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In this study, the hardened properties and spraying characteristics of ultra high strength fiber-reinforced mortar mixed with copper fibers along with nylon fibers and polypropylene fibers are examined. The chemical fibers are added in the expectation that they will prevent cracking during initial curing. It is confirmed that, even with the addition of chemical fibers, the fresh properties of the mortar are similar to those of formulations containing only copper fibers. It is also found spray-application of this formulation achieves sufficient application thickness and that on-site application would be possible.

This paper considers a stochastic systems modelling and stabilization of the rigid body motion of a spacecraft with stochastic disturbances. To rigorously deal with dynamics disturbed by a stochastic process, the rigid body motion is described by a stochastic differential equation on S E (3). This enables us to quantitatively evaluate the uncertainty using stochastic calculus. We present a stochastic stabilizing controller and a stability theorem, which claim that the error of the rigid body motion with respect to a given desired motion is exponentially ultimately bounded in the mean square sense. The resultant stochastic model has no equilibrium point due to persistent noise effect. This makes stability analysis more difficult than the conventional stochastic stability concepts. However, the present stability theorem guarantees that the error exponentially converges to the vicinity of the target state and then remains bounded even under persistent noise. Finally, numerical simulations validate the proposed method. [ABSTRACT FROM AUTHOR]

This paper considers the position and attitude control of a quadcopter in the presence of stochastic disturbances. Basic quadcopter dynamics is modeled as a nonlinear stochastic system described by a stochastic differential equation. Subsequently, the position and attitude control is formulated as a nonlinear stochastic optimal control problem with input saturation constraints. To solve this problem, a continuous-time stochastic differential dynamic programming (DDP) method with input saturation constraints is newly proposed. Finally, numerical simulations demonstrate the effectiveness of the proposed method by comparing it with the linear quadratic Gaussian and the deterministic DDP with input saturation constraints. [ABSTRACT FROM AUTHOR]

Abstract: The relative state transition of spacecraft formation flying is considered in this paper. In eccentric orbits, the Tschauner–Hempel (TH) equations are used to express the relative motion between a deputy spacecraft and a chief spacecraft. Perturbation forces are not considered in the TH equations, and the relative distance between two spacecraft is limited to a short range. In this paper, the effects of the J 2 perturbation forces are considered, and the case of relatively long distance between two spacecraft is focused. A state transition matrix applicable to such cases is derived. The state transition matrix is expressed by adding some compensating terms to the state transition matrix of the TH equations. The usefulness of the proposed state transition matrix relative to the state transition matrix of the TH equations is shown through numerical simulations from the viewpoint of position error. [Copyright &y& Elsevier]

A state transition matrix for formation flying in eccentric orbits is considered in this paper. The relative motion of the formation flying obeys the Tschauner-Hempel equations, which are extended for the presence of a J2 perturbation. Furthermore, the state transition matrix of the Tschauner-Hempel equations is extended for J2, and it is demonstrated that the extended state transition matrix becomes the solution of the extended Tschauner-Hempel equations. Because the extended state transition matrix only uses osculating orbital elements in the initial state and does not use mean orbital elements, an analytical treatment of the state transition matrix is possible. When the state transition matrix uses only the first-order term of J2, the errors sometimes become large compared with the relative distance multiplied byJ2 in a time range that is longer than one orbit period. A method to suppress errors numerically is also proposed. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the effect of J2 perturbations on relative spacecraft position in Earth's near-circular orbits. For the study, researchers utilized solutions to the Hill-Clohessy-Wiltshire (NCW) equations in order to focus on two formations in which the relative distance between the chief and deputy remains constant. They observed that the distance variation for the deputy with respect to the chief was mainly reduced by creating the aforementioned values.

It is well known that convulsions may occur in clinical course of Kawasaki disease. However, the features of such seizures remain unclear. Recent reports have hypothesized that proinflammatory cytokines may contribute to the genesis of febrile convulsions (FC). In the acute phase of Kawasaki disease, proinflammatory cytokines are elevated in serum and CSF. If cytokines play a role in seizure phenomena in patients with Kawasaki disease, FC and seizures in Kawasaki disease might share some clinical features. To clarify the clinical features of convulsion in Kawasaki disease, we investigated 7 patients with Kawasaki disease with convulsions who were diagnosed and treated from November 2003 to November 2005. We found several features of the seizures, as well as the onset age, were diffrent among these clinical entities. The onset of Kawasaki disease was characteristically before six months of age in all patients. Seizure clustering was seen in 5 patients and partial seizures in 4. Prolonged unconsciousness after seizures was seen in one patient, syndrome of inappropriate secretion of ADH (SIADH) in one other. One patient had markedly elevated IL-6 in CSF. These observations led us to speculate that the convulsion of Kawasaki disease may be attributable to an encephalitis. The results of this study suggest that seizure pathophysiology differs between FC and Kawasaki disease.

Phase contrast images were obtained experimentally by using a customized mammography unit with a nominal focal spot size of 100 microm and variable source-to-image distances of up to 1.5 m. The purpose of this study was to examine the applicability and potential usefulness of phase contrast imaging for mammography. A mammography phantom (ACR156 RMI phantom) was imaged, and its visibility was examined. The optical density of the phantom images was adjusted to approximately 1.3 for both the contact and phase contrast images. Forty-one observers (18 medical doctors and 23 radiological technologists) participated in visual evaluation of the images. Results showed that, in comparison with the images of contact mammography, the phantom images of phase contrast imaging demonstrated statistically significantly superior visibility for fibers, clustered micro-calcifications, and masses. Therefore, phase contrast imaging obtained by using the customized mammography unit would be useful for improving diagnostic accuracy in mammography.