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Deammonification is a well-established process for sludge liquor treatment and promising for wastewaters with high nitrogen loads because of its low energy demand compared to nitrification/denitrification. Two wastewaters with high NH4-N concentrations and a rising significance in Germany—pig slurry (12 samples) and condensates from sewage sludge drying (6 samples)—were studied for their deammonification potential. Furthermore, a comprehensive quality assessment is presented. Both wastewaters show a wide range in terms of CODt, CODs, TN and NH4-N, whereby condensates show a greater variability with no direct relation to dryer type or temperature. In the slurries, CODt shows a relative standard deviation of 106% (mean 21.1 g/L) and NH4-N of 33% (mean 2.29 g/L), while in condensates it reaches 148% for CODt (mean 2.0 g/L) and 122% for NH4-N (mean 0.7 g/L). No inhibition of ammonium-oxidizing-bacteria was detected in the slurries, while two out of five condensates showed an inhibition of >40%, one of >10% and two showed no inhibition at all. Since the inhibition could be avoided by mixing, deammonification can be recommended for condensate treatment. For slurry treatment, the importance of employing some form of solid-liquid-separation as a pretreatment was noted due to the associated COD.

In der letzten Ausgabe hat sich der Autor auf Basis der Schlussantrage der EuGH-Generalanwaltin in den verbundenen Rechtssachen (Rs) C-245/19 und C-246/19 mit der Frage beschaftigt, ob die fehlende Rechtsschutzmoglichkeit bei EU-Amtshilfeersuchen mit Unionsrecht vereinbar ist. Rund drei Monate nach Ergehen der Schlussantrage hat der EuGH mit Urteil v. 6.10.2020 entschieden. Der EuGH ist den Schlussantragen nur zum Teil gefolgt. Im nachstehenden Beitrag werden die Kernaussagen des EuGH-Urteils zusammengefasst, gewurdigt und die Auswirkungen auf die osterreichische Rechtslage dargestellt.

In den letzten Jahren ist eine rasante Entwicklung bei zwischenstaatlichen Amtshilfen in Abgabensachen zu beobachten. Jeder Informationsaustausch ist dabei zwangslaufig mit einem Rechtseingriff verbunden. Eine Rechtsschutzmoglichkeit ist nach derzeit geltender osterreichischer Rechtslage nicht vorgesehen. Der nachfolgende Beitrag befasst sich ua mit der Frage, ob dies angesichts der jungst ergangenen Schlussantrage der EuGH-Generalanwaltin in den verbundenen Rechtssachen C-245/19 und C-246/19 den unionsrechtlichen Vorgaben entspricht.

Die Entscheidung des Bundesfinanzgerichts (BFG) behandelt die Zurechnung von Kapitaleinkunften bei einer liechtensteinischen Stiftung. Anders als die bisher zu liechtensteinischen Stiftungen ergangenen Gerichtsentscheidungen betrifft die Entscheidung des BFG diesmal die Erben-Generation. Das BFG hat in seiner Entscheidung die „steuerliche Intransparenz“ der liechtensteinischen Stiftung festgestellt und eine Einkunftezurechnung bei der Begunstigten verneint.

A star enshrouded in a Dyson sphere with high covering fraction may manifest itself as an optically subluminous object with a spectrophotometric distance estimate significantly in excess of its parallax distance. Using this criterion, the Gaia mission will in coming years allow for Dyson-sphere searches that are complementary to searches based on waste-heat signatures at infrared wavelengths. A limited search of this type is also possible at the current time, by combining Gaia parallax distances with spectrophotometric distances from ground-based surveys. Here, we discuss the merits and shortcomings of this technique and carry out a limited search for Dyson-sphere candidates in the sample of stars common to Gaia Data Release 1 and RAVE Data Release 5. We find that a small fraction of stars indeed display distance discrepancies of the type expected for nearly complete Dyson spheres. To shed light on the properties of objects in this outlier population, we present follow-up high-resolution spectroscopy for one of these stars, the late F-type dwarf TYC 6111-1162-1. The spectrophotometric distance of this object is about twice that derived from its Gaia parallax, and there is no detectable infrared excess. While our analysis largely confirms the stellar parameters and the spectrophotometric distance inferred by RAVE, a plausible explanation for the discrepant distance estimates of this object is that the astrometric solution has been compromised by an unseen binary companion, possibly a rather massive white dwarf ($\approx 1\ M_\odot$). This scenario can be further tested through upcoming Gaia data releases., Comment: 9 pages, 4 figures, v.2: ApJ, in press

