Phase structure and morphology of wollastonite‐reinforced polypropylene composites modified with SEBS and SEBS‐g‐MA elastomers

Supermolecular structure of isotactic polypropylene/wollastonite/styrenic rubber block copolymers composites were studied as a function of elastomeric poly‐ (styrene‐b‐ethylene‐co‐butylene‐b‐styrene) triblock copolymer (SEBS) and the SEBS grafted with maleic anhydride (SEBS‐g‐MA) content (from 0 to 20 vol%) by optical, scanning, and transmission electron microscopy, wide‐angle X‐ray diffraction and differential scanning calorimetry. Wollastonite particles disturbed the spherulitization of polypropylene matrix. Both elastomers affected the crystallization of polypropylene matrix mainly by solidification effect. Although SEBS‐g‐MA encapsulated wollastonite particles more expressive than SEBS forming thus core‐shell morphology in higher extent, scanning electron micrographs indicated more constrained wollastonite particles in fractured surfaces of composites with SEBS elastomer. Moreover, SEBS‐g‐MA disorientated wollastonite particles and affected reorientation of the polypropylene crystallites stronger than SEBS elastomer. POLYM. ENG. SCI., 47:2145–2154, 2007. © 2007 Society of Plastics Engineers     

User identification approach based on simple gestures

We present an intuitive, implicit, gesture based identification system suited for applications such as the user login to home multimedia services, with less strict security requirements. The term “implicit gesture” in this work refers to a natural physical hand manipulation of the control device performed by the user, who picks it up from its neutral motionless position or shakes it. For reference with other related systems, explicit and well defined identification gestures were used. Gestures were acquired by an accelerometer sensor equipped device in a form of the Nintendo WiiMote remote controller. A dynamic time warping method is used at the core of our gesture based identification system. To significantly increase the computational efficiency and temporal stability, the “super-gesture” concept was introduced, where acceleration features of multiple gestures are combined in only one super-gesture template per each user. User evaluation spanning over a period of 10 days and including 10 participants was conducted. User evaluation study results show that our algorithm ensures nearly 100 % recognition accuracy when using explicit identification signature gestures and between 88 % and 77 % recognition accuracy when the system needs to distinguish between 5 and 10 users, using the implicit “pick-up” gesture. Performance of the proposed system is comparable to the results of other related works when using explicit identification gestures, while showing that implicit gesture based identification is also possible and viable.     

Modeling the influence of network delay on the user experience in distributed home-automation networks

Today’s modern home-automation systems and services (HASS) frequently communicate over public telecommunications networks, such as the Internet. Unfortunately, these communication networks do not usually provide sufficient quality (i.e., a predictable delay), which is generally assured in fieldbus HASS networks. Consequently, the user-perceived quality of experience (QoE) cannot be maintained at a satisfactory level when using different HASS devices communicating over an IP-based network. The data transferred over the Internet can experience a non-negligible delay that can have a considerable influence on the QoE. For this reason, the main goal of our research was to measure the influence of the network delay on a subjective QoE assessment, while interacting with some frequently used HASS tasks. The results show that users are satisfied if the delay is kept below 0.8?s, and that they can tolerate delays of over 2?s (depending on the level of the HASS task interactivity). Since such a user-perceived subjective QoE assessment is both time-consuming and expensive we also propose objective QoE assessment models to represent the influence of network delay on a subjective QoE assessment for various HASS tasks.     

Product identification in industrial batch fermentation using a variable forgetting factor

For reliable operation and the optimization of production, industrial fermentation processes require appropriate tools for monitoring the process in real time. This work presents the structure and operation of a soft sensor for the on-line monitoring of biomass and product concentration during salinomycin and bacitracin fermentation in an industrial, 80-m³ batch reactor; moreover it provides a tool for evaluation of batch production verified in industrial application. The process estimation algorithm consists of decoupled growth and product models, which ensures an unbiased convergence of the estimator and the robustness of the model. The production of secondary metabolites is described with a non-structured model upgraded with a variable forgetting factor that demonstrated a successful estimation of the non-measured parameters and states of this highly interactive and interlinked system with complex dynamics. The possibility of using various input signals in product identification yields independent soft sensors. This serves to improve the reliability of the predictions, mutual sensor control and enables the detection of irregularities in the fermentation process before the broth becomes useless.     

