Beitrag zur Zeitstandfestigkeit von Chrom-Molybdän-Vanadin-Stählen für den Turbinenbau

Ergebnisse aus Zeitstandversuchen bis rd. 50000 h bei 500, 530 und 550°C an Proben aus dem Rand- und Kernbereich von 12 Turbinenwellen mit einem gröβten Vergütungsdurchmesser von 1190 mm aus Chrom-Molybdän-Vanadin-Stählen mit 0,21 bis 0,34% C, 1,06 bis 1,43% Cr, 0,56 bis 1,28% Mo, 0,09 bis 0,74% Ni und 0,17 bis 0,35% V sowie an Stabstahl Rd. 28 mm mit rd. 0,30% C, 1,15% Cr, 0,35% V und Molybdängehalten zwischen 0,11 und 1,15%.     

Lack of effect on ovariectomy on the metabolism of vitamin D and intestinal calcium-binding protein in female rats

A 20-year-old woman lost all useful vision over a 2 1/2-month period as a result of a necrotizing and occlusive vasculitis of the retina. Treatment with prednisone, immunosuppressants, and aspirin was unsuccessful. No systemic manifestations of the disease were found and no cause was discovered. Kodachromes and fluorescein angiograms showed the progression in one eye from normal to near total retinal necrosis. The process began with a mild venous dilation and peripheral arteritis that progressed into an obliterative vasculitis with abrupt vessel dilation, hemorrhages, and retinal swelling. This was followed by necrosis and sloughing of the retina into the vitreous. Vitreous contraction and necrotic retina produced unrepairable retinal detachments.     

Steep central islands after myopic photorefractive keratectomy

The nitric oxide synthase inhibitor 7-nitroindazole (7-NI) dose-dependently (3.0-30.0 mg/kg) displayed anxiolytic activity, as measured by an increase in open arm exploration time in the elevated plus-maze (EPM), following intraperitoneal (i.p.) administration in rats. Acute administration of 7-NI at 30.0 mg/kg significantly (P < 0.05) increased open arm exploration time by 176% compared to vehicle control, similar to the benzodiazepine diazepam at 1.0 and 3.0 mg/kg (+ 191 and + 200%, respectively). However, 39 h following subchronic 5-day administration of diazepam twice daily (bid) at 3.0 mg/kg, diazepam was devoid of anxiolytic activity at 1.0 mg/kg, as measured by no difference in open arm exploration time compared to vehicle control, while the 3.0 mg/kg dose still produced a significant (P < 0.05) 175% increase in open arm exploration time. In contrast, following subchronic administration of 7-NI (30.0 mg/kg, bid), a significant (P < 0.01) enhancement in open arm exploration time was observed at 30.0 mg/kg (+ 665% compared to control). Therefore, inhibition of nitric oxide synthase by 7-NI resulted in anxiolysis similar to diazepam following acute administration in the EPM. However, following subchronic administration, unlike diazepam which showed an attenuation of anxiolytic activity, 7-NI displayed enhanced anxiolytic efficacy and was devoid of tolerance.     

Lower time bounds for integer programming with two variables

In this paper an elementary version of the integer programming problem is considered, namely that of deciding whether a given triangle in the plane contains a point with integer coordinates. We prove two lower bounds for the number of operations necessary to solve this problem: (i) Ω(p) steps are necessary if operations from {+, -,%,, ?} are admissible, (ii) Ω(log p) steps are necessary if operations from {+, -, ?·?, ?} are admissible. Here, p denotes the binary length of the input and ?·? denotes the floor function. New techniques are necessary for relating the bounds to the length of the input—known methods only yield uniform bounds assuming all real inputs to be allowed—and for handling the floor function which prevents us from applying the well-known algebraic arguments.The best known algorithm is due to H.W. Lenstra, Jr. (preprint) and needs O(p) steps over {+, -, 1, %, ?·?, ?} (P. van Emde Boas, 1984).     

Über die Grundlagen der Warmfestigkeit,dargestellt an legierten Stählen

Darstellung der bei reinen Metallen sowie homogen und heterogen aufgebauten Legierungen das Kriechverhalten bestimmenden Vorgänge. Übertragung der Modellvorstellungen auf die Gegebenheiten bei warmfesten Stählen. Zusammenhang zwischen dem Werkstoffaufbau (Gefüge, Ausscheidungszustand) und den Langzeit-Festigkeitseigenschaften legierter Stähle mit Chrom und Molybdän sowie Chrom, Molybdän und Vanadin.     

8-channel optical demultiplexer realized as SiO2/Siflat-field spectrograph

The operation of a flat-field spectrograph in silica on silicon (SiO₂/Si) for 2-nm channel spacing is demonstrated. Crosstalk attenuations of >20 dB and significantly reduced fiber-to-fiber insertion losses of 5 dB could be obtained     

Locating illicit connections in storm water sewers using fiber-optic distributed temperature sensing

A newly developed technique using distributed temperature sensing (DTS) has been developed to find illicit household sewage connections to storm water systems in the Netherlands. DTS allows for the accurate measurement of temperature along a fiber-optic cable, with high spatial (2 m) and temporal (30 s) resolution. We inserted a fiber-optic cable of 1300 m in two storm water drains. At certain locations, significant temperature differences with an intermittent character were measured, indicating inflow of water that was not storm water. In all cases, we found that foul water from households or companies entered the storm water system through an illicit sewage connection. The method of using temperature differences for illicit connection detection in storm water networks is discussed. The technique of using fiber-optic cables for distributed temperature sensing is explained in detail. The DTS method is a reliable, inexpensive and practically feasible method to detect illicit connections to storm water systems, which does not require access to private property.     

Liver microcirculation analysis by red blood cell motion modeling in intravital microscopy images

Intravital microscopy has been used to visualize the microcirculation by imaging fluorescent labeled red blood cells (RBCs). Traditionally, microcirculation has been modeled by computing the mean velocity of a few, randomly selected, manually tracked RBCs. However, this protocol is tedious, time consuming, and subjective with technician related bias. We present a new method for analyzing the microcirculation by modeling the RBC motion through automatic tracking. The tracking of RBCs is challenging as in each image, as many as 200 cells move through a complex network of vessels at a wide range of speeds while deforming in shape. To reliably detect RBCs traveling at a wide range of speeds, a window of temporal template matching is applied. Then, cells appearing in successive frames are corresponded based on the motion behavior constraints in terms of the direction, magnitude, and path. The performance evaluation against a ground truth indicates the detection accuracy up to 84% TP at 6% FP and a correspondence accuracy of 89%. We include an in-depth discussion on comparison of the microcirculation based on motion modeling from the proposed automated method against a mean velocity from manual analysis protocol in terms of precision, objectivity, and sensitivity.