Unification in datastructure multisets

In a recent paper A. Herold and J. Siekmann generalize pure AC unification to terms containing additional function symbols. Generalized AC unification thus attains practical relevance for a broad range of applications. Pure AC unification is used as a basic mechanism and it is this key role that has motivated our research. We have improved upon earlier approaches by basing (pure) AC unification on a firm theoretical basis and presenting algorithms which fully exploit the properties of the underlying mathematical structure. In particular, the high degree of parallelism for AC unification will become apparent. Our algorithms have been designed for parallel hardware but still yield significant improvements over earlier algorithms when used in the sequential mode.     

SOME OBSERVATIONS ON THE AGING OF ENAMELS1

The tendency toward more rapid production of enameled ware has reduced to minimum the time allowed in most plants for aging of enamels. Aging of the enamel slip allows the clay to become thoroughly slaked, adsorb the larger enamel particles, and thus prepare it for its cohesion to the metal base. Aging or soaking of the clay before use is an excellent substitute for part of the time consumed in aging the enamel slip. Observations of results obtained in commercial application of enamels has lead to the following conclusions: (1) Enamels should be aged before use in order to gain the full benefit of the adsorption properties of the clay and enamel colloids. (2) If the proper time of aging of enamels cannot be allowed, at least the clay should be brought to fine state of subdivision by aging or soaking in water. (3) If aging is not allowed in some form, the enamel usually is not as easily applied with the ordinary handling encountered in average production. (4) If aging of the clay is allowed there is quicker turn over of the stock enamel in the mill room.     

A New Method for the Study of Adhesion: Application of Inelastic Electron Tunneling Spectroscopy

Inelastic electron tunneling spectroscopy provides an incredibly sensitive and versatile method of detecting and identifying molecular species adsorbed on the surface of a metal oxide. IETS spectra have been measured on the components of the commercial adhesive, Hercules 3501. This epoxy system consists of two molecular components; diamino diphenyl sulfone (DPS) and tetraglycidycl 4,4' diamino diphenyl methane (DPM). IETS spectra of the individual components and of the epoxy mixture adsorbed on aluminum oxide have been obtained and the vibrational modes and frequencies assigned by comparison with computer calculations and existing infrared optical spectra.

IETS is a useful tool for the study of molecular adhesion to an oxide. It is one of the most important methods available for determining the interface physics and chemistry of adhesive bondlines. Its usefulness is greatly enhanced by the fact that in situ studies can be made.

Spectra have been obtained on the components and mixture of the high performance, two component epoxy Hercules 3501. The vibrational modes were identified by comparison with infrared and Raman data, and with computer calculations using force constant information. Evidence for an aging effect was found in the DPS component.

It is suggested that initial studies using IETS should be applied to adhesives of simple molecular structure before proceeding to more complex systems.     

Large scale graph-based SLAM using aerial images as prior information

The problem of learning a map with a mobile robot has been intensively studied in the past and is usually referred to as the simultaneous localization and mapping (SLAM) problem. However, most existing solutions to the SLAM problem learn the maps from scratch and have no means for incorporating prior information. In this paper, we present a novel SLAM approach that achieves global consistency by utilizing publicly accessible aerial photographs as prior information. It inserts correspondences found between stereo and three-dimensional range data and the aerial images as constraints into a graph-based formulation of the SLAM problem. We evaluate our algorithm based on large real-world datasets acquired even in mixed in- and outdoor environments by comparing the global accuracy with state-of-the-art SLAM approaches and GPS. The experimental results demonstrate that the maps acquired with our method show increased global consistency.     

Characterization of the supercontinuum radiation generated by self-focusing of few-cycle 800 nm pulses in argon

Self-focusing of few-cycle pulses in atmospheric-pressure argon results in a supercontinuum which differs remarkably from the case of longer pulses: under single-filament conditions it extends to 200 nm and 250 nm with 6 fs and 10 fs pulses, respectively; the radiation, including the shortest wavelengths, is collimated and shows no conical emission. The short-wavelength part is intrinsically at least as short as the incoming fundamental pulse. These features make the few-cycle supercontinuum attractive as a source of widely tunable 10 fs pump pulses for spectroscopic applications. We present extensive experimental results including the dependence of the spectrum on pulse energy, duration and chirp, filament length, gas pressure and a comparison with nitrogen and air. We discuss them and other features including the role of the third harmonic and identify the conditions required to get a single highly stable filament. We also present a model, based on self-guiding, which predicts useful scaling rules.     

