Oxygen transport,thermal and electrochemical properties of NdBa0.5Sr0.5Co2O5+δ cathode for SOFCs

In this study, the crystal structure, thermal, oxygen transport, electrical conductivity and electrochemical properties of the perovskite NdBa_0.5Sr_0.5Co₂O_5+δ (NBSC55) are investigated. In the temperature range of 250 °C–350 °C, the weight loss upon heating was due to a partial loss of lattice oxygen and along with a reduction of Co⁴⁺ to Co³⁺. The tend of weight-loss slows down as temperature increased above 350 °C indicating a reduction of Co³⁺ to Co²⁺ during this stage. The oxygen migration is dominated by surface exchange process at high temperature range (650-800 °C); however, the bulk diffusion process prevails at low temperature range (500–600 °C). For long-term testing, the polarization resistance of NBSC55 increases gradually form 3.13 Ω cm² for 2 h to 3.34 Ω cm² for 96 h at 600 °C and an increasing-rate for polarization resistance is around 0.22% h^?1. The power density of the single cell with NBSC55 cathode reached 341 mW cm^?2 at 800 °C.     

Use of Zebrafish Embryo Assay to Evaluate Toxicity and Safety of Bioreactor-Grown Exopolysaccharides and Endopolysaccharides from European Ganoderma applanatum Mycelium for Future Aquaculture Applications

Natural mycelial exopolysaccharide (EPS) and endopolysaccharide (ENS) extracted from bioreactor-cultivated European Ganoderma applanatum mushrooms are of potential high commercial value for both food and adjacent biopharmaceutical industries. In order to evaluate their potential toxicity for aquaculture application, both EPS (0.01–10 mg/mL) and ENS (0.01–10 mg/mL) extracts were tested for Zebrafish Embryo Toxicity (ZFET); early development effects on Zebrafish Embryos (ZE) were also analyzed between 24 and 120 h post-fertilization (HPF). Both EPS and ENS are considered non-toxic with LC₅₀ of 1.41 mg/mL and 0.87 mg/mL respectively. Both EPS and ENS did not delay hatching and teratogenic defect towards ZE with <1.0 mg/mL, respectively. No significant changes in the ZE heart rate were detected following treatment with the two compounds tested (EPS: 0.01–10 mg/mL: 176.44 ± 0.77 beats/min and ENS: 0.01–10 mg/mL: 148.44 ± 17.75 beats/min) compared to normal ZE (120–180 beats/min). These initial findings support future pre-clinical trials in adult fish models with view to safely using EPS and ENS as potential feed supplements for supplements for development of the aquaculture industry.     

A note on models for non-probabilistic analysis of packet switching networks

We consider two models commonly used in the literature to model adversarial injection of packets into a packet switching network. We establish the relation between these two types of models, and between them and the set of sequences of packets that allow stability. We also consider the adaptive setting in which packets are injected with only their source and destination but without a prescribed path to follow.     

Bounded Error Schemes for the Wave Equation on Complex Domains

This paper considers the application of the method of boundary penalty terms (SAT) to the numerical solution of the wave equation on complex shapes with Dirichlet boundary conditions. A theory is developed, in a semi-discrete setting, that allows the use of a Cartesian grid on complex geometries, yet maintains the order of accuracy with only a linear temporal error-bound. A numerical example, involving the solution of Maxwell’s equations inside a 2-D circular wave-guide demonstrates the efficacy of this method in comparison to others (e.g., the staggered Yee scheme)—we achieve a decrease of two orders of magnitude in the level of the L₂-error.     

Novel hybrid DNN approaches for speaker verification in emotional and stressful talking environments

Neural Computing and Applications - In this work, we conducted an empirical comparative study of the performance of text-independent speaker verification in emotional and stressful environments....     

