Protective coating based on manganese–copper oxide for solid oxide fuel cell interconnects: Plasma spray coating and performance evaluation

A solid oxide fuel cell (SOFC) stack requires metallic interconnects to electrically connect unit cells, while preventing fuel from mixing with oxidant. During SOFC operations, chromia scales continue to grow on the interconnect surfaces, resulting in a considerable increase of interfacial resistance, and at the same time, gaseous Cr species released from the chromia scales degrades the cathode performance. To address these problems, in this study, protective Mn₂CuO₄ coatings are fabricated on metallic interconnects (Crofer 22 APU) via a plasma spray (PS) process. The PS technique involves direct spray deposition of molten Mn₂CuO₄ onto the interconnect substrate and leads to the formation of high-density Mn₂CuO₄ coatings without the need for post-heat-treatment. The thickness, morphology, and porosity of the PS-Mn₂CuO₄ coating are found to depend on the processing parameters, including plasma arc power, gas flow rate, and substrate temperature. The PS-Mn₂CuO₄ coating fabricated with optimized parameters is completely impermeable to gases and has high adhesion strength on the interconnect substrate. Furthermore, no resistive chromia scales are formed at the coating/substrate interface during the PS process. As a result, the PS-Mn₂CuO₄-coated interconnects show a very low area-specific resistance below 10?mΩ?cm² at 800?°C in air and excellent stability during both continuous operation and repeated thermal cycling. This work suggests that an appropriate combination of the material and coating process provides a highly effective protective layer for SOFC interconnects.     

Mobile broadcast services with MIMO antennae in 4G wireless networks

The deployment of wireless data broadcast to empower mobile information services as a resource-conserving means offers significant benefits due to the scalability feature offered by the technology. In this paper, we present a novel and holistic data broadcast management approach in 4 G wireless networks with multiple-input multiple-output (MIMO) antennae. The proposed scheme consists of three elements, namely: (i) broadcast ordering; (ii) Global indexing; and (iii) merging data structure. With the integration of these elements, we expect to obtain substantial efficiency for mobile computing clients when retrieving data on-air. We have experimentally evaluated the performance of the proposed model including comparison with the relevant schemes. The results from the experiments affirm the effectiveness of our proposed approach in respect to minimizing query access time and conserving energy utilization of the clients.     

Trustworthy-based efficient data broadcast model for P2P interaction in resource-constrained wireless environments

In a decentralised system like P2P where each individual peers are considerably autonomous, the notion of mutual trust between peers is critical. In addition, when the environment is subject to inherent resource constraints, any efficiency efforts are essentially needed. In light of these two issues, we propose a novel trustworthy-based efficient broadcast scheme in a resource-constrained P2P environment. The trustworthiness is associated with the peer?s reputation. A peer holds a personalised view of reputation towards other peers in four categories namely SpEed, Correctness, qUality, and Risk-freE (SeCuRE). The value of each category constitutes a fraction of the reliability of individual peer. Another factor that contributes to the reliability of a peer is the peer?s credibility concerning trustworthiness in providing recommendation about other peers. Our trust management scheme is applied in conjunction with our trust model in order to detect malicious and collaborative-based malicious peers. Knowledge of trustworthiness among peers is used in our proposed broadcast model named trustworthy-based estafet multi-point relays (TEMPR). This model is designed to minimise the communication overhead between peers while considering the trustworthiness of the peers such that only trustworthy peer may relay messages to other peers. With our approach, each peer is able to disseminate messages in the most efficient and reliable manner.     

