Angular velocity observer for attitude tracking on SO(3) with the separation property

This paper studies a rigid body attitude tracking control problem with attitude measurements only, when angular velocity measurements are not available. An angular velocity observer is constructed such that the estimated angular velocity is guaranteed to converge to the true angular velocity asymptotically from almost all initial estimates. As it is developed directly on the special orthogonal group, which completely avoids singularities, complexities, or discontinuities caused by minimal attitude representations or quaternions. Then, the presented observer is integrated with a proportional-derivative attitude tracking controller to show a separation type property, where exponential stability is guaranteed for the combined observer and attitude control system.     

Nonlinear Robust Tracking Control of a Quadrotor UAV on SE(3)

This paper provides nonlinear tracking control systems for a quadrotor unmanned aerial vehicle (UAV) that are robust to bounded uncertainties. A mathematical model of a quadrotor UAV is defined on the special Euclidean group, and nonlinear output‐tracking controllers are developed to follow (i) an attitude command, and (ii) a position command for the vehicle center of mass. The controlled system has the desirable properties that the tracking errors are uniformly ultimately bounded, and the size of the ultimate bound can be reduced arbitrarily by control system parameters. Numerical examples illustrating complex maneuvers are provided.     

Using Numerical Analysis to Develop and Evaluate the Method of High Temperature Sous‐Vide to Soften Carrot Texture in Different‐Sized Packages

The high‐temperature sous‐vide (HTSV) method was developed to prepare carrots with a soft texture at the appropriate degree of pasteurization. The effect of heating conditions, such as temperature and time, was investigated on various package sizes. Heating temperatures of 70, 80, and 90 °C and heating times of 10 and 20 min were used to evaluate the HTSV method. A 3‐dimensional conduction model and numerical simulations were used to estimate the temperature distribution and the rate of heat transfer to samples with various geometries. Four different‐sized packages were prepared by stacking carrot sticks of identical size (9.6 × 9.6 × 90 mm) in a row. The sizes of the packages used were as follows: (1) 9.6 × 86.4 × 90, (2) 19.2 × 163.2 × 90, (3) 28.8 × 86.4 × 90, and (4) 38.4 × 86.4 × 90 mm. Although only a moderate change in color (L*, a*, and b*) was observed following HTSV cooking, there was a significant decrease in carrot hardness. The geometry of the package and the heating conditions significantly influenced the degree of pasteurization and the final texture of the carrots. Numerical simulations successfully described the effect of geometry on samples at different heating conditions.     

Comparison of multi-inlet and serpentine channel design on water production of PEMFCs

Two flow field designs, a new multi-inlet design and a conventional serpentine design, for a PEMFC together with relative humidity (RH) and porosity of the gas diffusion layer (GDL) are studied in relation to net water production using a 3-dimensional computational fluid dynamics simulation. The results show that (1) with increasing GDL porosity, discharged water in the serpentine design slightly increases, because accumulated water decreases, whereas discharged water in the multi-inlet design decreases due to a reduction of generated water; (2) although fuel cell power performance improves as RH increases, net water production decreases in both designs, because more water is accumulated; and (3) comparatively higher power and net water production are observed with the multi-inlet design, owing to uniform distributions of reactant gas and water. It is determined that, for net water production without compromising power production, input water should be decreased and, for higher cell performance, flow field design like multi-inlet design should be developed.     

A viscoplastic constitutive model for hot mix asphalt in compression at high confining pressure

In this study, the experimentally observed rate-dependent viscoplastic hardening–softening of hot mix asphalt (HMA) is modeled using Perzyna’s flow rule and a rate-dependent yield stress function. The yield stress function, which is adopted from the convolution integral in linear viscoelasticity, is applied with a strain hardening rule in order to address both the sudden and gradual changes in rate dependence of the viscoplastic media that are due to repetitive creep and recovery loading. The experimental study is performed to characterize the behavior of HMA and verify the developed model at 55 °C with 500 kPa confining pressure. The developed model shows good agreement with the measured viscoplastic responses of HMA under various load levels and pulse times of repetitive creep and recovery loading histories.     

