h-BN/Ru(0 0 0 1) nanomesh: A 14-on-13 superstructure with 3.5 nm periodicity

The structure of epitaxially grown hexagonal boron nitride (h-BN) on the surface of a Ru(0 0 0 1) single crystal was investigated using surface X-ray diffraction, which showed the system to form a commensurate 14-on-13 superstructure. This result disagrees with previous reports on superstructures of the same system and arguments based on simple thermal expansion coefficient calculations. We argue that the larger observed superstructure forms because of the strong bonding of h-BN to Ru. In comparison to h-BN/Rh(1 1 1) it can accommodate more induced lateral in-plane strain- or lock-in energy over larger regions (referred to as the holes) within the superstructure, which itself can consequently become larger.     

Improving biorefinery planning: Integration of spatial data using exact optimization nested in an evolutionary strategy

Biorefineries can provide a product portfolio from renewable biomass similar to that of crude oil refineries. To operate biorefineries of any kind, however, the availability of biomass inputs is crucial and must be considered during planning. Here, we develop a planning approach that uses Geographic Information Systems (GIS) to account for spatially scattered biomass when optimizing a biorefinery’s location, capacity, and configuration. To deal with the challenges of a non-smooth objective function arising from the geographic data, higher dimensionality, and strict constraints, the planning problem is repeatedly decomposed by nesting an exact nonlinear program (NLP) inside an evolutionary strategy (ES) heuristic, which handles the spatial data from the GIS. We demonstrate the functionality of the algorithm and show how including spatial data improves the planning process by optimizing a synthesis gas biorefinery using this new planning approach.     

Particle-like platonic solutions in scalar gravity

We construct globally regular gravitating solutions, which possess only discrete symmetries. These solutions of Yang–Mills-dilaton theory may be viewed as exact (numerical) solutions of scalar gravity, by considering the dilaton as a kind of scalar graviton, or as approximate solutions of Einstein–Yang–Mills theory. We focus on platonic solutions with cubic symmetry, related to a rational map of degree N=4$N=4$. We present the first two solutions of the cubic N=4$N=4$ sequence, and expect this sequence to converge to an extremal Reissner–Nordström solution with magnetic charge P=4$P=4$.     

Orbits in the field of a gravitating magnetic monopole

Orbits of test particles and light rays are an important tool to study the properties of space-time metrics. Here we systematically study the properties of the gravitational field of a globally regular magnetic monopole in terms of the geodesics of test particles and light. The gravitational field depends on two dimensionless parameters, defined as ratios of the characteristic mass scales present. For critical values of these parameters the resulting metric coefficients develop a singular behavior, which has profound influence on the properties of the resulting space-time and which is clearly reflected in the orbits of the test particles and light rays.     

Stationary Dyonic regular and black hole solutions

We consider globally regular and black hole solutions in SU(2) Einstein–Yang–Mills–Higgs theory, coupled to a dilaton field. The basic solutions represent magnetic monopoles, monopole–antimonopole systems or black holes with monopole or dipole hair. When the globally regular solutions carry additionally electric charge, an angular momentum density results, except in the simplest spherically symmetric case. We evaluate the global charges of the solutions and their effective action, and analyze their dependence on the gravitational coupling strength. We show, that in the presence of a dilaton field, the black hole solutions satisfy a generalized Smarr type mass formula. B. Kleihaus gratefully acknowledges support by the German Aerospace Center. F. Navarro-Lérida gratefully acknowledges support by the Ministerio de Educación y Ciencia under grant EX2005-0078.     

Untersuchungen zur chemischen Bestimmung von Threonin und Serin

Zusammenfassung Die Threonin- bzw. die Threonin und Serinbestimmung auf chemischem Wege werden hinsichtlich der beiden wichtigsten Verfahren, nämlich der Oxydation mit Bleitetraacetat und mit Perjodsäure, vergleichend überprüft. Beide Methoden arbeiten, insbesondere nach Einführung einer für die Serinoxydation vorgeschlagenen Abänderung, recht genau. Für die Untersuchung von Aminosäuregemischen oder Eiweißhydrolysaten ist aus erörterten und überprüften Gründen die Perjodat-Oxydation vorzuziehen.     

Zusammenhang von elektrochemischkonstitutivem und kolloidem Aufbau reinster Farbsole

Zusammenfassung 1. Es werden mittels Elektrodialyse und Elektrodekantierung die hochgereinigten azidoiden blauen Farbsole aus Congorot, Congorubin, Congokorinth G, Benzopurpurin 4 B und Chicagoblau 6 B sowie zum Vergleich das basische Farbsol von Nachtblau hergestellt. 2. Diese Sole werden in bezug auf ihre elektrochemischkonstitutiven sowie Assoziations?nderungen durch Bestimmung ihrer thermischen Leitf?higkeitsabh?ngigkeit (x, t-Kurve) und deren Reversibilit?t sowie der Verdünnungs?nderung ihrer molekularen Leitf?higkeiten μ untersucht. 3. Es wird gezeigt, wie bei den genannten azidoiden Farbsolen, die s?mtliche Aminosulfos?uren darstellen, die Assoziationskr?fte mit der inneren Salzbildung wachsen und wie andererseits mit der Zunahme der polaren sauren Gruppen infolge der thermischen oder Verdünnungsaminolyse des inneren Salzes die Desassoziation erh?ht wird. Das Nachhinken der Leitf?higkeitswerte beim Wiederabkühlen ist der Ausdruck einer Assoziationshysteresis. Mit der Zeit stellt sich beim Stehen ein Assoziationsgleichgewicht ein. 4. Gegenüber dem Congoblau weisen Congorubin und Congokorinth eine Verminderung um eine NH₂-Gruppe, dagegen eine zus?tzliche OH-Gruppe auf, welche je nach ihrer Stellung den sauren Charakter mehr oder weniger verst?rkt. Die Halbierung der inneren Salzbildung und die Steigerung der Gesamtladung pr?gen sich genau in der zu erwartenden Reihenfolge steigender molekularer Leitf?higkeit und der Desassoziation aus. Auch das Verhalten des azidoiden Benzopurpurin- und Chicagoblausols ist hinsichtlich desx, t-Ganges und der μ-Werte sowie der Kolloid?quivalente durchaus das konstitutiv erwartete. 5. Es lassen sich plausible Modelle des Aufbaues der verschiedenen ionischen Micellen bei den einzelnen Farbsolen aufstellen. 6. Die Beziehungen der Farbsole zu den Seifensolen einerseits und den Proteinsolen andererseits werden kurz er?rtert.     

Method development for the determination of selected pesticides on tobacco by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry

A method was developed for the quantitative determination of alachlor, benalaxyl, clomazone, diflubenzuron, dimethomorph, diphenamid, ethofumesate, metalaxyl, methoprene, metobromuron and piperonyl butoxide on tobacco. The pesticides were extracted with water and methanol from five different types of tobacco. The extracts were purified by partition on an extraction cartridge containing diatomaceous earth. The purified extracts were analysed by reversed-phase high-performance liquid chromatography connected to an atmospheric pressure ionisation–electrospray-triple quadrupole mass spectrometer operating in the positive ion mode. Two different transitions and their relative intensities were monitored for unambiguous identification. All pesticides presented overall recovery rates between 35% and 110%. The trueness is near 100% and the interday precision is below 15%. The limits of quantifications are equal or below the guidance residue levels proposed by the Agrochemical Advisory Committee of CORESTA, an association of organisations having scientific research relative to tobacco.