Structural,Pro-Inflammatory and Calcium Handling Remodeling Underlies Spontaneous Onset of Paroxysmal Atrial Fibrillation in JDP2-Overexpressing Mice

Background: Cardiac-specific JDP2 overexpression provokes ventricular dysfunction and atrial dilatation in mice. We performed in vivo studies on JDP2-overexpressing mice to investigate the impact of JDP2 on the predisposition to spontaneous atrial fibrillation (AF). Methods: JDP2-overexpression was started by withdrawal of a doxycycline diet in 4-week-old mice. The spontaneous onset of AF was documented by ECG within 4 to 5 weeks of JDP2 overexpression. Gene expression was analyzed by real-time RT-PCR and Western blots. Results: In atrial tissue of JDP2 mice, besides the 3.6-fold increase of JDP2 mRNA, no changes could be detected within one week of JDP2 overexpression. Atrial dilatation and hypertrophy, combined with elongated cardiomyocytes and fibrosis, became evident after 5 weeks of JDP2 overexpression. Electrocardiogram (ECG) recordings revealed prolonged PQ-intervals and broadened P-waves and QRS-complexes, as well as AV-blocks and paroxysmal AF. Furthermore, reductions were found in the atrial mRNA and protein level of the calcium-handling proteins NCX, Cav1.2 and RyR2, as well as of connexin40 mRNA. mRNA of the hypertrophic marker gene ANP, pro-inflammatory MCP1, as well as markers of immune cell infiltration (CD68, CD20) were increased in JDP2 mice. Conclusion: JDP2 is an important regulator of atrial calcium and immune homeostasis and is involved in the development of atrial conduction defects and arrhythmogenic substrates preceding paroxysmal AF.     

Device‐Level Photonic Memories and Logic Applications Using Phase‐Change Materials

Inspired by the great success of fiber optics in ultrafast data transmission, photonic computing is being extensively studied as an alternative to replace or hybridize electronic computers, which are reaching speed and bandwidth limitations. Mimicking and implementing basic computing elements on photonic devices is a first and essential step toward all‐optical computers. Here, an optical pulse‐width modulation (PWM) switching of phase‐change materials on an integrated waveguide is developed, which allows practical implementation of photonic memories and logic devices. It is established that PWM with low peak power is very effective for recrystallization of phase‐change materials, in terms of both energy efficiency and process control. Using this understanding, multilevel photonic memories with complete random accessibility are then implemented. Finally, programmable optical logic devices are demonstrated conceptually and experimentally, with logic “OR” and “NAND” achieved on just a single integrated photonic phase‐change cell. This study provides a practical and elegant technique to optically program photonic phase‐change devices for computing applications.     

Seismic vulnerability of historical masonry buildings for different earthquake characteristics: Case study of the mosque of Takiyya al‐Sulaymaniyya

Different factors influence the collapse behaviour of masonry structures, and one of the major factors is the characteristics of the earthquake itself. This effect is going to be more complicated for historical constructions, which involve different structure members of different geometries. The present study focuses on the effect of earthquake characteristics on the collapse behaviour of historical masonry structures. The effect of earthquake direction and the frequency content of the earthquake are mainly considered. A brief background of the selected case study and modelling process are presented. The geometry of the whole structure is created using micro modelling strategy. The collapse analysis of the structure is performed under artificial model based on the earthquake characteristics. Unidirectional earthquake are applied to the structure from different angels in order to investigate the weakest situation. Finally, different earthquake models are generated with different frequency contents according the soil profiles and applied consequently on the structure to explore the worst situation. Seismische Gefährdung von historischen Mauerwerksbauten infolge Erdbebeneinwirkung — Fallstudie: Die Moschee von Takiyya al‐Sulaymaniyya. Verschiedene Faktoren beeinflussen das Versagen von Mauerwerksstrukturen. Ein wesentlicher ist die Erdbebeneinwirkung selbst. Deren Charakteristik und Auswirkung ist für historische Konstruktionen, welche aufgrund der verschiedenen verwendeten und zusammenwirkenden Tragelemente und der großen Bandbreite geometrischer Formen eine komplexe Versagensabhängigkeit aufweisen, noch schwieriger einzuschätzen. Die in diesem Beitrag beschriebene Fallstudie befasst sich mit dem Verhalten historischer Mauerwerkskonstruktionen beim Versagen infolge einer Erdbebenbelastung. Die Auswirkungen von Richtung und Frequenz eines Erdbebens sind die Hauptschwerpunkte der Studie. Ein kurz gefasster Hintergrund der gewählten Fallstudie und der Modellierungsprozess werden vorgestellt. Die Geometrie der gesamten Konstruktion wurde mittels Mikromodellierung erstellt. Die Versagensanalyse der Konstruktion ist mittels eines künstlich generierten Erdbebens durchgeführt worden. Das einachsige Erdbeben wurde mit variierenden Richtungswinkeln auf das Modell angesetzt, um die schwächste Achse zu ermitteln. Den Abschluss bildete die Erzeugung von verschiedenen Erdbebenverläufen in Abhängigkeit der Bodenprofile und Anwendung auf die Konstruktion, um wiederum den ungünstigsten Fall zu ermitteln.