Internal oxidation in gold alloys containing small amounts of Fe and Sn

Internal oxidation was observed in gold-rich alloys as substrates for porcelain veneers in dental restorations, which contain small amounts of Fe and Sn. The internal oxidation proceeded with oxygen ions diffusing to the inner part of the alloy through Fe₂O₃ formed at the grain boundaries of the alloy matrix. SnO₂ was formed internally together with the Fe₂O₃. The external oxidation zone was composed of only Fe₂O₃ in a wide range of Fe and Sn concentrations. Fe₃O₄ was formed with Fe₂O₃ in the Sn-rich composition range by reduction of Fe₂O₃ in the presence of Sn. A band mainly composed of SnO₂ was formed at the inside of the internal oxidation zone in the composition range where Fe₃O₄ formed. In the Sn-rich alloys this internal oxidation band of SnO₂ moved to the external oxidation zone.     

Model predictive control with adaptive disturbance prediction and its application to fatty acid distillation column control

This paper describes the results of a joint university-industry study to control a fatty acid distillation sequence, which is plagued with severe disturbance problems. In order to solve the disturbance problem, a model predictive control algorithm is modified in terms of disturbance prediction. Assuming that the dynamics of the unmeasured disturbances is generated by an auto-regressive form, the dynamics of the disturbance can be adaptively identified by using time series data of prediction errors and inputs. Using an identified disturbance model with a process model, future outputs are predicted. Control actions are determined so that the predicted output is as close to the target value as possible. This modified model predictive control aglorithm is applied to a ratio control scheme for three distillation columns. The control system developed has been in use sucessfully for more than six years to produce commercial products.     

Enhanced path smoothing based on conjugate gradient descent for firefighting robots in petrochemical complexes*

The firefighting robot system (FFRS) comprises several autonomous robots that can be deployed to fire disasters in petrochemical complexes. For autonomous navigation, the path planner should consider the robot constraints and characteristics. Specifically, three requirements should be satisfied for a path to be suitable for the FFRS. First, the path must satisfy the maximum curvature constraint. Second, it must be smooth for robots to easily execute the trajectory. Third, it must allow reaching the target location in a specific heading. We propose a path planner that provides smooth paths, satisfy the maximum curvature constraint, and allows a suitable robot heading. The path smoother is based on the conjugate gradient descent, and three approaches are proposed for this path planner to meet all the FFRS requirements. The effectiveness of these approaches is qualitatively and quantitatively evaluated by examining the generated paths. Finally, the path planner is applied to an actual robot to verify the suitability of the generated paths for the FFRS, and planning is applied to another type of robot to demonstrate the wide applicability of the proposed planner.     

An image recognition system aimed at search activities using cyber search and rescue dogs

Disaster response presents major challenges for robotics and computer vision alike. The Cyber‐Enhanced Canine Suit is a suit equipped with a camera, Global Navigation Satellite System (GNSS), and various other sensors, to be worn by search and rescue (SAR) dogs for the purpose of enhancing SAR dog operations. This paper presents an image recognition system for use in disaster scenarios and its integration with the Cyber‐Enhanced Canine Suit platform. The system’s intended use is to spot personal items of missing individuals or other visual clues in video streams from various disaster response platforms. The system facilitates quick learning of targets from limited data and makes providing that data quick and easy. It also provides backtrack recognition functionality, to rapidly find novel targets in the seen footage. We evaluated the recognition system on footage gathered in the field, obtaining promising results. Integrated with the Cyber‐Enhanced Canine Suit, the system can automatically plot detections of search targets onto a map display, to provide operators with a quick overview of what was seen where.     

Highly specific detection of H2O2-dependent luminol chemiluminescence in stimulated human leukocytes using polyvinyl films.

When human polymorphonuclear leukocytes (PMN) were attached to glass coverslips, cells always spread and formed reactive oxygen species prior to any experimental stimulation. To avoid this, a polyvinylidine chloride film was used as an inactive substance to place the cells. Cells engaged in phagocytosis on the film exhibited a specific H2O2-mediated luminol chemiluminescence (LCL) at the cell-particle interface; the cells stimulated with 12-O-tetradecanoylphorbol-13-acetate became aggregated and the LCL was observed at the cell-cell contact. These results corresponded well with those obtained by an electron microscopic H2O2-demonstration method.     

Monotonicity in Optimal Policy of a Flexible Manufacturing Cell Feeding Several Production Lines

This paper deals with an optimal part selection problem tominimize the expected cost, in an automated manufacturing system in which a flexible manufacturing cell produces different parts for several production lines. The optimal control problem is formulated as an undiscounted semi-Markov decision process. Properties of the optimal policy are analyzed. Moreover, sufficiency conditions are derived for the optimal policy to be of control iimit type.     

A comparative study of the use of the generalized hold function for HDDs

This work is concerned with the application of H/sub /spl infin// control with the generalized hold function (GHF) to track-following control of hard disk drives (HDDs). In HDDs, the sampling frequency is limited primarily by the fact that a high sampling frequency tends to decrease the available data storage capacity of the devices, since the position error signal (PES) must be stored on the disk. Under such conditions, GHF provides a possible way to enhance servo performance without requiring more PES data. We investigate its possibility, comparing the results with other conventional H/sub /spl infin// control design results, including continuous/discrete-time and single/multirate control. Our results show that this controller has better performance due to the nature of the control input of the GHF.     

Control of the coating layer thickness of TiO2–SiO2 core–shell hybrid particles by liquid phase deposition

This paper describes control of the coating layer thickness and the crystallite size of the core–shell hybrid particles by controlling the process parameter. The core–shell hybrid particles were prepared using liquid phase deposition (LPD). We confirmed that the homogeneous coating was attained from the result of the zeta potential and the transmission electron microscope (TEM) observation. Furthermore, the coating layer microstructure was estimated using Brunauer–Emmett–Teller (BET) method. The obtained coating layer of titania was estimated using the band gap energy. Results indicate that the blue shift of the band gap energy signifies that the physical property of the hybrid particles was controlled by the coating layer thickness and the crystallite size, which are determined by the processing parameters.