Different measures of sensitivity of recipe colour to random and proportional dye concentration error. Part 3: Observed repeatability in regard to predicted sensitivity

The essential question of the paper ‘Can the predicted sensitivity to random and/or proportional dye concentration errors assist in selecting the most repeatable recipes?’ was investigated using the laboratory dyeing of acrylic fabric with basic dyes. When the dye strength errors were not involved, the biggest scattering of the recipe colour in repeated dyeings was observed in the cases of light neutral target colours, where the predicted sensitivity to random concentration errors was also the highest. For a few low‐saturated targets, eight recipes with different predicted sensitivities to random errors were treated. In six cases out of the seven treated, those recipes less sensitive to random concentration errors generally performed better than the more sensitive ones, but the correlation was rather weak. For those cases when the dye strength errors were included, experiments were also carried out with several different recipes for a neutral medium‐lightness target colour.     

Characteristics and Formation Mechanism of BaTiO3 Powders Prepared by Twin-Fluid and Ultrasonic Spray-Pyrolysis Methods

Spherical fine (micrometer and submicrometer in size) homogeneous BaTiO₃ powders were synthesized from ethanol: water solutions of BaCl₂ and TiCl₄ using the spray-pyrolysis technique. Two different atomizers—twin-fluid and ultrasonic, with a resonant frequency of 2.5 × 10⁶ Hz—were used for mist generation. Hollow spherical particles containing a certain amount of unreacted BaCl₂ phase and having a mean particle diameter of 2.5 μm were obtained at 1173 K using a twin-fluid atomizing system. Decomposition of precursors and their transition to the cubic BaTiO₃ phase occurred, even at 973 K in the case of the ultrasonic atomizing system. For the initial droplet size of 2.2 μm and residence time of ∼60 s, spherical BaTiO₃ particles with the mean particle diameter of 0.53 μm were obtained. A BaTiO₃ formation mechanism has been proposed as a reaction between TiO₂ and BaCl₂ rather than a reaction of oxides.     

Microstructural and Tribological Properties of A356 Al–Si Alloy Reinforced with Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Particles

In the present study, the effect of the Al₂O₃ particles (average size of 12 μm, 3 and 10 wt.%) reinforcement on the microstructure and tribological properties of Al–Si alloy (A356) was investigated. Composites were produced by applying compocasting process. Tribological properties of unreinforced alloy and composites were studied, using pin-on-disc tribometer, under dry sliding conditions at different specific loads and sliding speed of 1 m/s. Microhardness measurements, optical microscope and scanning electron microscope were used for microstructural characterization and investigation of worn surfaces and wear debris. During compocasting of A356 alloy, a transformation from a typical dendritic primary α phase to a non-dendritic rosette-like structure occurred. Composites exhibited better wear resistance compared with unreinforced alloy. Presence of 3 wt.% Al₂O₃ particles in the composite material affected the wear resistance only at specific loads up to 1 MPa. The wear rate of composite with 10 wt.% Al₂O₃ particles was nearly two order of the magnitude lower than the wear rate of the matrix alloy. Dominant wear mechanism for all materials was adhesion, with others mechanisms: oxidation, abrasion and delamination as minor ones.     

On Modeling and Verification of Temporal Constraints in Production Workflows

The dynamic nature of events, in particular business processes, is a natural and accepted feature of today’s business environment. Therefore, workflow systems, if they are to successfully model portions of the real world, need to acknowledge the temporal aspect of business processes. This is particularly true for processes where any deviation from the prescribed model is either very expensive, dangerous or even illegal. Such processes include legal processes, airline maintenance or hazardous material handling. However, time modeling in workflows is still an open research problem. This paper proposes a framework for time modeling in production workflows. Relevant temporal constraints are presented, and rules for their verification are defined. Furthermore, to enable visualization of some temporal constraints, a concept of “duration space” is introduced. The duration algorithm which calculates the shortest/longest workflow instance is presented. It is a generalization of two categories of algorithms: the shortest-path partitioning algorithm and the Critical Path Method (CPM). Based on the duration algorithm, the verification algorithm is designed to check the consistency of introduced temporal constraints.     