Dimensionality reduction for metabolome data using PCA, PLS, OPLS, and RFDA with differential penalties to latent variables

Dimensionality reduction is an important technique for preprocessing of high-dimensional data. Because only one side of the original data is represented in a low-dimensional subspace, useful information may be lost. In the present study, novel dimensionality reduction methods were developed that are suitable for metabolome data, where observation varies with time. Metabolomics deal with this type of data, which are often obtained in microorganism fermentation processes. However, no dimensionality reduction method that utilizes information from the original data in a positive manner has been reported to date. The ordinary dimensionality reduction methods of principal component analysis (PCA), partial least squares (PLS), orthonormalized PLS (OPLS), and regularized Fisher discriminant analysis (RFDA) were extended by introducing differential penalties to the latent variables in each class. A nonlinear extension of this approach, using kernel methods, was also proposed in the form of kernel-smoothed PCA, PLS, OPLS, and FDA. Since all of these methods are formulated as generalized eigenvalue problems, the solutions can be computed easily. These methods were then applied to intracellular metabolite data of a xylose-fermenting yeast in ethanol fermentation. Visualization in the low-dimensional subspace suggests that smoothed PCA successfully preserves the information about the time course of observations during fermentation, and that RFDA can produce high separation among different strains.     

High-G drop effect on the creep-fatigue failure of SAC solder joints in BGA packages

Microsystem Technologies - The purpose of this work is to show the effects of drop impact on the creep-fatigue evolution of solder balls in an electronic device. Finite element method analysis was...     

A Surface Se-Substituted LiCo[O2−δSeδ] Cathode with Ultrastable High-Voltage Cycling in Pouch Full-Cells

Cycling LiCoO₂ to above 4.5 V for higher capacity is enticing; however, hybrid O anion- and Co cation-redox (HACR) at high voltages facilitates intrinsic O^α− (α < 2) migration, causing oxygen loss, phase collapse, and electrolyte decomposition that severely degrade the battery cyclability. Hereby, commercial LiCoO₂ particles are operando treated with selenium, a well-known anti-aging element to capture oxygen-radicals in the human body, showing an “anti-aging” effect in high-voltage battery cycling and successfully stopping the escape of oxygen from LiCoO₂ even when the cathode is cycled to 4.62 V. Ab initio calculation and soft X-ray absorption spectroscopy analysis suggest that during deep charging, the precoated Se will initially substitute some mobile O^α− at the charged LiCoO₂ surface, transplanting the pumped charges from O^α− and reducing it back to O²⁻ to stabilize the oxygen lattice in prolonged cycling. As a result, the material retains 80% and 77% of its capacity after 450 and 550 cycles under 100 mA g⁻¹ in 4.57 V pouch full-cells matched with a graphite anode and an ultralean electrolyte (2 g Ah⁻¹).     

Design and evaluation of lightweight middleware for personal wireless body area network

This paper presents a lightweight middleware to be used for wireless medical body area networks. The middleware is designed to reside in mobile devices, and acts as a gateway to receive sensor data as well as to control a set of sensor devices attached to the wearer. The main essence of the middleware is to simplify and accelerate the development of wireless healthcare applications by providing highly reusable codes. The architecture of the middleware including its main functions such as data acquisition, dynamic plug-and-play capabilities, on-the-fly sensor reconfiguration, and resource management (i.e., sensor sleep/wake-up, critical self-wake) will be discussed. A security feature as a means to protect critical sensor data from malicious/unauthorized parties has also been incorporated in our proposed middleware. The prototype system of the middleware has been built and is presented in this paper together with its performance measurements.     

Role of growth factors and their receptors in proliferation of microvascular endothelial cells

Investigations over the last decade have established the essential role of growth factors and their receptors during angiogenesis. The biological significance of VEGF, EGF, and bFGF is mediated by their receptors, which belong to the family of tyrosine kinase receptors: Flt-1 (VEGFR-1), KDR (VEGFR-2), EGFR, FGFR-1, FGFR-2, FGFR-3, and FGFR-4. Deeper understanding of the mechanism of activation of these growth factor receptors has allowed the development of a new pharmacological strategy aimed at controlling cancer cell proliferation. The results of a large body of preclinical as well as early clinical studies conducted suggest that targeting the growth factor receptors could represent a significant contribution to cancer therapy.