Solubilisation of dyes by surfactant micelles. Part 3; A spectroscopic study of azo dyes in surfactant solutions†

A spectroscopic study (UV–vis and adsorption) has been made of the interactions of select model azo dyes with a range of surfactant types or their mixtures both above and below their respective critical micelle concentrations. All surfactants inhibit adsorption of the dyes to cotton above their critical micelle concentrations due to incorporation in micelles. However, formation of 1;1 complexes between dyes and cationic or zwitterionic surfactants in sub‐micellar regions results in enhanced deposition on cotton. It is shown that attractive or repulsive electrostatic interactions play a key role in dye binding to micelles. Unusually, spectra of complexes formed between the dye and cationic surfactant are typical of those of the azo tautomeric form as opposed to the hydrazone form that is prevalent in aqueous media. Addition of anionic surfactant to micellar solutions of nonionic or zwitterionic surfactants results in successive displacement of dye from the respective micelles, i.e. binding is competitive.     

Einlagerungen und Austausch von Linolsäure im Körperfett von Broilern bei zeitlich begrenzter Aufnahme verschiedener Öle und Fette

Deposition and Exchange of Linoleic Acid in Depot Fat of Broilers During the Uptake of Various Oils and Fats for Limited Periods The fat quality of slaughtered broiler bodies is mainly determined by two parameters, on the one hand by the viscosity, whose decrease leads to increased losses in body fat during the slaughtering process, on the other hand by the oxidation stability, whose deterioration makes the slaughtered body not eatable. Both parameters are determined by the share of polyen acids, above all of linoleic acid, in vegetable oils. As the fatty acid pattern of the body fat depends in a high degree on the feed fat and broiler rations contain 8–10% fat, the composition of the additional fat is of significant importance. A feed fat with high contents of long chained, saturated fatty acids causes, however, a smaller utilization for chicken in the first 3–5 weeks of life. Both demands, a sufficient viscosity or oxidation stability and a good utilization, lead to the reflection to feed first a high unsaturated vegetable oil and to change during the further fattening period to an animal fat. A corresponding test was carried out with 156 male broilers. Group 1 got throughout the feeding time sunflower oil, group 6 got lard, the other groups underwent a change in feed from sunflower oil to lard, each shifted for one week. During the weekly slaughters abdominal fat was removed for the investigation of fatty acid pattern and iodine value. Feed uptake, increase in weight and feed utilization showed no significant differences. The content of linoleic acid amounted on the 43th day of life in group 1 to 59%, in group 6 to 14%. In the groups with weekly changes the following data were found: group 2: 31.6% (22nd day of life), 19.3% (28th day of life), 17.8% (36th day of life), 16.6% (43rd day of life); group 3: 35.0% (28th day of life), 25.3% (36th day of life), 21.1% (43rd day of life); group 4: 39.4% (36th day of life), 28.7% (43rd day of life); group 5: 42.7% linoleic acid (43rd day of life). After the change to the ration with lard the share of linoleic acid in the abdominal fat diminished significantly. This decrease was the more lower, the later the change in feed took place. The low content of linoleic acid in group 6 was not achieved by any other test group. The determination of the iodine value led to corresponding results.     

Structure-activity relationship in Sb-V-oxide catalysts for the direct synthesis of acrylonitrile from propane

The structure/composition and catalytic behavior in propane ammoxidation to acrylonitrile of Sb-V-oxides prepared by a novel precipitation—deposition method is reported and the nature of the active components in these catalysts is discussed. Results suggest that the active phase for the selective synthesis of acrylonitrile from propane is a trirutile-like V-antimonate with Sb⁵⁺-oxide supported on it. Vanadium plays a catalytic role in the selective activation of propane and reoxidation of antimony, but when present in large amounts on the surface catalyzes the unselective NH₃ → N₂ conversion with a lowering in acrylonitrile selectivity. -Sb₂O₄ is instead a side phase, with a marginal or negligible role in the catalytic behavior.     