Soft magnetic properties,magnetoimpedance and torsion-impedance effects in amorphous and nanocrystalline FINEMET alloys: Comparison between ribbons and wires

In this paper, we proposed ab initio calculation of hopping parameters for La₂CuO₄. The Wannier-function projection procedure of obtaining a small Hamiltonian in real space for different sets of bands of interest was used. The importance of taking into account Cu \(d_{3z^2 - r^2 } \) and apical O_a p _z orbitals is shown. The parameters obtained are used to calculate the band structure of undoped La₂CuO₄ in the framework of the multiband p-d model in the regime of strong electron correlations.     

Biodiesel production by ultrasound-assisted transesterification: State of the art and the perspectives

In the present paper state-of-the art and perspectives of ultrasound-assisted (UA) biodiesel production from different oil-bearing materials using acid, base and enzyme catalysts are critically discussed. The ultrasound action in biodiesel production is primarily based on the emulsification of the immiscible liquid reactants by microturbulence generated by radial motion of cavitation bubbles and the physical changes on the surface texture of the solid catalysts generating new active surface area. The importance of ultrasound characteristics and other process variables for the biodiesel yield and the reaction rate is focused on. UA transesterification is compared with other techniques for biodiesel production. Several different developing methods reducing the biodiesel production costs such as the optimization of process factors, the development of the process kinetic models, the use of phase transfer catalysts, the application of the continuous process, the design of novel types of ultrasonic reactors and the in situ ultrasound application in transesterification of oily feedstocks are also discussed.     

A reusable, low-profile, cryogenic wire seal

We describe the design of a reusable indium wire seal which has a small profile and is leak tight to better than 1×10^-10 std. cc/s from room temperature down to ≈. The pressure necessary to deform the indium wire o-ring is provided by a screw-cap mating to threads on the outside of the cylindrical volume to be sealed.     

Influence of T4 Heat Treatment on Tribological Behavior of Za27 Alloy Under Lubricated Sliding Condition

The effects of heat treatment on the microstructure, hardness, tensile properties, and tribological behavior of ZA27 alloy were examined. The alloys were prepared by conventional melting and casting route. The heat treatment of samples included the heating up to 370 °C for 3 or 5 h, quenching in water, and natural aging. Lubricated sliding wear test were conducted on as-cast and heat-treated ZA27 samples using block-on-disc machine. The friction and wear behavior of alloys were tested in contact with steel discs using combinations of three levels of load (10, 30, and 50 N) and three levels of linear sliding speeds (0.26, 0.50, and 1.00 m/s). To determine the wear mechanisms, the worn surfaces of the samples were examined by scanning electron microscopy (SEM). The heat treatment resulted in reduction in the hardness and tensile strength but increase in elongation. The heat-treated alloy samples attained improved tribological behavior over the as-cast ones, under all combinations of sliding speeds and contact loads. The rate of improvement increased with duration of solutionizing process before quenching in water. Obtained tribological results were related to the effects of heat treatment on microstructure changes of alloy.     

How the online social networks are used: dialogues-based structure of MySpace

Quantitative study of collective dynamics in online social networks is a new challenge based on the abundance of empirical data. Conclusions, however, may depend on factors such as user''s psychology profiles and their reasons to use the online contacts. In this study, we have compiled and analysed two datasets from MySpace. The data contain networked dialogues occurring within a specified time depth, high temporal resolution and texts of messages, in which the emotion valence is assessed by using the SentiStrength classifier. Performing a comprehensive analysis, we obtain three groups of results: dynamic topology of the dialogues-based networks have a characteristic structure with Zipf''s distribution of communities, low link reciprocity and disassortative correlations. Overlaps supporting ‘weak-ties’ hypothesis are found to follow the laws recently conjectured for online games. Long-range temporal correlations and persistent fluctuations occur in the time series of messages carrying positive (negative) emotion; patterns of user communications have dominant positive emotion (attractiveness) and strong impact of circadian cycles and interactivity times longer than 1 day. Taken together, these results give a new insight into the functioning of online social networks and unveil the importance of the amount of information and emotion that is communicated along the social links. All data used in this study are fully anonymized.