Bemerkungen zu der Arbeit von Lauersen und Orth: Die Verteilung der Ascorbins?ure in der Kartoffelknolle

Ohne ZusammenfassungDiese Z.83, 193 (1942).     

Investigation of Decarburization in Spring Steel Production Process – Part I: Experiments

Decarburization and oxidation have considerable influence on the product properties of spring steels. The investigations in part I of this paper concentrate on the experimental determination of the influence of different thermal cycles on the decarburization process. With the thermo‐mechanical simulator Gleeble 1500, the influence of different process parameters, such as the time between furnace reheating and hot rolling, the hot rolling temperature, finish rolling temperature, laying temperature, and the α→γ phase transformation temperature range, is systematically investigated. In part II of this paper [15], numerical simulation techniques are applied to simulate the decarburization behavior under the experimental conditions, which are described in the present part I.     

Reliability and validity of self-reported assessment of exposure and outcome variables for manual lifting tasks: a preliminary investigation

The reliability and validity of self-reported assessment of exposure and outcome variables were examined for manual lifting activities among ten physiotherapists. In this study, the participants evaluated the effects of five lifting variables on perceived effort, twice separated by a one-week period. One hundred and sixty-two lifting conditions were evaluated by each subject. The exposure and outcome lifting variables were described in linguistic terms. Intra-class correlation coefficient (ICC(1,1)) analysis revealed a mean value of 0.62 for all lifting activities. The self-reported assessment was cross-validated with the NIOSH lifting index by mapping the linguistic variables into numerical ranges. Moderate correlations (r = 0.54 and 0.53, p<0.01) were obtained between perceived physical exertion/perceived risk and lifting index. The findings of this study provide preliminary indications that human-based methodologies may be further explored on experienced workers.     

Mechanical Properties and Bake Hardening Behaviour of two Cold Rolled Multiphase Sheet Steels subjected to CGL Heat Treatment Simulation

In recent years, multiphase steels have become a material of choice for use in the car manufacturing industry owing to their excellent mechanical properties. It is anticipated that in the years to come these steels will show the highest increase in usage. A particular aspect of their potential is that multiphase steels often show good bake hardening (BH) properties. The main factors that govern the microstructures and the properties of these steels are the chemical composition and the production process parameters. In this work two commercial cold rolled sheet steels with different carbon content were investigated. In order to produce dual phase (DP) steels with a ferrite‐martensite microstructure, the as‐received material was subjected to heat treatment simulating continuous galvanising line (CGL) cycles with an overageing zone before the zinc pot. After a first CGL cycle predominantly ferritic microstructures with small amounts of martensite, pearlite and retained austenite were obtained, which resulted in deviations from typical DP properties, e.g. in the occurrence of discontinuous yielding. A higher line speed led to improved mechanical properties. BH prestrain was varied between 0 and 10%. While only very little bake hardening was observed without prestrain, with increasing prestrain the amount of BH was evolving quickly towards larger values of more than 60 MPa. Generally, the BH values were somewhat larger for higher carbon content. Finally, an optimised CGL cycle was simulated at laboratory scale with changes in the process parameters. Thus, characteristic DP microstructures resulting in desired mechanical properties were obtained. For these optimised conditions, BH₂ values in excess of 60 MPa were achieved for both steels investigated.     

Time course of pulmonary artery pressure during sleep in sleep apnoea syndrome: role of recurrent apnoeas

Recent results in animals have suggested that repetition of hypoxaemic stimuli may result in a progressive increase in pulmonary arterial pressure (Ppa). The purpose of the present study was to investigate the effects of recurrent obstructive apnoeas on Ppa. We have, therefore, examined the nocturnal trend of Ppa in seven obstructive sleep apnoea syndrome (OSAS) patients and in five snorers. Mean Ppa was measured before, at the start, at the end and after the selected apnoeas. The analysis was performed for each 1 h period for at least 7 h throughout the night on at least 10 randomly selected apnoeas per hour. In snorers, 100 randomly chosen values were measured during every hour of the night. In the morning after the nocturnal study, the Ppa responses to acute hypoxia and hypercapnia were measured. No Ppa changes throughout the 7 h were found during sleep in snorers [Ppa slope:-0.002+/-0.10 mmHg x h(-1)]. In OSAS patients a small but significant increase in Ppa throughout the night was noted, affecting the values before [Ppa slope: 0.7+/-0.16 mmHg x h(-1)], at the start of apnoea [Ppa slope: 0.530.1 mmHg x h(-1)] as well as at the end [Ppa slope: 0.44+/-0.08 mmHg x h(-1)] and in the postapnoeic period [Ppa slope: 0.55+/-0.1 mmHg x h(-1)]. When we limited the analysis to nonrapid eye movement (NREM) sleep, a trend in progressive Ppa was also present, irrespective of changes in apnoea duration and apnoea desaturation. The Ppa rise during the night was not affected by diurnal Ppa pulmonary vascular response to hypoxia and hypercapnia or indices of sleep apnoea severity. We conclude that in obstructive sleep apnoea, pulmonary artery pressure progressively increases during the night, reflecting the cumulative effects of apnoeas and nocturnal hypoxaemia.     

Prinzip-Analyse von zwei Röntgen-Verformungsmeßverfahren

Erläuterung der Methoden zur Ermittlung mechanischer Spannungen unter besonderer Berücksichtigung der räumlichen Verhältnisse bei der Röntgenmessung. Darstellung der Verformungsgeometrie und der daraus abgeleiteten Meßverfahren. Vergleichende Gegenüberstellung des Röntgen-φ-Integralverfahrens mit dem Röntgen-ψ-Integralverfahren.     

An assessment system for rating scientific journals in the field of ergonomics and human factors

A method for selecting and rating scientific and professional journals representing the discipline of ergonomics and human factors is proposed. The method is based upon the journal list, impact factors and citations provided by the Institute of Scientific Information (ISI), and the journal list published in the Ergonomics Abstracts. Three groups of journals were distinguished. The 'ergonomics journals' focus exclusively on ergonomics and human factors. The 'related journals' focus on other disciplines than ergonomics and human factors, but regularly publish ergonomics/human factors papers. The 'basic journals' focus on other technical, medical or social sciences than ergonomics, but are important for the development of ergonomics/human factors. Journal quality was rated using a maximum of four categories: top quality (A-level), high quality (B-level), good quality (C-level)) and professional (P-level). The above methods were applied to develop the Ergonomics Journal List 2004. A total of 25 'ergonomics journals', 58 'related journals' and 142 'basic journals' were classified.     

Effect of 5-hydroxytryptamine on the peripheral chemoreceptors in the rat

5-Hydroxytryptamine (5-HT), in the doses of 2-5 mug/kg injected into the carotid body area, produced a significant increase in the respiratory rate and carotid sinus nerve activity. Selective ablation of the ipsilateral carotid sinus nerve abolished the respiratory stimulation produced by the drug. On the other hand, the same doses of 5-HT injected into the ascending aorta did not produce stimulation of respiration when the carotid sinus nerves were sectioned. The activity of the aortic nerves did not increase after injecting the drug into the ascending aorta or at the root of the right subclavian artery. These results indicate that 5-HT stimulates the chemoreceptors in the carotid body of the rat. The lack of responses to the injections of the drug in the aortic or subclavian region was due to the absence of chemoreceptors in these regions of the rat.