306 research outputs found

    The physical and petrographic characteristics of formcoke produced experimentally from lignite and subbituminous coal

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    Formcoke was produced experimentally from a North Dakota lignite and a Wyoming subbituminous coal. The effect of initial charring tem perature (600°C or 900°C), of char grain size (less than 18 mesh, less than 35 mesh, or less than 60 mesh), of briquetting pressure (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or 10,000 psi) of binder percentage (5, 10, 15, 20 or 25 per cent), and of final carbonization heating rate (18°C/:min, 12°C/min or 6°C/min) on formcoke briquet com pressive strength was studied. A final carbonization heating rate of 6°C/min produced uniform shape briquets. Rates of 12°C/min and 18°C/min resulted in cracked and swollen formcoke briquets produced otherwise under the same condition as the briquets carbonized at 6°C/min. An increase in the briquetting pressure resulted in an increase in formcoke compressive strength. Formcoke produced from blends of less than 18 mesh:-900°C-lignite char and 10, 15, or 20 per cent binder exhibited uniform briquet shape. Blends with 5 per cent binder did not hold together once removed from the mold. Blends with 25 per cent binder produced swollen and cracked formcoke after final carbonization. The 600°C chars produced stronger formcoke than the 900°C chars. Formcoke compressive strength increased with a decrease in char grain size from less than 18 mesh to less than 35 mesh. Formcoke produced from less than 35 mesh char exhibited about the same strength as formcoke produced from less than 60 mesh char. Petrographically, the 900°C char grains appear more porous than the 600°C char grains. Grain to grain contact of the formcoke was better developed in the formcoke made with 600°C chars than formcoke made with 900°C chars. Grain to grain contact was better developed in formcoke made from 60 mesh char than formcoke made from 35 to 18 mesh char. Formcoke produced from North Dakota 600°C-lignite char exhibited compressive strengths equal to or greater than compressive strengths of formcoke produced from a Wyoming subbituminous coal. The FMC Corporation has been producing formcoke from Wyoming subbituminous coal, and because formcoke produced experimentally from low temperatures (600°C) lignite char was of equal quality to formcoke produced experimentally from Wyoming subbituminous char, large scale formcoke production from North Dakota lignite may be possible

    A clinical comparison of visual acuity between the Cardiff acuity test and the Teller acuity and Snellen acuity tests in an adult population

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    The newly introduced Cardiff Acuity Test developed at the University of Wales College, Cardiff UK was compared to the standard Snellen Acuity charts and the Teller Acuity cards. Acuity readings were obtained from 100 eyes (50 subjects) at distances of 1 meter and 3 meters. A significant difference was found between the 3 acuity tests with a greater deviation at distance (3 meters) than at near (1 meter). The Teller cards measured the highest (best) acuity level followed by the Cardiff and the Sneilen measuring the lowest (worst) acuity

    IXPE Mirror Module Assemblies

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    Expected to launch in 2021 Spring, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Astrophysics Small Explorer Mission with significant contributions from the Italian space agency (ASI). The IXPE observatory features three identical x-ray telescopes, each comprised of a 4-m-focal-length mirror module assembly (MMA, provided by NASA Marshall Space Flight Center) that focuses x rays onto a polarization-sensitive, imaging detector (contributed by ASI-funded institutions). This paper summarizes the MMAs design, fabrication, alignment and assembly, expected performance, and calibration plans

    Massless Metric Preheating

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    Can super-Hubble metric perturbations be amplified exponentially during preheating ? Yes. An analytical existence proof is provided by exploiting the conformal properties of massless inflationary models. The traditional conserved quantity \zeta is non-conserved in many regions of parameter space. We include backreaction through the homogeneous parts of the inflaton and preheating fields and discuss the role of initial conditions on the post-preheating power-spectrum. Maximum field variances are strongly underestimated if metric perturbations are ignored. We illustrate this in the case of strong self-interaction of the decay products. Without metric perturbations, preheating in this case is very inefficient. However, metric perturbations increase the maximum field variances and give alternative channels for the resonance to proceed. This implies that metric perturbations can have a large impact on calculations of relic abundances of particles produced during preheating.Comment: 8 pages, 4 colour figures. Version to appear in Phys. Rev. D. Contains substantial new analysis of the ranges of parameter space for which large changes to the inflation-produced power spectrum are expecte

    Patients' Experience of therapeutic footwear whilst living at risk of neuropathic diabetic foot ulceration: an interpretative phenomenological analysis (IPA).

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    BACKGROUND: Previous work has found that people with diabetes do not wear their therapeutic footwear as directed, but the thinking behind this behaviour is unclear. Adherence to therapeutic footwear advice must improve in order to reduce foot ulceration and amputation risk in people with diabetes and neuropathy. Therefore this study aimed to explore the psychological influences and personal experiences behind the daily footwear selection of individuals with diabetes and neuropathy. METHODS: An interpretative phenomenological analysis (IPA) approach was used to explore the understanding and experience of therapeutic footwear use in people living at risk of diabetic neuropathic foot ulceration. This study benefited from the purposive selection of a small sample of four people and used in-depth semi structured interviews because it facilitated the deep and detailed examination of personal thoughts and feelings behind footwear selection. FINDINGS: Four overlapping themes that interact to regulate footwear choice emerged from the analyses: a) Self-perception dilemma; resolving the balance of risk experienced by people with diabetes and neuropathy day to day, between choosing to wear footwear to look and feel normal and choosing footwear to protect their feet from foot ulceration; b) Reflective adaption; The modification and individualisation of a set of values about footwear usage created in the minds of people with diabetes and neuropathy; c) Adherence response; The realignment of footwear choice with personal values, to reinforce the decision not to change behaviour or bring about increased footwear adherence, with or without appearance management; d) Reality appraisal; A here and now appraisal of the personal benefit of footwear choice on emotional and physical wellbeing, with additional consideration to the preservation of therapeutic footwear. CONCLUSION: For some people living at risk of diabetic neuropathic foot ulceration, the decision whether or not to wear therapeutic footwear is driven by the individual 'here and now', risks and benefits, of footwear choice on emotional and physical well-being for a given social context