Monte Carlo simulation of freely jointed off-lattice chains with variable bond length is usually done with local random displacements of beads and with reptation moves (displacements of a bead along a chain). In dense systems, the acceptance ratio of reptations decreases strongly with density. We discuss versions of reptation moves, which are effective in dense systems. The idea, which comes from lattice systems, is to use a pseudovacancy (walker), which has the same size as a bead of a chain. The walker is attached to a neighbor chain and then another bead of that chain is cleaved. This is equivalent to a reptation move and a nonlocal displacement of the walker and since no free volume is needed, the move can be used with advantage in dense systems. A related technique are cooperative motions, which were introduced by T. Pakula for lattice models, where several chains change their conformation concomitantly. Such cooperative loops are implemented in the Monte Carlo algorithm by creating a temporary walker by cleaving a bead from a chain, moving it with reptations and finally annihilating the walker by attaching it to the same chain it was cleaved from. These moves and the condition of detailed balance are discussed in detail. As an example, we study the integrated autocorrelation time τ int for the radius of gyration for a two-dimensional system. For reduced densities larger than 0,4, we find that with standard reptations and local bead displacements Tint increases strongly with density. If reptations with either a permanent or a temporary walker are used in addition to local moves, the integrated autocorrelation time changes only very little with density and very dense systems can still be simulated efficiently.

The dynamics of the symmetrically constrained Ising spin chain, or symmetric one-spin facilitated kinetic Ising model, is investigated both by Monte Carlo simulation and by analytical mode-expansion methods. We confirm Fredrickson's argument that at low concentration of the facilitating up spins, the dynamics is governed by the diffusion of isolated up spins, but only for very low up-spin concentrations c ≤ 10 −3 . An adequate analytical treatment is obtained by a three-spin approximation, which describes the diffusion of pairs of isolated up spins.

A dense system of dimers on hypercubic lattices is studied with Monte Carlo simulation, where dimers are displaced concomitantly in loops. A mixture of A- and B-dimers with an attractive interaction of strength unity between identical nearest neighbors, where the number of A- or B-dimers can fluctuate but not their sum, undergoes an Ising-type demixing transition of second order when changing the temperature. The transition temperatures are Tc ∾ 1.71 and Tc ∾ 3.91 on a square and cubic lattice, respectively. A system of co-dimers, where a co-dimer consists of an A- and a B-subunit, with an attractive interaction between identical nearest neighbors, undergoes a microphase separation, where the dimers orient into a lattice direction. In two dimensions the transition at Tc ∾ 0.831 is of second order and the critical exponents ν ∾ 0.67 and β ∾ 0.11, determined by finite size scaling, do not belong to the Ising class. In three dimensions the transition at Tc ∾ 1.15 is first order. Random error estimates are better than 1% for the critical temperatures, about 2–4% for ν and about 10% for β. However, no estimation of possible systematic errors due to corrections to finite size scaling has been attempted.

We present a class of kinetic Ising models with a directed constraint, which exhibit a dynamocal phase transition at a critical up-spin concentration. At lower up-spin concentrations a non-ergodic state exists, for which the fraction of permanently blocked spins plays the role of an order parameter. The spin autocorrelation function has been calculated by Monte Carlo simulation for two particular models: One for the square lattice, with the constraint that the neighboring spins in the north and in the east are up, and one for a Cayley tree with branching ratio 2, where both neighbors above a given spin must be up. The transition is of second order, and the integrated autocorrelation time diverges on both sides of the transition. The models define a distribution of blocking lengths, which can be calculated analytically for the Cayley tree. We conjecture that this length distribution is related to the autocorrelation time by a dynamic critical exponent, which is numerically estimated for small lattices up to a length 11 to be about 5 and 2.7 for the two models, respectively.

On a cubic and a square lattice, the statics and dynamics of a cyclic random walk in a regular network of uncrossable obstacles is investigated with a Monte Carlo algorithm where the chain moves along its contour by defect diffusion. For chain lengths of N=16 to N=128, the root‐mean‐square radius of gyration is found to vary as about N0.33 for both lattices. The exponent is decreasing with increasing chain length. For the same range of chain lengths, the center‐of‐mass diffusion coefficient is found to vary as about N−2.1 and N−1.9, and the integrated autocorrelation time of the radius of gyration is found to vary as about N2.7 and N2.6 for cubic and square lattices, respectively. The cyclic chain diffuses by tube leakage, with a diffusion coefficient which is similar to that of a linear random walk chain in a network.

