Wärmeübertragung in dissoziierenden Gasen bei schneller und gehemmter Gleichgewichtseinstellung

Stoff- und Transporteigenschaften von dissoziierenden Oasen: Spezifische Wärme, Wärmeleitzahl, Enthalpie, Viskosität, Diffusionskoeffizient. Aufstellung von Grenzschicht-Differentialgleichungen dissoziierender Gase für die Wärmeübertragung bei schneller Gleichgewichtseinstellung. Versuche zur Wärmeübertragung bei schneller Gleichgewichtseinstellung am N₂O₄–NO₂-Gemisch und deren Ergebnisse. Wärmeübertragung bei gehemmter Gleichgewichtseinstellung mit fallendem Druck. Ergebnisse für natürliche und erzwungene Konvektion am horizontalen Zylinder.     

Die Erhöhung der Grundfrequenz und der Beullast von Kreisplatten durch geeignete plastische Verformung

Zusammenfassung Eine M?glichkeit, ohne Mehraufwand an Material oder Verwendung teurerer Werkstoffe das dynamische Verhalten oder die Tragf?higkeit von Bauteilen zu verbessern, wird am Beispiel der Grundfrequenz- und Beullaststeigerung von Kreisplatten durch das Einpr?gen von geeigneten Eigenspannungszust?nden dargelegt. Die Ergebnisse einer Optimierung solcher Eigenspannungsfelder werden dargestellt, und die M?glichkeit der Erzeugung geeigneter Eigenspannungszust?nde wird an Hand eines Experiments nachgewiesen.     

Neutralizing Coal Mine Effluent with Limestone to Decrease Metals and Sulphate Concentrations

Abstract.   This paper describes pilot scale tests of a novel process for the neutralisation of acidic mine water. Leachate from a waste coal dump was neutralised with limestone, and iron, aluminium, and sulphate were removed. Specific aspects studied were: the process configuration; the rates of iron oxidation, limestone neutralisation, and gypsum crystallisation; the chemical composition of the effluents before and after treatment; the efficiency of limestone utilisation; and the sludge solids content. The acidity was decreased from 12,000 to 300 mg/L (as CaCO₃), sulphate from 15,000 to 2,600 mg/L, iron from 5,000 to 10 mg/L, aluminium from 100 to 5 mg/L, while the pH increased from 2.2 to 7.0. Reaction times of 2.0 and 4.5 h were required under continuous and batch operations respectively for the removal of 4 g/L Fe (II). The iron oxidation rate was found to be a function of the Fe (II), hydroxide, oxygen, and suspended solids (SS) concentrations. The optimum SS concentration for iron oxidation in a fluidised-bed reactor was 190 g/L. Up-flow velocity had no influence on the rate of iron oxidation in the range 5 to 45 m/h. Sludge with a high solids content of 55% (m/v) was produced. This is high compared to the typical 20% achieved with the high density sludge process using lime. It was determined that neutralisation costs could be reduced significantly with an integrated iron oxidation and limestone neutralisation process because limestone is less expensive than lime, and a high-solids-content sludge is produced. Full scale implementation followed this study.     

Distractibility in dieters and nondieters: An alternative view of "externality."

Performed 2 experiments in an investigation of the effects of distraction and emotional arousal on the proofreading performance of 60 dieting and nondieting female undergraduates. In Exp I, it was found that distraction initially impaired the performance of dieters and facilitated the performance of nondieters, a pattern previously shown by J. Rodin (see record 1973-27101-001) to apply to obese and normal weight Ss, respectively, and interpreted as evidence of greater externality in the obese. Subsequent retesting of the same Ss in succeeding months, however, revealed a complete reversal of the original results. In Exp II, the reaction to distraction found in the first phase of Exp I was obtained when Ss were in a situation of minimal threat. In a situation of high threat, the relative distractibility of dieters was reversed, as in the latter phases of Exp I. An explanation is offered for these data in terms of the greater emotionality of dieters, the susceptibility of cognitive performance to arousal (distraction, anxiety) manipulations, and the potentially competing effects of distraction and anxiety. Implications for the prevailing "trait" view of externality (stimulus binding) are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Damage threshold prediction of hafnia-silica multilayer coatings by nondestructive evaluation of fluence-limiting defects

A variety of microscopic techniques were employed to characterize fluence-limiting defects in hafnia-silica multilayer coatings manufactured for the National Ignition Facility, a fusion laser with a wavelength of 1.053 mum and a pulse width of 3 ns. Photothermal microscopy, with the surface thermal lens effect, was used to map the absorption and thermal characteristics of 3 mm x 3 mm areas of the coatings. High-resolution subaperture scans, with a 1-mum step size and a 3-mum pump-beam diameter, were conducted on the defects to characterize their photothermal properties. Optical and atomic force microscopy were used to identify defects and characterize their topography. The defects were then irradiated by a damage testing laser (1.06 mum and 3 ns) in single-shot mode until damage occurred. The results were analyzed to determine the role of nodular and nonnodular defects in limiting the damage thresholds of the multilayer coatings. It was found that, although different types of defect were present in these coatings, the fluence-limiting ones had the highest photothermal signals (up to 126x over the host coating). The implication of this study is that coating process improvements for hafnia-silica multilayer coatings should have a broader focus than just elimination of source ejection, since high photothermal signals frequently occur at nodule-free regions. The study also demonstrates that, for optics subject to absorption-induced thermal damage, photothermal microscopy is an appropriate tool for nondestructive identification of fluence-limiting defects.     