Investigation of flame characteristics using various design parameters in a pulverized coal burner for oxy‐fuel retrofitting

In oxy‐coal combustion for carbon capture and storage, oxygen and recirculated CO₂ are used as oxidizers instead of air to produce CO₂‐rich flue gas. Owing to differences between the physical and chemical properties of CO₂ and N₂, the development of a burner and boiler system based on fundamental understanding of the flame type, heat transfer, and NOx emission is required. In this study, computational fluid dynamic analysis incorporating comprehensive coal conversion models was performed to investigate the combustion characteristics of a 30 MWth tangential vane swirl pulverized coal burner. Various burner design parameters were evaluated, including the influence of the burner geometry on the swirl strength, direct O₂ injection, and O₂ concentrations in the primary and secondary oxidizers. The flame characteristics were sensitive to the oxygen concentration in the primary oxidizer. The performance of direct O₂ injection around the primary oxidizer with low O₂ concentration was dependent on the mixing of the fuel and oxidizer. The predictions showed that swirl number adjustment and careful direct oxygen injection design are essential for retrofitting air‐firing pulverized coal burners as oxy‐firing burners.     

beta-adrenergic modulation of maxi-K channels in vascular smooth muscle via Gi through a membrane-delimited pathway

Direct modulation of large-conductance Ca2+-activated K+ (maxi-K) channel by receptor-associated G protein in rabbit mesenteric arterial smooth muscle cells was studied using the outside-out patch clamp technique. Applying a beta-adrenoceptor agonist (isoproterenol) increased maxi-K channel activity by 75%, and the effect was almost completely abolished by pretreating the cells with pertussis toxin but not with cholera toxin. When the antibody against Gi protein was present in the pipette solution the stimulatory effect of isoproterenol disappeared. These results suggest that beta-adrenoceptor stimulation increases maxi-K channel activity via a membrane-delimited pathway, probably through pertussis toxin-sensitive G protein (Gi).     

Synthesis of a self-equalized dual-passband filter

This letter describes synthesis method for a self-equalized dual-passband filter. Compared to a conventional dual-passband filter, the self-equalized dual-passband filter can reduce bit-error rate (BER) in digital data communications and does not need an external equalizer for group delay equalization. To validate the synthesis method described in this letter, a 10-pole dual-passband filter which has two self-equalized five-pole elliptic-response passbands is synthesized.     

Content Protective Multi‐Agent Platform for MsMu Service and Pattern‐Based Content Management

Recent research on mobile Internet protocol television and digital right management (DRM) interconnections has focused on multimedia technologies designed to enhance content scalability and adaptive content distribution. However, due to the architectural and scalable limitations, recent systems are not flexible and securable with respect to their adaptive content distribution and protective policy management. Therefore, we propose a content protective multi‐agent platform that provides secure multimedia services, correlation management, pattern‐based management, and multisource multi‐use (MsMu)‐based services. Our architecture, supported by DRM, lets us create a rich set of MsMu‐based content protection and seamless multimedia services through the extension of one source multi‐use (OsMu)‐based content services. We have verified our platform, which provides scalable and securable services with a 17% lower service response time by using a testbed.     

Thermal sensation and comfort models for non-uniform and transient environments, part III: Whole-body sensation and comfort

A three-part series presents the development of models for predicting the local thermal sensation (Part I) and local thermal comfort (Part II) of different parts of the human body, and also the whole-body sensation and comfort (Part III) that result from combinations of local sensation and comfort. The models apply to sedentary activities in a range of environments: uniform and non-uniform, stable and transient. They are based on diverse findings from the literature and from body-part-specific human subject tests in a climate chamber. They were validated against a test of automobile passengers. The series is intended to present the models’ rationale, structure, and coefficients, so that others can test them and develop them further as additional empirical data becomes available.A) The whole-body (overall) sensation model has two forms, depending on whether all of the body's segments have sensations effectively in the same direction (e.g warm or cool), or whether some segments have sensations opposite to those of the rest of the body. For each, individual body parts have different weights for warm versus cool sensations, and strong local sensations dominate the overall sensation. If all sensations are near neutral, the overall sensation is close to the average of all body sensations.B) The overall comfort model also has two forms. Under stable conditions, people evaluate their overall comfort by a complaint-driven process, meaning that when two body parts are strongly uncomfortable, no matter how comfortable the other body parts might be, the overall comfort will be near the discomfort level of the two most uncomfortable parts. When the environmental conditions are transient, or people have control over their environments, overall comfort is better than that of the two most uncomfortable body parts. This can be accounted for by adding the most comfortable vote to the two most uncomfortable ones.