Flux Jumps and H-T Diagram of Instability for MgB2

We present a study of magneto-thermal instabilities in polycrystalline MgB₂ superconductor, by magnetic hysteresis loop measurements and by investigations of magnetic flux dynamics with a miniature Hall probe. Temperature and magnetic field ranges where the flux jumps may be observed have been determined. On the basis of measurements of the magnetic flux dynamics, an average magnetic diffusivity describing the process of the flux jump is estimated. This parameter is compared with the thermal and magnetic diffusivities calculated on the basis of available data for thermal conductivity, heat capacity and resistivity. It is shown that the estimated value of the field of the first flux jump is influenced significantly by the field dependence of specific heat. In order to explain the observed phenomenon, the temperature reached by the sample during the flux jump at different magnetic fields is calculated.     

Diffusion with simultaneous immobilization in polymer–dye systems. I. Diffusion of the cationic dye anilana red BL in the anionically modified polyester fiber dilana

The diffusion coefficient of the cationic dye Anilana Red BL in the anionically modified polyester fiber Dilana has been calculated regarding a general diffusion-immobilization model. In the model the mobile species are distinguished from the immobilized ones. In computations of Sand's equation and experimentally determined sorption isotherm of the dye in the fiber, the rate-of-dyeing curve and the concentration profiles of the dye in the same fiber were employed. The diffusion coefficient of the mobile species of Anilana Red BL in the fiber is two orders of magnitude higher than the average diffusion coefficient obtained from Hill's equation and the apparent diffusion coefficient calculated by the Boltzmann–Matano method.     

Bioactive compounds in rye flours with different extraction rates

Rye flours with extraction rate of 100% (wholemeal flour), 95% (brown flour), 90% (brown flour) and 70% (light flour) were prepared in order to study the relation between flour extraction rates and content of bioactive compounds. The following compounds were analysed: total phenolic compounds (TPC), total flavonoids (TF), inositol hexaphosphate (IP6), reduced (GSH) and oxidized (GSSG) glutathione, tocopherols (T) and tocotrienols (T3). The reduced/oxidized glutathione status (GSH/GSSG) of the flours was examined as a potential index of flour resistance against oxidative stress. The following observations were made in relation to the flour extraction rates and bioactive compounds contents: (a) milling process caused decrease in content in TPC, TF, IP6, GSH and GSSG, T and T3, (b) the most resistant against oxidation processes were suggested a brown flours, then light and finally wholemeal flour, (c) the ratio of tocotrienols to tocopherols (T3/T) was the highest in rye flours with extraction rate of 100–90% whereas light flour was the poorest source of tocopherols and tocotrienols. The provided data support current trend to increase number of rye products from wholemeal or brown flours.     

Studies of porous polymer gels. I. One-step suspension technique for preparation of moderately crosslinked methacrylic acid gels

A new method of preparation of carboxyl cation exchangers directly from methacrylic acid and divinylbenzene is described. A suspension technique with a concentrated aqueous calcium chloride solution as the water phase was used. n-Octane and toluene were inert diluents of the monomers. The copolymers obtained have high ion-exchange capacity (9.6–10.6 mequ./g) and porous structure.     

Role and distribution of different Ba-containing phases in supported Pt–Ba NSR catalysts

Pt–Ba/MeO (where MeO = Al₂O₃, CeO₂, SiO₂ and ZrO₂) NO _x storage-reduction catalysts with Ba-loading varying from 0 wt.% to 28 wt.% were investigated concerning stability of Ba phases and NO _x storage-reduction efficiency. For Pt–Ba/Al₂O₃ three different Ba-containing phases with different thermal stability are distinguished based on their interaction with the support. The relative concentration of these phases varies with the Ba-loading and NO _x storage tests indicated that the BaCO₃ phase decomposing between 400 °C and 800 °C (LT-BaCO₃) is the most efficient Ba containing phase for NO _x storage. Similar investigations of Pt–Ba catalysts supported on CeO₂, SiO₂ and ZrO₂ showed that the relative amount of LT-BaCO₃ phase depends also on the support material. NO _x storage measurements confirmed a correlation between the concentration of LT-BaCO₃ and NO _x storage efficiency. Basicity and textural properties of the support are identified as crucial parameters for efficient NO _x storage catalysts.     

