396 research outputs found

    Interaction of Sodium, Sulfur, and Silica during Coal Combustion

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    The Interaction of Sodium, Sulfur, and Silica at Conditions Typical in a Pulverized Coal Furnace Was Investigated by using Both Model Mixtures and a Synthetic Coal. the Model Mixtures Consisted of Selected Inorganic Constituents that Were Well Mixed in Proportions Typically Found in Low-Rank Coal. the Synthetic Coal Consisted of a Furfuryl Alcohol Polymer with Appropriate Amounts of Sodium, Sulfur, and Silica to Duplicate the Characteristics of Low-Rank Coal. the Model Mixtures and Synthetic Coal Were Burned in a Laminar Flow (Drop-Tube) Furnace at 900, 1100, 1300, and 1500 °C and Residence Times of 0.1,0.5,1.5, and 2.4 S. the Resulting Char and Fly Ash Particles Were Quickly Quenched, Collected, and Analyzed with a Scanning Electron Microscope (SEM) to Determine Size and Composition. Results Indicated that the Formation of Sodium Silicates is Favored by Higher Temperatures and Longer Residence Times. Thermodynamic Calculations and the Model Mixture Studies Indicated above 1100 °C There is Little Interference in the Formation of Sodium Silicates by Sodium Sulfates. in the Synthetic Coal Studies, Sodium Sulfate Particles Were Detected on the Surface of the Larger Sodium Silicate Fly Ash Particles Formed at Lower Temperatures. the Size and Prevalence of the Sodium Sulfate Particles Decreased as Temperature Was Increased. Fly Ash Particle Formation Was Characterized by Fragmentation Followed by Coalescence. Fragmentation Was More Prevalent at Higher Temperatures and Smaller Fly Ash Particles Were Formed. Larger Particles Were Formed at Lower Temperatures, Indicating More Complete Coalescence with Some Cenosphere Formation. © 1991, American Chemical Society. All Rights Reserved

    Out-migration: Challenges, Opportunities, and Resiliency in Rural Communities

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    The Addition of the Charlson Comorbidity Index to the GRACE Risk Prediction Index Improves Prediction of Outcomes in Acute Coronary Syndrome

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    Patients with cardiovascular disease have increased risk of poor outcomes when coexisting illnesses are present. Clinicians, administrators, and health services researchers utilize risk adjustment indices to stratify patients for various outcomes. The GRACE Risk Prediction Index (GRPI) was developed to risk stratify patients who experienced an acute coronary syndrome (ACS) event. GRPI does not account for the presence of comorbid conditions. The objective of this study was to compare the ability of the GRPI and the Charlson Comorbidity Index (CCI), used independently or combined, to predict mortality or secondary coronary events in patients admitted for ACS. Data were obtained from an academic health system's ACS registry. Outcomes included inpatient and 6-month postdischarge mortality and occurrence of secondary cardiovascular events or revascularization procedures. Logistic regression derived C statistics for CCI, GRPI, and CCI-GRPI predictive models for each outcome. Likelihood ratio tests determined the contribution of CCI when added to GRPI models. Complete data were available for 1202 patients. The GRPI model had the greatest C statistic when predicting inpatient mortality (0.73); the GRPI-CCI combined model C statistic was 0.81 when predicting death during the follow-up period; and C statistics for all 3 models were similar in predicting secondary events (0.57?0.60). The likelihood ratio analysis demonstrated that adding CCI to GRPI models was beneficial primarily for predicting secondary events. CCI is a useful addition to GRPI when predicting future cardiac-related events or mortality after an ACS event. It is an acceptable alternative to the GRPI model if data to construct GRPI are not available. (Population Health Management 2014;17:54?59)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140179/1/pop.2012.0117.pd

    Experimental research on the effects of water application on greenhouse gas emissions from beef cattle feedlots

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    The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and were used as simulated pen surfaces. Three treatments (i.e., dry and loose, moist and loose, and moist and compacted pen surface conditions) were considered, simulating surface conditions in the field after a typical rainfall event or water application with a sprinkler system. Soil/manure and water were mixed within glass containers and analyzed for GHG emission using a photo-acoustic infrared multi-gas analyzer; emission rates were calculated from measured concentrations. GHG emissions from the dry soil/manure samples were low, with mean values of 0.02, 0.00, and 45 mg m−2 h−1 for N2O, CH4, and CO2, respectively, compared to moist soil/manure samples. Water application on the dry manure samples resulted in large peaks of GHG fluxes, with peak values of 99.2, 28.6, and 15,443 mg m−2 h−1 for N2O, CH4, and CO2, respectively.The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and were used as simulated pen surfaces. Three treatments (i.e., dry and loose, moist and loose, and moist and compacted pen surface conditions) were considered, simulating surface conditions in the field after a typical rainfall event or water application with a sprinkler system. Soil/manure and water were mixed within glass containers and analyzed for GHG emission using a photo-acoustic infrared multi-gas analyzer; emission rates were calculated from measured concentrations. GHG emissions from the dry soil/manure samples were low, with mean values of 0.02, 0.00, and 45 mg m−2 h−1 for N2O, CH4, and CO2, respectively, compared to moist soil/manure samples. Water application on the dry manure samples resulted in large peaks of GHG fluxes, with peak values of 99.2, 28.6, and 15,443 mg m−2 h−1 for N2O, CH4, and CO2, respectively

    Status review of Belding's Yellowthroat Geothlypis beldingi, and implications for its conservation

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    Summary Belding's Yellowthroat (Geothlypis beldingi) inhabits freshwater marshes the length of the state of Baja California Sur. A gap in occurrence from approximately 25u509N to 24u509N separates the subspecies goldmani to the north from beldingi to the south. According to BirdLife International's (2000International's ( , 2007 population estimates, the most important sites for the species are San Ignacio (537-648 birds) and La Purísima (203-450) in the north and San José del Cabo (219-480) and Punta San Pedro (70) in the south. Half of 12 presumed breeding sites in the north and five of 14 in the south were discovered within the last ten years. The species apparently no longer occurs at one historical site in the south. Since 2000, two records from Guerrero Negro and one from Bahía Tortugas approximately 140 km and . 200 km respectively northwest of the known breeding range demonstrate the species' dispersal ability. Belding's Yellowthroat is of utmost conservation concern, but the most recent conservation summaries exaggerated the species' plight, in particular by under-appreciating the bird's capacity for long-range dispersal and the ability of marsh habitat to regenerate quickly. Formal studies of the species should be undertaken and marsh creation should be incorporated in the state's development plans

    Work‐Related Outcomes After a Myocardial Infarction

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90385/1/phco.24.16.1515.50946.pd

    Phase Heritage: Deciphering Evidence of Pre-Existing Phases via Inherited Crystallographic Orientations

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    The concept of 'phase heritage' (e.g., Timms et al., 2017a) involves microstructural recognition of the former presence of a phase that has since transformed to another via evidence encoded in crystallographic orientations. Phase heritage relies on the phenomenon that newly grown (daughter) phases nucleate with particular crystallographic orientation relationships with the preceding (parent) phase. This phenomenon is common for displacive (i.e., shear or martensitic) transformations, well documented in the metals and ceramics literature, but is relatively uncommon in geosciences. This presentation outlines the concepts behind this approach, showcases results from software for automated analysis of EBSD data, and illustrates examples of polymorphic and dissociation phase transformations in the ZrSiO4-ZrO2-SiO2 system, which has particularly useful applications for 'extreme thermobarometry' in impact environments (Timms et al., 2017a)
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