The two‐spin–facilitated kinetic Ising model, or Fredrickson–Andersen model, in two dimensions is investigated, where down‐spins are energetically favored over up‐spins due to a suitably oriented magnetic field and the only interaction between spins is a dynamic constraint which allows any spin to flip only if it has at least two nearest up‐spin neighbors. From Monte Carlo simulations it is known that the model exhibits glasslike behavior where the autocorrelation time of a spin as a function of temperature is well described by the Adam–Gibbs expression. Due to the dynamic constraint, the state space is divided into nonconnected partitions the most important of which is the high temperature partition which includes the all‐spins‐up state. A proof given earlier by Fredrickson and Andersen is completed, which states that for infinitly large lattices and for a temperature larger than zero, the probability that a randomly picked state is part of the high temperature partition approaches unity. It is also shown that the system is ergodic, i.e., that no glass transition may occur at a temperature larger than zero. These results hold also for the model in higher dimensions than two and for the three‐spin–facilitated kinetic Ising model in three dimensions. It is suggested that the model equilibrates by cooperative diffusion of a critical droplet of up‐spins.

The integrated decay times for correlations of the end‐to‐end vector of random walk chains of length N are well known to be proportional to N2 and N3 for the Rouse and the reptation models, respectively. For subchains of length n situated in the center and at the end of a chain, respectively, these times are about nN and n2 in the Rouse model and nN2 and n2N in the reptation model if n≪N holds. For a random walk chain in a network of obstacles which moves along its contour by defect diffusion with Monte Carlo simulations, the autocorrelation time for the end‐to‐end vector and the disentanglement time for the primitive path are found to vary as about N3.5 and N3.7, respectively, for chain lengths varying from 15 to 63. The curvilinear diffusion coefficient varies as about N−1.2 and the center‐of‐mass diffusion coefficient varies as about N−2.4. The integrated autocorrelation times of small subchains vary with n/N also faster than predicted by the reptation model.

A Monte Carlo algorithm for hypercubic lattices is investigated that combines end and kink reptations with local dynamic motions. It can be used for linear chains, for rings, and for the equilibration of the arms of star polymers. The algorithm fulfils the condition of detailed balance, and it is ergodic for a single linear chain. For the special case of a cyclic chain in two dimensions, a proof of ergodicity is also given. The statistical properties of the algorithm are discussed and, as examples, chain dimensions of linear and cyclic chains are computed

Polymer chain models on quadratic, cubic, triangular, and face‐centered cubic lattices at volume fractions near unity are simulated with a Monte Carlo algorithm which transports beads from kinks or chain ends along the chain contour to another position of the chain by a slithering motion of the intervening chain part. Special cases are the slithering snake motion where the whole chain takes part in the slithering motion and a conformation change of a kink or an end group. For dense systems it is found that this algorithm is much more efficient than the slithering snake algorithm or algorithms which use only local motions. It can be used with good efficiency even for systems at a volume fraction of unity by moving chain parts collectively (collective motion algorithm). The computed chain dimensions agree with data obtained from other algorithms and with literature data.

A fast Monte Carlo integration algorithm with varying time step is described for cooperative binding of ligands of arbitrary length to a one-dimensional lattice. This algorithm is particularly suitable for strongly cooperative or anticooperative systems, i.e., when the time scales for different kinetic events are very different. As an application, the kinetics of a bimodal two-ligand system are briefly discussed.

At present the collective motion algorithm is the only Monte Carlo technique which allows the simulation of monodisperse polymer melts on a lattice at a volume fraction of unity. Here we describe the algorithm in detail and show that it fulfils the condition of detailed balance. It yields chain dimensions which are slightly smaller than chain dimensions obtained for polydisperse systems or for systems at volume fractions smaller than unity, as expected. The computational expense to obtain an independent sample containing a constant number of chains increases as about the 3.6th power of chain length.