Probabilistic resource allocation in heterogeneous distributed systems with random failures

The problem of finding efficient workload distribution techniques is becoming increasingly important today for heterogeneous distributed systems where the availability of compute nodes may change spontaneously over time. Resource-allocation policies designed for such systems should maximize the performance and, at the same time, be robust against failure and recovery of compute nodes. Such a policy, based on the concepts of the Derman–Lieberman–Ross theorem, is proposed in this work, and is applied to a simulated model of a dedicated system composed of a set of heterogeneous image processing servers. Assuming that each image results in a “reward” if its processing is completed before a certain deadline, the goal for the resource allocation policy is to maximize the expected cumulative reward. An extensive analysis was done to study the performance of the proposed policy and compare it with the performance of some existing policies adapted to this environment. Our experiments conducted for various types of task-machine heterogeneity illustrate the potential of our method for solving resource allocation problems in a broad spectrum of distributed systems that experience high failure rates.     

Predicting Occupational Coping Responses: The Interactive Effect of Gender and Work Stressor Context.

This study examined whether gender and work stressor context interacted to affect reports of occupational coping strategies. Participants (N=113) were asked to indicate how they would cope with both self-focused (i.e., solitary) and interpersonal (i.e., group) work overload contexts by providing responses to the Cybernetic Coping Scale (J. Edwards & A. J. Baglioni, 1993). Consistent with the hypothesized interaction, male and female participants evidenced similar coping strategies in the self-focused work overload context, whereas female participants showed significantly higher use of coping (T2=.08, p     

Generalized model of vibro-isolation systems with seated human body for single-axis transmission of vibration

A generalized model of vibration isolation systems with a human body in a seated position is developed. The system dynamics is modeled for a single-axis transmission of vibration, that is, longitudinal x, lateral y and vertical z, to limit whole-body vibration exposure. The developed model can be successfully employed to describe the propagation of vibration waves from the source to a vibrating object. The proposed mathematical model can be widely used to protect a human body against vibration.     

The State‐of‐the‐Art in Predictive Visual Analytics

Predictive analytics embraces an extensive range of techniques including statistical modeling, machine learning, and data mining and is applied in business intelligence, public health, disaster management and response, and many other fields. To date, visualization has been broadly used to support tasks in the predictive analytics pipeline. Primary uses have been in data cleaning, exploratory analysis, and diagnostics. For example, scatterplots and bar charts are used to illustrate class distributions and responses. More recently, extensive visual analytics systems for feature selection, incremental learning, and various prediction tasks have been proposed to support the growing use of complex models, agent‐specific optimization, and comprehensive model comparison and result exploration. Such work is being driven by advances in interactive machine learning and the desire of end‐users to understand and engage with the modeling process. In this state‐of‐the‐art report, we catalogue recent advances in the visualization community for supporting predictive analytics. First, we define the scope of predictive analytics discussed in this article and describe how visual analytics can support predictive analytics tasks in a predictive visual analytics (PVA) pipeline. We then survey the literature and categorize the research with respect to the proposed PVA pipeline. Systems and techniques are evaluated in terms of their supported interactions, and interactions specific to predictive analytics are discussed. We end this report with a discussion of challenges and opportunities for future research in predictive visual analytics.     

An alternative formulation of the geometric stiffness matrix for plate elements

A simplified formulation of the geometric stiffness matrix for plate elements is presented. In this formulation the transverse displacement is defined along the element boundary but not for the element interior as with the usual formulation. As such the formulation is particularly suitable for use with hybrid stress or discrete Kirchhoff methods which are also based on boundary approximation of the transverse displacement.

The simplicity, computational economy and accuracy obtained with the formulation compare favorably with the usual order formulation.