(31)P-MR Spectroscopy for the evaluation of energy metabolism in intact residual myocardium after acute myocardial infarction in humans

Objective experimental studies have demonstrated that acute myocardial infarction (MI) alters energy metabolism even in non-infarcted adjacent tissue. In patients with subacute MI, the influence of the regional ischemie insult on energy metabolism of intact septal myocardium was analyzed using³¹P-Magnetic resonance spectroscopy (MRS). Patients and Methods in eight patients with wall motion abnormalities in the anterior wall³¹P-spectra were obtained from non-infarcted adjacent scptal myocardium, as well as infarcted anterior myocardium (voxel size 25 ccm each) 29 ±8 days after MI using a 3D-CSI technique. Additionally, cardiac function was analyzed using breath-hold cine MRI. MR1 was repeated 6 months after revascularization to assess viability of infarcted segments. Eight age-matched healthy volunteers served as control group. Results according to follow-up MRI 4/8 patients showed regional wall motion recovery. Here, PCr/ATP-ratios were not significantly reduced in intact septal myocardium as well as infarcted anterior myocardium compared to healthy volunteers (1.28 ±0.10 and 1.14 ±0.09 vs. 1.45 ±0.29). No recovery of regional function was detected in 4/8 patients with —therefore—non-viable anterior myocardium. PCr/ATP-ratios were significantly reduced in intact and infarcted myocardium compared with healthy volunteers as well as to patients with wall motion recovery (0.77 ±0.17 and 0.49 ±0.23;P < 0.05). Discussion these preliminary results indicate that energy metabolism is reduced in patients with persisting wall motion abnormalities after myocardial infarction and revascularization in ischemically injured as well as in adjacent non-injured myocardium.     

Common and specific process factors in cardiac rehabilitation: Independent and interactive effects of the working alliance and self-efficacy.

Objective: Therapeutic processes in cardiac rehabilitation programs are virtually unexamined. Models were tested by which changes in the working alliance between patient and staff (agreement on goals/tasks; emotional bond) may affect outcomes in conjunction with changes in patient self-efficacy to change their diets and increase exercise. Design: Cardiac patients (n = 79) participated in a 12-week program, and completed assessments at early, mid, and late treatment. Main Outcome Measures: Changes in cardiac depression, physical health, perceived exertion during exercise, rate/pressure product at submaximal exercise tolerance, weight loss, return to work, total fat intake. Results: Early-treatment changes in agreement on goals/tasks were related to changes in psychosocial factors and perceived exertion during exercise independent of effects of changes in self-efficacy. Early-treatment changes in goals/tasks and self-efficacy interacted to predict changes in cardiorespiratory fitness, weight loss, and return to work such that patients high on both goals/tasks and self-efficacy showed the most gains. Conclusion: Sound therapeutic relationships between patients and staff may play an important role in facilitating the achievement of a wide-range of salutary outcomes during cardiac rehabilitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extended Tunability in a Two-Chip VECSEL

We demonstrate a widely tunable vertical-external-cavity surface-emitting laser (VECSEL) with a W-shaped cavity, in which two VECSEL chips serve as fold mirrors and a birefringent filter is inserted at Brewster's angle. These two chips provide much higher modal gain and broader bandwidth of the gain than a single chip does, enhancing the VECSEL tuning range and reducing the variation of tunable output power with the tuned wavelength. This two-chip VECSEL configuration makes it possible to shape the modal gain spectra of the laser or to manipulate the tuning curve of the laser by two different chips with certain gain peak detuning (offset). Multiwatts high-brightness linearly polarized output with a tuning range of 33 nm is demonstrated in such a two-chip VECSEL     

Second Generation Nanostructured Metal Oxide Matrices to Increase the Thermal Stability of CO and NO2 Sensing Layers Based on Iron(II) Phthalocyanine

An iron(II) phthalocyanine (FePc) complex solubilized by decylamine (DA) and benzylamine (BA) is incorporated into a nanoparticulate metal oxide matrix to develop optical sensor films sensitive to NO₂ and CO. Eleven amine solvents have been tested as N‐donor ligands that permit ligand exchange with the gas molecules. We have systematically investigated the suitability of different N‐donor ligands, studied the thermal stability of the NO₂‐ and CO‐sensing films at 4, 25, 60, and 80 °C by photometry, and corroborated our findings by using NMR experiments. A satisfactory thermal stability of the films has not been obtained for chemically unmodified nanoparticulate metal oxide matrices. We have therefore developed a second generation of nanostructured metal oxide supports that show increased thermal stability and adequate sensitivity to NO₂ and CO. These novel nanostructured matrices have been chemically modified using amines, alumina oligomers, and/or anti‐gas‐fading agents. These components have been integrated into the metal oxide matrices to avoid degradation of the optical films and to preserve their sensitivity.