Interactive TV user interfaces: how fast is too fast?

The analysis presented in this paper is the search for optimal scrolling speeds of the user interface for interactive TV (iTV) navigation. The most popular navigation techniques for browsing through user interfaces usually incorporate scrolling. Furthermore, the latest set-top-boxes have enough processing power to support very fast scrolling, not only for texts, but also for photographs and other elements. We designed and performed an experiment to measure the optimal scrolling speed for different activities on a user interface. We found that the optimal speed depends on the type and complexity of the navigational elements (like text or graphics). We discovered that less-complex elements, such as numbered TV-channel names, tolerate much higher scrolling speeds than more-complex elements, such as graphical elements like movie posters. We also analyzed the impact of the direction of navigation (vertical, horizontal) on the optimal speeds and the results show no major impact on the graphical elements, while for the text elements the difference is obvious. The results of this study can improve the usability of the horizontal and vertical navigation techniques in modern iTV navigation.     

Superbiphilic Laser-Microengineered Surfaces with A Self-Assembled Monolayer Coating for Exceptional Boiling Performance

The rapid advancement of engineering systems has spurred the search for innovative thermal management solutions. Boiling, as a phase-change heat transfer method, has shown promise in heat dissipation, but non-functionalized surfaces struggle with increasing cooling demands. To improve heat dissipation efficiency across different heat loads, functionalized surfaces with tailored wettability have been proposed. Separately, superhydrophilic and superhydrophobic surfaces each offer benefits and drawbacks in boiling applications but combining them on a single “biphilic” surface simultaneously harnesses their advantages. In this study, laser-functionalized copper surfaces with spatially tailored wettability are developed by combining two-step laser texturing with a self-assembled monolayer coating, while focus is placed on the impact of the size and pitch of superhydrophobic spots. The developed functionalized surfaces exhibit exceptional boiling performance with heat transfer coefficients up to 299 kW m⁻² K⁻¹, a 434% enhancement over untreated surfaces. Optimal ratios of superhydrophilic and superhydrophobic areas and optimal spot pitch are identified. Additionally, varying behavior at different heat flux levels is observed, emphasizing the importance of considering thermal loads when determining the optimal surface pattern. This advancement in performance, along with the rapid and cost-effective functionalization process, represents a significant breakthrough for enhanced thermal management applications.     

Determination of Valence States of Chromium in Calcium Chromates by Using X-ray Absorption Near-Edge Structure (XANES) Spectroscopy

Calcium chromates with the empirical formulas Ca₁₀Cr₆−O₂₅, Ca₃Cr₂O₈, and Ca₅Cr₃O₁₂, which form at temperatures >900°C at CaO:Cr₂O₃ molar ratios of 3 in an oxidation atmosphere have been synthesized in the pure state. X-ray absorption near-edge structure (XANES) spectroscopy has been used to determine the average valence state of chromium in the samples. The presence of unusual chromium valence states, 4+ and 5+, which was proposed via X-ray diffractometry studies, is strongly supported.     

Phase relations and optoelectronic characteristics in the NdVO4–BiVO4 system

Studies performed on the NdVO₄–BiVO₄ system showed the existence of the Bi_xNd_1?xVO₄ homogeneity range for x ? 0.49(1). Extended X-ray absorption fine structure and X-ray diffraction analyses confirmed that Bi³⁺ is incorporated onto the Nd site in the NdVO₄ crystal structure with some distortion of the local structure. Surprisingly, the unit cell volume decreases with the increase in the content of the larger Bi³⁺ ion. On the other side of the NdVO₄–BiVO₄ system, Nd³⁺ does not enter the BiVO₄ structure but forms the NdVO₄-based secondary phase. Ultraviolet–visible spectroscopy showed that the band gap of NdVO₄ can be reduced to below 3.1 eV by the Bi doping. New emissions that do not exist for NdVO₄ have been found in the 650–675 nm range of Bi_xNd_1?xVO₄ photoluminescence spectra. The observed chemical and optoelectronic properties were explained on the basis of the hybridization of Bi 6s² and O 2p orbitals.