64 research outputs found
Attenuation and Velocity of Ultrasound Near the Critical Point of Gallium-Bismuth
No full textTitle: Attenuation and Velocity of Ultrasound Near the Critical Point of Gallium-Bismuth, Author: Manfred P. Puls, Location: ThodeAttenuation measurements were performed on a liquid Ga-Bi mixture above its miscibility gap and at the frequencies 16.6, 25.5, 37.6 and 49.7 MHz. The attenuation measurements were made over a composition range from 0.20 to 0.75 weight-fraction Bismuth and in the temperature range 0.3 to 9.9°C above the critical temperature of the mixture. For a mixture at the critical composition, attenuation measurements were also made 27.2°C above the critical temperature. The velocity of sound was measured at 25.5MHz and at each of the above temperature and composition points. The critical temperature and composition of the Ga-Bi system have been determined to improve accuracy as 263.1°C and 0.60 weight-fraction Bismuth, respectively. The attenuation results have been tested against current theories and these theories have been subject to critical analysis.ThesisDoctor of Philosophy (PhD
Heart-type fatty acid-binding protein permits early risk stratification of pulmonary embolism
No full textAims We investigated the value of a novel early biomarker, heart-type fatty acid-binding protein (H-FABP), in risk stratification of patients with acute pulmonary embolism (PE). Methods and results We prospectively included 107 consecutive patients with confirmed PE. The endpoints were (i) PE-related death or major complications and (ii) overall 30-day mortality. Overall, 29 patients (27%) had abnormal (> 6 ng/mL) H-FABP levels at presentation. Of those, 12 (41%) had a complicated course, whereas all patients with normal baseline H-FABP had a favourable 30-day outcome (OR, 71.45; P < 0.0001). At multivariable analysis, H-FABP (P < 0.0001), but not cardiac troponin T (P = 0.13) or N-terminal pro-brain natriuretic peptide (P = 0.36), predicted an adverse outcome. Evaluation of a strategy combining biomarker testing with echocardiography revealed that patients with a negative H-FABP test had an excellent prognosis regardless of echocardiographic findings. In contrast, patients with a positive H-FABP test had a complication rate of 23.1% even in the presence of a normal echocardiogram, and this rose to 57.1% if echocardiography also demonstrated right ventricular dysfunction (OR vs. a negative H-FABP test, 5.6 and 81.4, respectively). Conclusion H-FABP is a promising early indicator of right ventricular injury and dysfunction in acute PE. It may help optimize risk stratification algorithms and treatment strategies
The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking
No full textBy drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the focus lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals. This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing that our understanding of DHC is supported by progress across a broad range of fields. These include hysteresis associated with first-order phase transformations; phase relationships in coherent crystalline metallic solids; diffusion of substitutional and interstitial atoms in crystalline solids; and continuum fracture and solid mechanics. Furthermore, an account of current methodologies is given, illustrating how such understanding of hydrogen, hydrides and DHC in zirconium alloys underpins these methodologies for assessments of real life cases in the Canadian nuclear industry. The all-encompassing approach makes The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Component: Delayed Hydride Cracking an ideal reference source for students, researchers and industry professionals alike
- …