Assessment of data and parameter uncertainties in integrated water-quality model

In integrated urban drainage water quality models, due to the fact that integrated approaches are basically a cascade of sub-models (simulating sewer system, wastewater treatment plant and receiving water body), uncertainty produced in one sub-model propagates to the following ones depending on the model structure, the estimation of parameters and the availability and uncertainty of measurements in the different parts of the system. Uncertainty basically propagates throughout a chain of models in which simulation output from upstream models is transferred to the downstream ones as input. The overall uncertainty can differ from the simple sum of uncertainties generated in each sub-model, depending on well-known uncertainty accumulation problems. The present paper aims to study the uncertainty propagation throughout an integrated urban water-quality model. At this scope, a parsimonious bespoke integrated model has been used allowing analysis of the combinative effect between different sub-models. Particularly, the data and parameter uncertainty have been assessed and compared by means of the variance decomposition concept. The integrated model and the methodology for the uncertainty decomposition have been applied to a complex integrated catchment: the Nocella basin (Italy). The results show that uncertainty contribution due to the model structure is higher with respect to the other sources of uncertainty.     

Collective decision with 100 Kilobots: speed versus accuracy in binary discrimination problems

Achieving fast and accurate collective decisions with a large number of simple agents without relying on a central planning unit or on global communication is essential for developing complex collective behaviors. In this paper, we investigate the speed versus accuracy trade-off in collective decision-making in the context of a binary discrimination problem—i.e., how a swarm can collectively determine the best of two options. We describe a novel, fully distributed collective decision-making strategy that only requires agents with minimal capabilities and is faster than previous approaches. We evaluate our strategy experimentally, using a swarm of 100 Kilobots, and we study it theoretically, using both continuum and finite-size models. We find that the main factor affecting the speed versus accuracy trade-off of our strategy is the agents’ neighborhood size—i.e., the number of agents with whom the current opinion of each agent is shared. The proposed strategy and the associated theoretical framework can be used to design swarms that take collective decisions at a given level of speed and/or accuracy.     

Walking on Data Words

Data words are words with additional edges that connect pairs of positions carrying the same data value. We consider a natural model of automaton walking on data words, called Data Walking Automaton, and study its closure properties, expressiveness, and the complexity of some basic decision problems. Specifically, we show that the class of deterministic Data Walking Automata is closed under all Boolean operations, and that the class of non-deterministic Data Walking Automata has decidable emptiness, universality, and containment problems. We also prove that deterministic Data Walking Automata are strictly less expressive than non-deterministic Data Walking Automata, which in turn are captured by Class Memory Automata.     

Frequency domain evaluation of circle criterion,Popov criterion and off-axis circle criterion in the MIMO case

Many control applications can be described as non-linear feedback systems whose stability properties can, for example, be analysed with the circle criterion, the Popov criterion or the off-axis circle criterion. In the SISO case these sector criteria became very popular because of their simple graphic interpretations; the criteria's significance for multivariable feedback systems remained rather poor since there are almost no practicable ways to evaluate them. In this paper the MIMO versions of the three stability criteria are derived using Popov's theory of hyperstability. The main contribution is the presentation of new methods for a frequency domain evaluation of the sector criteria in the multivariable case. The new methods are based on graphic elements: the 'positivity curves'.     

Loss tolerant video streaming authentication in heterogeneous wireless networks

Multicast video streaming in heterogeneous networks undergoes to very different physical constraints, in fact, such networks are characterized by different QoS parameters, involving one or more transcoding process between the sender and the receivers. Video streaming authentication algorithms must be robust to transcoding processes and must guarantee the copyright of the video owner/producer. We propose a real-time video streaming authentication algorithm that can guarantee the copyright of the video owner and that we prove to be robust to packet loss and transcoding processes.     

Special factors and the combinatorics of suffix and factor automata

The suffix automaton (resp. factor automaton) of a finite word w is the minimal deterministic automaton recognizing the set of suffixes (resp. factors) of w. We study the relationships between the structure of the suffix and factor automata and classical combinatorial parameters related to the special factors of w. We derive formulae for the number of states of these automata. We also characterize the languages L_SA and L_FA of words having respectively suffix automaton and factor automaton with the minimal possible number of states.     

Non-trivial solutions for nonlinear fourth-order elastic beam equations

The existence of at least one non-trivial solution to a boundary value problem for fourth-order elastic beam equations, under a non-standard growth condition of the nonlinear term, is established. Our approach is based on a local minimum theorem for differentiable functionals.