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.     

Seasonal optimal mix of wind and solar power in a future,highly renewable Europe

The renewable power generation aggregated across Europe exhibits strong seasonal behaviors. Wind power generation is much stronger in winter than in summer. The opposite is true for solar power generation. In a future Europe with a very high share of renewable power generation those two opposite behaviors are able to counterbalance each other to a certain extent to follow the seasonal load curve. The best point of counterbalancing represents the seasonal optimal mix between wind and solar power generation. It leads to a pronounced minimum in required stored energy. For a 100% renewable Europe the seasonal optimal mix becomes 55% wind and 45% solar power generation. For less than 100% renewable scenarios the fraction of wind power generation increases and that of solar power generation decreases.     

3D optical coherence tomography as new tool for microscopic investigations of nucleate boiling on heated surfaces

Boiling phenomena are an important aspect in security and efficiency for technical applications with high heat flux like nuclear reactors. This study presents optical coherence tomography (OCT) as a novel modality for three-dimensional and two-dimensional time resolved imaging of nucleate boiling on heated surfaces on a microscopic scale with high spatial (<10 μm) and temporal (>25 frames per second) resolution. Within this study, a borosilicate glass plate coated with an optically transparent and electrically conductive indium tin oxide (ITO) layer with a thickness of approximately 100 nm was used as heating surface. The combination of these two properties allows optical inspection of the nucleate boiling from the backside by OCT focused on the formation, growth and detachment of single bubbles. We demonstrated for the first time that OCT is an excellent tool to acquire two-dimensional and three-dimensional images of the base of vapor bubbles from the backside of the heated surface. The acquired images allow for instance the temporally resolved measurement of the bubble diameter, diameter of the bubble base and the contact angle. Exploiting the phase information of the acquired OCT signal stacks allows imaging the movement of the bubble surrounding fluid. We think that OCT will provide many new insights into the boiling phenomena at the bubble base. The recent enhancement of the acquisition rates of OCT systems will facilitate four-dimensional imaging of single bubble evaporation procedures in the nearer future.     

Werkstoffcharakterisierung mittels dreidimensionaler Atomsonde

The three-dimensional atom probe is a nanoanalytical instrument capable of reconstructing the three-dimensional element distribution of chemical inhomogenities, e.g. precipitates, in metallic materials. The atom probe became one of the most important methods for characterizing materials in nanometer scale. The basic principle of this method is the field evaporation and ionization of material atoms and the localization of generated ions on a position-sensitive multidetector. Chemical species are identified by time-of-flight mass spectrometry. Examples of applications as well as the performance of a three-dimensional atom probe are described and discussed.     

Water retention of wood particles – characterization of polarity and particle size

The basic principle of methods measuring water retention of fibre pulp was adapted for a new method to prove differences in polarity and particle size of wooden particles used for particle board production. With this new method, particles come into contact with the liquid for a short time. Besides the laboratory method, appropriate data analyses of the weight-time curves, including the calculation of a novel polarity coefficient are introduced. The measurement signal was found to be most significantly influenced by the particle properties at the equilibrium of liquid charge and discharge, as well as within the asymptotic levelling phase around 30 s of testing. With increasing particle size, water retention values of both native and thermally modified particles decrease due to reduced specific particle surface. Thermally modified particles show significantly lower water retention values in the range of ?28 to ?46 % and higher variability which is thought to be related to reduced polarity. The method proved to be quick, easy to handle and reproducible.     

Evaluation of Histamine and Other Biogenic Amines and Bacterial Isolation in Canned Anchovies Recalled by the USFDA

ABSTRACT: Histamine and other biogenic amines were evaluated in canned anchovies recalled by the U.S. Food and Drug Administration. In addition, bacteria were isolated from the products and identified to species. The recalled products were divided into 2 groups of high and low histamine, depending on the histamine contents as determined by the AOAC method. The high histamine group had the histamine contents >200 ppm, and 24 of the 30 cans analyzed belonged to this group. The most prevalent biogenic amine in this group was histamine followed by cadaverine. On the other hand, the low histamine group of 6 cans contained approximately 50 ppm histamine. The most prevalent biogenic amine found in this group of samples was cadaverine at levels >200 ppm. Other biogenic amines, such as putrescine, serotonin, and spermidine, were also detected in all the products, although at varied levels. Aerobic and anaerobic bacterial counts, if present in all of the recalled products, were below the detection limit of 10² colony-forming units (CFU)/g. Bacteria were recovered only after enrichment of the test samples. They were mostly halophilic bacteria. Bacillus spp. were most frequently identified, followed by Staphylococcus spp. However, these isolates produced negligible amounts of histamine in culture broth, indicating that they are not the contributors to histamine accumulation in the canned anchovies.