By use of pseudokinetic rearrangements, the interface between two polymer melts that are mutually repulsive but otherwise identical is simulated on a five-way cubic lattice at a total volume fraction of unity. The position of the interface, which has been deliberately located at z=0, remains stable if the repulsion energy is large enough and if it is ensured in the algorithm that the ratio of the volume fractions of the two polymers is distributed sharply about unity. Conventional periodic boundary conditions were used in the x and y direction, while antiperiodic boundary conditions were introduced at z=−l z /2 and z=+l z /2 (l z being the lattice dimension in the z direction). At such an antiperiodic boundary one kind of chain is continued as the other kind if the chain stretches across that boundary and nearest neighbors are counted as the same if they are different (and as different if they are the same), thus avoiding the need for a hard boundary. The interface appears to be thicker and local energies are lower than predicted by mean field theories. At the interface it is seen that chain ends and, in case of polydisperse polymers, smaller chains migrate preferentially into the opposite melt while chain dimensions perpendicular to the interface are decreased

Extended Abstract: Glass forming organic liquids and polymers exhibit long range density fluctuations with correlation length ξ in the range of 10–300 nm at temperatures above Tg (1 - 6). This follows from dynamic and static light scattering experiments revealing some unexpected features, which cannot be explained on the basis of conventional liquid state theories: (i) In static light scattering the intensity I(q 0) is no longer proportional to the isothermal compressibility, (ii) This excess scattering Iexc shows a strong q-dependence (q = (4π/Λ.)sin(θ/2)) corresponding to a correlation length ξ in the above mentioned range, (iii) The Landau-Placzek ratio IRayleigh/2IBrillouin is much too high compared with the results of light scattering theories, (iv) In photon correlation spectroscopy a new ultraslow hydrodynamic mode (Γ ˜ q2) is detected with relaxation rates Γ about 10−6 to 10−9 lower than those of the α-process at a given temperature. In order to explain these observations, a two-state fluid model is proposed, which starts from the coexistence of “liquid-like” and “aperiodic solid-like” regions within the liquids. Such ideas have been discussed many times before, so for example A.R. Ubbelohde (7) speculates about “anticrystalline” clusters in liquids. Molecular dynamics simulations of atomic liquids showed that long range orientational fluctuations appear upon supercooling (8). A preferred icosahedral ordering is observed (9) and the number of icosahedral clusters increases with decreasing temperature (10). In connection with the interpretation of the dynamics of supercooled liquids different “two-state” models have been proposed (11 - 15). For the explanation of the light scattering results we propose that the molecules in the different dynamic states (“liquid” or “solid”) aggregate during annealing of the liquid at temperatures above Tg. Experiments showed that the equilibration times can be rather long (3 - 5), but nevertheless the liquids exhibiting long range density fluctuations are in the state of lowest free energy. We claim that our observations are the first experimental proof of the existence of such different dynamic states, which have been discussed many times before. The extended secondary clusters can also be detected by ultra small angle X-ray scattering.

Etude des relations d'echelle de la distance bout a bout efficace et du rayon de giration efficace d'un polymere fondu athermique sur un reseau quadratique a une fraction volumique de 1 en utilisant les rearrangements de rupture de liaison pseudocinetiques. Discussion de l'influence sur les dimensions de la chaine des schemas cinetiques et des contraintes de longueur de chaine

Propagating chemical pulses are observed in the illuminated dimerization reaction of S2O6F2 when this bistable system is suitably perturbed. The dependence of the speed of propagation on incident laser power and the temporal evolution of the absorption profile along the laser beam are measured. The results compare well with calculations based on a previously developed model. The propagating chemical pulse is compared to chemical waves in an excitable medium.

Nearest-neighbor cooperative binding of a ligand covering n sites and binding with equilibrium constant K and cooperativity factor omega to a large molecule with m binding sites (m much greater than n omega, n/omega) can be approximately described by a Gaussian distribution P(q-qmax), where q is the number of ligands bound and qmax the most probable value of q. The variance of the Gaussian is equal to the derivative dqmax/d ln(L), where L is the free ligand concentration. This variance, sigma 2, is a complicated function of qmax. However, in the limits of very large cooperativity, omega much greater than 1, very large anticooperativity, omega much less than 1, or noncooperativity, omega = 1, simpler expressions for sigma 2 can be given. For qmax = m/(n + 1), where the most probable number of bound ligands equals the number of free binding sites, sigma 2 has a particularly simple form: sigma 2 = 2m omega 1/2/(n + 1)3. The Gaussian and the infinite lattice approximations for the average number of ligands bound are good approximations only if sigma is much smaller than the number of binding sites. The variance may therefore provide an easy check on the validity of the infinite lattice approximation, which is commonly used to analyze experimental binding data.

Modification de la methode de calcul de Flory en ne considerant que le terme de volume exclu et en partant d'une chaine a marche aleatoire persistante (PRW)