Relative prognostic value of rest thallium-201 imaging, radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring after acute myocardial infarction

Rest thallium-201 scintigraphy, radionuclide ventriculography and 24 hour Holter monitoring are acceptable methods to assess myocardial necrosis, performance and electrical instability. This study examined the relative value of the three tests, when obtained a mean of 7 days after acute myocardial infarction, in predicting 1 year mortality in 93 patients. Planar thallium-201 images were obtained in three projections and were scored on a scale of 0 to 4 in 15 segments (normal score = 60).Patients were classified as having high risk test results as follows: thallium score ≤45 (33 patients), left ventricular ejection fraction ≤40% (51 patients) and complex ventricular arrhythmias on Holter monitoring (36 patients). During the follow-up of 6.4 ± 3.4 months (mean ± SD), 15 patients died of cardiac causes. All three tests were important predictors of survival by univariate Cox survival analysis; the thallium score, however, was the only important predictor by multivariate analysis. The predictive power of the thallium score was comparable with that of combined ejection fraction and Holter monitoring (chi-square = 21 versus chi-square = 22).Thus, rest thallium-201 imaging performed before hospital discharge provides important prognostic information in survivors of acute myocardial infarction which is comparable with that provided by left ventricular ejection fraction and Holter monitoring. Patients with a lower thallium score (large perfusion defects) are at high risk of cardiac death during the first year after infarction

A Lie Symmetry Classification of a Nonlinear Fin Equation in Cylindrical Coordinates

The nonlinear fin equation in cylindrical coordinates is considered. Assuming a radial variable heat transfer coefficient and temperature dependent thermal conductivity, a complete classification of these two functions is obtained via Lie symmetry analysis. Using these Lie symmetries, we carry out reduction of the fin equation and whenever possible exact solutions are obtained

Weighing the Milky Way

We describe an experiment to measure the mass of the Milky Way galaxy. The experiment is based on calculated light travel times along orthogonal directions in the Schwarzschild metric of the Galactic center. We show that the difference is proportional to the Galactic mass. We apply the result to light travel times in a 10cm Michelson type interferometer located on Earth. The mass of the Galactic center is shown to contribute 10^-6 to the flat space component of the metric. An experiment is proposed to measure the effect.Comment: 10 pages, 1 figur

Effect of Different Proportions of Magnesium reinforced Carbon Steel for Excavator Bucket Teeth

Effects of carbon steel with different proportions of magnesium were studied through mechanical properties for escavator bucket teeth applications. In this study, micron-sized magnesium particles were used as reinforcement to fabricate the carbon steel - Mg composites at two casting temperatures (650 and 830 °C) and stirring periods (3 and 6 min). In this regard, escavator bucket teeth are replaced by Magnesium based carbon steel material and it also describes the modeling and analysis of escavator bucket teeth. Tensile strength, bending strength and hardness of Caron steel with magnesium was improved in all proportions when compared to virgin carbon steel and existing chromium steel. These results indicated that, failure can be minimize by improving bucket tooth with fabrication of carbon steel and Magnesium alloy for more efficient digging and ground leveling. The project concludes that, usage of carbon steel-magnesium composites in the place of Excavator teeth; it can achieve reliability with less weight and high strength

Symmetries, Conservation Laws, and Wave Equation on the Milne Metric

Noether symmetries provide conservation laws that are admitted by Lagrangians representing physical systems. For partial differential equation possessing Lagrangians these symmetries are obtained by the invariance of the corresponding action integral. In this paper we provide a systematic procedure for determining Noether symmetries and conserved vectors for a Lagrangian constructed from a Lorentzian metric of interest in mathematical physics. For completeness, we give Lie point symmetries and conservation laws admitted by the wave equation on this Lorentzian metric

Performance and emission characteristics of a CI engine with post-treated plastic pyrolysis oil and diesel blend

Conversion of waste plastics into energy products is an effective waste management technique as they constitute a considerable portion of solid waste at present. In this study, distilled diesel fraction of Plastic Pyrolysis Oil (PPO) named Distilled Plastic Diesel (DPD) was hydrotreated named hydrotreated plastic diesel (HPD) and blended with commercial diesel fuel by 15:85 ratio (wt%), defined as HPD15, to experimentally investigate the performance and emission characteristics of a compression ignition (CI) engine. The experiment was done in 4-cylinder, 4-stroke diesel engine with an eddy current dynamometer testbed at full load (100 % engine load) and an engine speed of 1200–2400 rpm with 300 rpm intervals. The results are compared with neat diesel fuel data at the same operating conditions. This study found that HPD15 performed better or comparable with diesel fuel. Overall, the brake power (BP) and brake thermal efficiency (BTE) of HPD15 were higher than diesel fuel by a maximum of about 4.77 % and 3.77 %, respectively. Brake specific fuel consumption (BSFC) of HPD15 was lower at all operating speeds (by a maximum of about 4.66 %) and brake specific energy consumption (BSEC) was lower in most of the operating speeds (by a maximum of about 3.77 %). This study also revealed that CO2 at some operating speeds and NOx emission at all operating speeds for HPD15 are lower than diesel fuel. However, CO and unburnt hydrocarbon (UHC) emission are slightly higher for HPD15 than diesel at all speeds. Overall, HPD15 can be recommended as a suitable alternative for diesel fuel without any engine modification

Adomian Decomposition Method for a Nonlinear Heat Equation with Temperature Dependent Thermal Properties

The solutions of nonlinear heat equation with temperature dependent diffusivity are investigated using the modified Adomian decomposition method. Analysis of the method and examples are given to show that the Adomian series solution gives an excellent approximation to the exact solution. This accuracy can be increased by increasing the number of terms in the series expansion. The Adomian solutions are presented in some situations of interest