    Transoral resection of pharyngeal cancer: Summary of a National Cancer Institute Head and Neck Cancer Steering Committee Clinical Trials Planning Meeting, November 6–7, 2011, Arlington, Virginia

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    Recent advances now permit resection of many pharyngeal tumors through the open mouth, an approach that can greatly reduce the morbidity of surgical exposure. These transoral techniques are being rapidly adopted by the surgical community and hold considerable promise. On November 6–7, 2011, the National Cancer Institute sponsored a Clinical Trials Planning Meeting to address how to further investigate the use of transoral surgery, both in the good prognosis human papillomavirus (HPV)–initiated oropharyngeal cancers, and in those with HPV‐unrelated disease. The proceedings of this meeting are summarized. © 2012 Wiley Periodicals, Inc. Head Neck, 2012Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94490/1/23136_ftp.pd

    Insights into the Management of Emerging Infections: Regulating Variant Creutzfeldt-Jakob Disease Transfusion Risk in the UK and the US

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    BACKGROUND: Variant Creutzfeldt-Jakob disease (vCJD) is a human prion disease caused by infection with the agent of bovine spongiform encephalopathy. After the recognition of vCJD in the UK in 1996, many nations implemented policies intended to reduce the hypothetical risk of transfusion transmission of vCJD. This was despite the fact that no cases of transfusion transmission had yet been identified. In December 2003, however, the first case of vCJD in a recipient of blood from a vCJD-infected donor was announced. The aim of this study is to ascertain and compare the factors that influenced the motivation for and the design of regulations to prevent transfusion transmission of vCJD in the UK and US prior to the recognition of this case. METHODS AND FINDINGS: A document search was conducted to identify US and UK governmental policy statements and guidance, transcripts (or minutes when transcripts were not available) of scientific advisory committee meetings, research articles, and editorials published in medical and scientific journals on the topic of vCJD and blood transfusion transmission between March 1996 and December 2003. In addition, 40 interviews were conducted with individuals familiar with the decision-making process and/or the science involved. All documents and transcripts were coded and analyzed according to the methods and principles of grounded theory. Data showed that while resulting policies were based on the available science, social and historical factors played a major role in the motivation for and the design of regulations to protect against transfusion transmission of vCJD. First, recent experience with and collective guilt resulting from the transfusion-transmitted epidemics of HIV/AIDS in both countries served as a major, historically specific impetus for such policies. This history was brought to bear both by hemophilia activists and those charged with regulating blood products in the US and UK. Second, local specificities, such as the recall of blood products for possible vCJD contamination in the UK, contributed to a greater sense of urgency and a speedier implementation of regulations in that country. Third, while the results of scientific studies played a prominent role in the construction of regulations in both nations, this role was shaped by existing social and professional networks. In the UK, early focus on a European study implicating B-lymphocytes as the carrier of prion infectivity in blood led to the introduction of a policy that requires universal leukoreduction of blood components. In the US, early focus on an American study highlighting the ability of plasma to serve as a reservoir of prion infectivity led the FDA and its advisory panel to eschew similar measures. CONCLUSIONS: The results of this study yield three important theoretical insights that pertain to the global management of emerging infectious diseases. First, because the perception and management of disease may be shaped by previous experience with disease, especially catastrophic experience, there is always the possibility for over-management of some possible routes of transmission and relative neglect of others. Second, local specificities within a given nation may influence the temporality of decision making, which in turn may influence the choice of disease management policies. Third, a preference for science-based risk management among nations will not necessarily lead to homogeneous policies. This is because the exposure to and interpretation of scientific results depends on the existing social and professional networks within a given nation. Together, these theoretical insights provide a framework for analyzing and anticipating potential conflicts in the international management of emerging infectious diseases. In addition, this study illustrates the utility of qualitative methods in investigating research questions that are difficult to assess through quantitative means

    Complex I-Associated Hydrogen Peroxide Production Is Decreased and Electron Transport Chain Enzyme Activities Are Altered in n-3 Enriched fat-1 Mice

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    The polyunsaturated nature of n-3 fatty acids makes them prone to oxidative damage. However, it is not clear if n-3 fatty acids are simply a passive site for oxidative attack or if they also modulate mitochondrial reactive oxygen species (ROS) production. The present study used fat-1 transgenic mice, that are capable of synthesizing n-3 fatty acids, to investigate the influence of increases in n-3 fatty acids and resultant decreases in the n-6∶n-3 ratio on liver mitochondrial H2O2 production and electron transport chain (ETC) activity. There was an increase in n-3 fatty acids and a decrease in the n-6∶n-3 ratio in liver mitochondria from the fat-1 compared to control mice. This change was largely due to alterations in the fatty acid composition of phosphatidylcholine and phosphatidylethanolamine, with only a small percentage of fatty acids in cardiolipin being altered in the fat-1 animals. The lipid changes in the fat-1 mice were associated with a decrease (p<0.05) in the activity of ETC complex I and increases (p<0.05) in the activities of complexes III and IV. Mitochondrial H2O2 production with either succinate or succinate/glutamate/malate substrates was also decreased (p<0.05) in the fat-1 mice. This change in H2O2 production was due to a decrease in ROS production from ETC complex I in the fat-1 animals. These results indicate that the fatty acid changes in fat-1 liver mitochondria may at least partially oppose oxidative stress by limiting ROS production from ETC complex I

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure
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