reductions of their occurrence in sediments, but the buildup of PAHs, which are not regulated, has continued to increase

Esthetic rehabilitation with ultra-thin ceramic veneers and direct mock-up in the treatment of dental erosion – Case report

Indexación: Scopus.Dental erosion is a high prevalence condition characterized by the loss of dental substance due to chemical agents. It can also be associated with �physical wear, affecting function and aesthetics. Ceramic veneers can provide effective solutions to patients affected by erosive disorders, by means of an indirect approach and minimal intervention. Recent advances in cementation techniques and ceramic materials have allowed their use in reduced thicknesses, known as "dental contact lenses" or "ultra-thin veneers". They contribute significantly to the preservation of the dental structures, having excellent models or mock ups in order to preview the final outcome. Case: The aim of this report is to communicate the use of this technique for the treatment and successful 12-months follow-up of a patient affected by dental erosion of the maxillary central incisors. Special interest was placed on direct mock-up, which is a simple technique not requiring laboratory steps. Luting of the lithium disilicate veneers was carried out with a light-curing resin cement and try-in pastes, yielding a very satisfactory result. Conclusion: Diagnosis and early treatment of this disorder allows the application of conservative techniques, such as ultra-thin veneers, which are seen as a promising alternative treatment to full coverage restorations and traditional ceramic veneers. © 2018, Universidad de Concepcion. All rights reserved.http://joralres.com/index.php/JOR/article/view/481/45

Asynchronous Discussion Groups: A Use-based Taxonomy with Examples

This paper presents a taxonomy of applications for asynchronous discussion groups as used in education. The paper begins by defining common characteristics supported by discussion board technologies: unstructured text, concurrent viewing and contribution, linear or threaded organization, and accessibility on demand. To justify the existence of distinct types of discussion boards, a variety of criteria that have been used for assessing discussion board effectiveness are presented, followed by examples of actual groups that illustrate effective use of the technologies. These examples include an analysis of the key features that distinguish discussion group uses. Based upon this analysis, the taxonomy of such groups is derived, consisting of support, participative discussion, task collaboration, workflow management and administrative. The paper concludes by identifying four prerequisites for effective discussion boards that have been synthesized from the examples and the literature--openness, efficiency, spirit of collaboration and sense of safety-showing how the relative importance of these prerequisites can depend upon the type of discussion board being examined

A Tool Also for Linguists: A Review of Paul Sullivan’s Qualitative Data Analysis Using a Dialogical Approach

Paul Sullivan (2013) introduces a method of speech analysis that uses a dialogical approach, which is distinguished from critical discourse analysis, phenomenological analysis, and grounded theory by its hermeneutic of trust. In this approach, data is analyzed using a pairing of bureaucratic and theoretical methods that indicates in the speech where the key moments are and where intonation expresses meaning. In the evaluation process subjectivity is defined and described. The types of data that would be especially suited to this approach include interviews, focus group speech, and conversation. This dialogic approach also has applications in the field of linguistic

The Memory Grid: A Glass Box View of Data Representation

Educational research has found that learning is often enhanced when the concrete is mixed with the abstract. One method of achieving this, in the context of teaching computer programming, is to provide students with a model of the activities that occur within the computer when programs are loaded and program steps are executed. Such a model is sometimes referred to as a glass box--differentiating it from a black box approach, where program activities are treated as being purely abstract in nature. The paper describes a glass box exercise developed by the author that requires students to match abstract data declarations to their concrete representation in primary storage. The exercise is used to help programming students better understand the nature of variables, arrays, and structures. Upon completing the exercise, which has proven to be popular with students in an introductory programming course, the instructor has found students are better able to apply the elegant (but initially mystifying) notations used for pointer, array and structure operations in C/C++. The paper also describes GridGen, a C++ based tool for creating such exercises and for generating online tests that can be delivered in course management environments such as Blackboard. The paper concludes with a discussion of the methodology and results that were used to evaluate the effectiveness of memory grid exercises