Robust Fault Diagnosis for Quadrotor UAVs Using Adaptive Thau Observer

A robust Fault Diagnosis (FD) scheme for a real quadrotor Unmanned Aerial Vehicle (UAV) is proposed in this paper. Firstly, a novel Adaptive Thau observer (ATO) is developed to estimate the quadrotor system states and build a set of offset residuals to indicate actuators’ faults. Based on these residuals, some rules of Fault Diagnosis (FD) are designed to detect and isolate the faults as well as estimate the fault offset parameters. Secondly, a synthetic robust optimization scheme is presented to improve Fault Estimation (FE) accuracies, three key issues include modeling uncertainties, and magnitude order unbalances as well as noises are addressed. Finally, a typical fault of rotors is simulated and injected into one of four rotors of the quadrotor, and experiments for the FD scheme have been carried out. Unlike former research works on the FD schemes for quadrotors, our proposed FD scheme based on the ATO can not only detect and isolate the failed actuators, but also estimate the fault severities. Regardless of roughness of the real flying data, the FD results still have sufficient FE accuracies.     

Simple Robust PID Tuning for Magnetic Levitation Systems Using Model-free Control and $${{\cal H}_\infty}$$ ℋ ∞ Control Strategies

International Journal of Control, Automation and Systems - This paper proposes two control techniques to provide robust tracking for magnetic levitation systems (MLS): model-free control (MFC) and...     

Color accurate monitors: Basic features and comparison of four monitors

Color accurate monitors are high resolution, luminance‐controlled displays with very large color gamut. They have internal controls to match specific color standards (e.g., sRGB, Adobe‐RGB, REC‐709) and well‐defined gamma functions (mostly γ = 2.2, but others such as Equal Probability of Detection, Digital Imaging and Communications in Medicine). Usually, they come with external tools for automatic calibration (like Chroma 5 or Spider) and for communicating with the host computer through USB port, and with software to control the calibration process. Most of them allow a calibration to a specific customer selected color gamut, besides the precalibrated standards, but limit the gray levels calibration to a gamma type function (typically γ = 2.2). Their unique properties, challenges, and applications will be discussed. A comparison between the properties of four monitors and optical test results of their parameters is presented.     

Superior Thermoelectric Performance of Textured Ca3Co4−xO9+δ Ceramic Nanoribbons

Calcium cobaltite Ca₃Co_4−xO_9+δ (CCO) is a promising p-type thermoelectric (TE) material for high-temperature applications in air. The grains of the material exhibit strong anisotropic properties, making texturing and nanostructuring mostly favored to improve thermoelectric performance. On the one hand multitude of interfaces are needed within the bulk material to create reflecting surfaces that can lower the thermal conductivity. On the other hand, low residual porosity is needed to improve the contact between grains and raise the electrical conductivity. In this study, CCO fibers with 100% flat cross sections in a stacked, compact form are electrospun. Then the grains within the nanoribbons in the plane of the fibers are grown. Finally, the nanoribbons are electrospun into a textured ceramic that features simultaneously a high electrical conductivity of 177 S cm⁻¹ and an immensely enhanced Seebeck coefficient of 200 µV K⁻¹ at 1073 K are assembled. The power factor of 4.68 µW cm⁻¹ K⁻² at 1073 K in air surpasses all previous CCO TE performances of nanofiber ceramics by a factor of two. Given the relatively high power factor combined with low thermal conductivity, a relatively large figure-of-merit of 0.3 at 873 K in the air for the textured nanoribbon ceramic is obtained.     

Guaranteeing the Diversity of Number Generators

A major problem in using iterative number generators of the form x_i=f(x_i−1) is that they can enter unexpectedly short cycles. This is hard to analyze when the generator is designed, hard to detect in real time when the generator is used, and can have devastating cryptanalytic implications. In this paper we define a measure of security, called sequence diversity, which generalizes the notion of cycle-length for noniterative generators. We then introduce the class of counter-assisted generators and show how to turn any iterative generator (even a bad one designed or seeded by an adversary) into a counter-assisted generator with a provably high diversity, without reducing the quality of generators which are already cryptographically strong.